Increasing basic farmland soil productivity has significance in reducing fertilizer application and maintaining high yield of crops. In this study, we defined that the basic soil productivity （BSP） is the production...Increasing basic farmland soil productivity has significance in reducing fertilizer application and maintaining high yield of crops. In this study, we defined that the basic soil productivity （BSP） is the production capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local environment and field management. Based on 22-yr （1990-2011） long-term experimental data on black soil （Typic hapludoll） in Gongzhuling, Jilin Province, Northeast China, the decision support system for an agro-technology transfer （DSSAT）-CERES-Maize model was applied to simulate the yield by BSP of spring maize （Zea mays L.） to examine the effects of long-term fertilization on changes of BSP and explore the mechanisms of BSP increasing. Five treatments were examined： （1） no-fertilization control （control）; （2） chemical nitrogen, phosphorus, and potassium （NPK）; （3） NPK plus farmyard manure （NPKM）; （4） 1.5 time of NPKM （1.5NPKM） and （5） NPK plus straw （NPKS）. Results showed that after 22-yr fertilization, the yield by BSP of spring maize significantly increased 78.0, 101.2, and 69.4% under the NPKM, 1.5NPKM and NPKS, respectively, compared to the initial value （in 1992）, but not significant under NPK （26.9% increase） and the control （8.9% decrease）. The contribution percentage of BSP showed a significant rising trend （P〈0.05） under 1.5NPKM. The average contribution percentage of BSP among fertilizations ranged from 74.4 to 84.7%, and ranked as 1.5NPKM〉NPKM〉NPK〉NPKS, indicating that organic manure combined with chemical fertilizers （I.5NPKM and NPKM） could more effectively increase BSP compared with the inorganic fertilizer application alone （NPK） in the black soil. This study showed that soil organic matter （SOM） was the key factor among various fertility factors that could affect BSP in the black soil, and total N, total P and/or available P also played important role in BSP increasing. Compared with the chemical fertilization, a balanced chemical plus manure or straw fertilization （NPKM or NPKS） not only increased the concentrations of soil nutrient, but also improved the soil physical properties, and structure and diversity of soil microbial population, resulting in an iincrease of BSP. We recommend that a balanced chemical plus manure or straw fertilization （NPKM or NPKS） should be the fertilization practices to enhance spring maize yield and improve BSP in the black soil of Northeast China.展开更多
Soil organic carbon （SOC） and soil Olsen-P are key soil fertility indexes but information on their relationships is limited particularly under long-term fertilization. We investigated the relationships between SOC a...Soil organic carbon （SOC） and soil Olsen-P are key soil fertility indexes but information on their relationships is limited particularly under long-term fertilization. We investigated the relationships between SOC and the percentage of soil Olsen-P to total P （PSOPTP） under six different 15-yr （1990-2004） long-term fertilizations at two cropping systems in northern China. These fertilization treatments were （1） unfertilized control （control）; （2） chemical nitrogen （N）; （3） N plus chemical P （NP）; （4） NP plus chemical potassium （NPK）; （5） NPK plus animal manure （NPKM） and （6） high NPKM （hNPKM）. Compared with their initial values in 1989 at both sites, during the 1 lth to 15th fertilization years annual mean SOC contents were significantly increased by 39.4-47.0% and 58.9-93.9% at Gongzhuling, Jilin Province, and Urumqi, Xinjiang, China, under the two NPKM fertilizations, respectively, while no significant changes under the no-P or chemical P fertilization. During the 1 lth to 15th fertilization years, annual mean PSOPTP was respectively increased by 2.6-4.2 and 5.8-14.1 times over the initial values under the two chemical P fertilizations and the two NPKM fertilizations, but was unchanged in their initial levels under the two no-P fertilizations at both sites. Over the 15-yr long-term fertilization SOC significantly positively correlated with PSOPTP （r^2=0.55-0.79, P〈0.01）. We concluded that the combination of chemical P plus manure is an effective way to promote SOC accumulation and the percentage of soil Olsen-P to total P at the two mono-cropping system sites in northern China.展开更多
The availability of elite germplasm resources with high yield and quality potentials is very important for development of cultivars in wheat. Thus, seeking such resources has been the continuous effort of breeder comm...The availability of elite germplasm resources with high yield and quality potentials is very important for development of cultivars in wheat. Thus, seeking such resources has been the continuous effort of breeder community. In this study, genetic analysis of a novel resource, Triticum spelta line CSCR6, from Australia was made by use of a recombination inbred line （RIL） population of 82 individuals from the cross between CSCR6 and another Australian hexaploid wheat cultivar, Lang. Data of a multiple environmental test was employed to genetically dissect quantitative trait loci （QTL） for agronomic traits such as plant height （PH）, spike length （SL）, spikelet per spike （SPI）, grain number per spike （GNS） and thousand grains weight （TGW） and for quality traits including grain protein content （GPC）, gluten content （GC）, grain hardness （GH）, falling number （FN） and sedimentation value （SV）. A 24 QTLs with additive effects were detected for all the investigated traits, and were located on chromosomes 1B, 1D, 2B, 3A, 3B, 3D, 4B, 5A, 5B, 7A, and 7B, respectively. Some QTLs located on 2B and 4B showed higher explanation of phenotypic variances and were not obviously interacted with environment. A QTL in the marker interval of wPT-5334-wPT-4918 （near the locus barc 0199） on 4B gave the highest contribution ratio of 30.76% on PH, while Qgpc-4B and Qgc-4B gave 13.07 and 14.70% contribution ratio on GPC and GC, respectively. Qph-2B, Qgns-2B, and Qgpc-2B showed 13.36, 10.00, and 10.79% contribution ratio on PH, GNS and GPC, respectively. Also, a QTL on 5A, Qsl- 5A, could explain 25.12% of phenotypic variance on SL. For most of agronomic and quality traits, CSCR6 alleles produced increase effects. The fact that a number of loci affecting the investigated traits were detected in T. spelta line CSCR6 revealed that it could offer a new opportunity for the manipulation of these traits in wheat breeding programs.展开更多
To classify the Chinese wintersweet（Chimonanthus praecox） cultivars and to study their evolution based on pollen morphology.Pollens of 12 representative wintersweet cultivars were examined by scanning electron micro...To classify the Chinese wintersweet（Chimonanthus praecox） cultivars and to study their evolution based on pollen morphology.Pollens of 12 representative wintersweet cultivars were examined by scanning electron microscopy（SEM）.Q-cluster analysis was carried out based on the observation results.Results are as follows：（1） The pollen grains were 2lobed circular in polar view,elliptic in equatorial view.The pollen shapes were spheroidal or super-spheroidal by P/E（polar axis length/equatorial axis length） criteria.（2） According to pollen exine ornamentation,it was indicated that white wintersweet is most original.Yellow floral group could be classified into three subgroups：purple-hearted,halo-hearted and yellow-hearted type.Their evolutionary relationship was purple-hearted halo-hearted yellow-hearted.（3） Different wintersweet cultivars showed a different exine sculpture.Palynological analysis could be used in the classification of wintersweet cultivars.The result of cluster analysis indicated that the cultivars could be classified into three groups with a similarity coefficient of 0.41.Each group had similar pollen exine sculpture.It was found that the palynological classification coincided well with morphological classification.Our results support the suggestion that purple streaks or patches of inner-petals should be served as the first-order criteria in wintersweet classification.展开更多
Uppermost-internode diameter(UID)is a key morphological trait associated with spike development and yield potential in wheat.Our understanding of its genetic basis remains largely unknown.Here,quantitative trait loci(...Uppermost-internode diameter(UID)is a key morphological trait associated with spike development and yield potential in wheat.Our understanding of its genetic basis remains largely unknown.Here,quantitative trait loci(QTLs)for UID with high-density genetic maps were identified in five wheat recombinant inbred line(RIL)populations.In total,25 QTLs for UID were detected in five RIL populations,and they were located on chromosomes 1A,1D(3 QTL),2B(2),2D(3),3B,3D,4A,4B(3),4D,5A(5),5B(2),6B,and 7D.Of them,five major and stable QTLs(QUid.sau-2CN-1D.1,QUid.sau-2SY-1D,QUid.sau-QZ-2D,QUid.sau-SC-3D,and QUid.sau-AS-4 B)were identified from each of the five RIL populations in multiple environments.QUid.sau-2CN-1D.1,QUid.sau-2SY-1D and QUid.sau-SC-3D are novel QTLs.Kompetitive Allele Specific PCR(KASP)markers tightly linked to them were further investigated for developing near-isogenic lines(NILs)carrying the major loci.Furthermore,candidate genes at these intervals harboring major and stable QTLs were predicted,and they were associated with plant development and water transportation in most cases.Comparison of physical locations of the identified QTL on the‘Chinese Spring’reference genome showed that several QTLs including two major ones,QUid.sau-2CN-1D.1 and QUid.sau-2 SY-1 D,are likely allelic confirming their validity and effectiveness.The significant relationships detected between UID and other agronomic traits and a proper UID were discussed.Collectively,our results dissected the underlying genetic basis for UID in wheat and laid a foundation for further fine mapping and map-based cloning of these QTLs.展开更多
Natural regeneration is a critical component of forest ecosystems sustainability. Local extinction can occur without adequate regenerationor seedling recruitment prior to adult senescence. The urban and peri-urban env...Natural regeneration is a critical component of forest ecosystems sustainability. Local extinction can occur without adequate regenerationor seedling recruitment prior to adult senescence. The urban and peri-urban environment is particularly challenging for recruitment. For example, although many forest species have specific requirements involving fire events, few opportunities associated with fire exist in contemporary urban and peri-urban environments. For our study species, Eucalyptus gomphocephala, en masse recruitment can occur in ashbeds following a hot fire. However, this may not occur following low-intensity, fuel reduction burns that are prescribed for many E. gomphocephala woodlands and forests. Nevertheless, ashbeds could be created by constructing and burning coarse woody debris (CWD) piles. In a series of collaborative case studies involving community groups, NGOs and Local and State Government agencies, we investigated whether seedling recruitment could be facilitated through broadcast seeding after: a) creating CWD piles prior to a low intensity, prescribed burn;b) naturally-occurring ashbeds following a hot summer wildfire;and c) creating CWD piles and then burning the piles only. We found that regeneration of this post-fire, canopy gap regenerator can be facilitated by broadcast seeding naturally occurring or created ashbeds. However, it seems that protection from seed harvesters and herbivores is vital. These case studies provide tools that can be used to preserve the natural demographics in populations with specific regeneration requirements in a range of environments by leveraging natural recruitment processes and community involvement. Importantly, it is the conservation of these urban and peri-urban ecosystems that will be vital in maintaining connection between people and the environment into the future.展开更多
A pot experiment was conducted to examine the activity of antioxidant enzymes, the content of malondialdehyde （MDA）, proline and protein, and Cd uptake in different rice cultivars exposed to Cd （0, 1 and 5 mg/kg） ...A pot experiment was conducted to examine the activity of antioxidant enzymes, the content of malondialdehyde （MDA）, proline and protein, and Cd uptake in different rice cultivars exposed to Cd （0, 1 and 5 mg/kg） in the presence of organic acids and ethylenediamine tetraacetic acid （EDTA）. The results showed the increase in activity of dismutase （SOD）, contents of proline and protein but a decline in activities of peroxidase （POD） and catalase （CAT）, and MDA content for cultivars Xiushui63 and IIyou527. The resistance to Cd was higher in Xiushui63 than that in IIyou527 under the same Cd treatment. Cadmium contents in grain, straw and roots of both cultivars were markedly reduced in the presence of organic acids and EDTA. Grain Cd contents was the highest for plants treated with organic acids, followed by organic acids ＋ 1/2EDTA, and the lowest with EDTA; Cd contents in straw and root were the lowest for plants treated with organic acids, followed by organic acids ＋ 1/2EDTA, and the highest with EDTA treatment when exposed to Cd.展开更多
Improving nitrogen use efficiency （NUE） and decreasing N loss are critical to sustainable agriculture. The objective of this research was to investigate the effect of various fertilization regimes on yield, NUE, N a...Improving nitrogen use efficiency （NUE） and decreasing N loss are critical to sustainable agriculture. The objective of this research was to investigate the effect of various fertilization regimes on yield, NUE, N agronomic efficiency （NAE） and N loss in long-term （16- or 24-yr） experiments carried out at three rice-wheat rotation sites （Chongqing, Suining and Wuchang） in subtropical China. Three treatments were examined： sole chemical N, N＋phosphorus （NP）, and NP＋potassium （NPK） fertilizations. Grain yields at three sites were significantly increased by 9.3-81.6% （rice） and 54.5-93.8% （wheat） under NP compared with N alone, 1.7-9.8% （rice） and 0-17.6% （wheat） with NPK compared with NP. Compared to NP, NUE significantly increased for wheat at Chongqing （9.3%） and Wuchang （11.8%）, but not at Suining, China. No changes in NUE were observed in rice between NP and NPK at all three sites. The rice-wheat rotation＇s NAE was 3.3 kg kg1 higher under NPK than under NP at Chongqing, while NAE was similar for NP and NPK at Suining and Wuchang. We estimated that an uptake increase of 1.0 kg N hal would increase 40 kg rice and 30 kg wheat ha-1. Nitrogen loss/input ratios were -60, -40 or -30% under N, NP or NPK at three sites, indicating significant decrease of N loss by P or PK additions. We attribute part of the increase in NUE soil N accumulation which significantly increased by 25-55 kg ha-1 yr1 under NPK at three sites, whereas by 35 kg ha-1 yr-1 under NP at Chongqing only. This paper illustrates that apply P and K to wheat, and reduce K application to rice is an effective nutrient management strategy for both the NUE improvement and N losses reduction in China.展开更多
Aims Mycorrhizas(fungal roots)play vital roles in plant nutrient acquisition,performance and productivity in terrestrial ecosystems.Arbuscular mycorrhizas(AM)and ectomycorrhizas(EM)are mostly important since soil nutr...Aims Mycorrhizas(fungal roots)play vital roles in plant nutrient acquisition,performance and productivity in terrestrial ecosystems.Arbuscular mycorrhizas(AM)and ectomycorrhizas(EM)are mostly important since soil nutrients,including NH+4,NO3 and phosphorus,are translocated from mycorrhizal fungi to plants.Individual species,genera and even families of plants could be interconnected by mycorrhizal mycelia to form common mycorrhizal networks(CMNs).The function of CMNs is to provide pathways for movement or transfer of nutrients from one plant to another.In the past four decades,both ^(15)N external labeling or enrichment(usually expressed as atom%)and ^(15)N naturally occurring abundance(d^(15)N,&)techniques have been employed to trace the direction and magnitude of N transfer between plants,with their own advantages and limitations.Important Findings The heavier stable isotope ^(15)N is discriminated against 14N during biochemical,biogeochemical and physiological processes,due to a greater atomic mass.In general,non-N2-fixing plants had greater d^(15)N values than N2-fixing(;0&)ones.Foliar d^(15)N often varied by 5 to 10&in the order:non-mycorrhizas/AMs>EMs>ericoid mycorrhizas.Differences in d^(15)N(&)or ^(15)N(atom%)values could thus provide N transfer information between plants.A range of between 0 to 80%of one-way N transfer had been observed from N2-fixing mycorrhizal to non-N2-fixing mycorrhizal plants,but generally less than or around 10%in the reverse direction.Plant-to-plant N transfer may provide practical implications for plant performance in N-limited habitats.Considering that N translocation or cycling is crucial,and the potential benefits of N transfer are great in both agricultural and natural ecosystems,more research is warranted on either oneway or two-way N transfers mediated by CMNs with different species and under field conditions.展开更多
Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems. We analyzed the historical （1990-2005） observations on four agric...Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems. We analyzed the historical （1990-2005） observations on four agricultural long-term experiments in China （Changping, Chongqing, Gongzhuling and Qiyang） under four different fertilizations, i.e., no-fertilizer （control）, sole chemical nitrogen fertilizer （FN）, sole chemical phosphorous and potassium fertilizers （FPK） and chemical nitrogen, phosphorous and potassium fertilizers （FNPK）. The significant decline in topsoil pH was caused not only by chemical N fertilization （0.29 and 0.89？pH at Gongzhuling and Qiyang, respectively） but also by chemical PK fertilization （0.59？pH at Gongzhuling）. The enhancement of available nutrients in the topsoil due to long-term direct nutrients supply with chemical fertilizers was in the descending order of available P （168-599%）〉available K （16-189%）〉available N （9-33%）. The relative rate of soil pH decline was lower under long-term judicious chemical fertilization （-0.036-0.034 ？pH yr-1） than that under long-term sole N or PK fertilization （0.016-0.086 ？pH yr-1）. Long-term judicious chemical fertilization with N, P and K elements decreases the nutritional limitation to normal crop growth, under which more N output was distributed in biomass removal rather than the loss via nitrate leaching. We concluded that the N distribution percentage of nitrate leaching to biomass removal might be a suitable indicator to the sensitivity of agricultural ecosystems to acid inputs.展开更多
Aims Despite acknowledgement that interactions among native and exotic species are important for determining the structure and diversity of novel communities,directed experiments using mul-tiple exotics from the same ...Aims Despite acknowledgement that interactions among native and exotic species are important for determining the structure and diversity of novel communities,directed experiments using mul-tiple exotics from the same system are rare.Recent observational studies have highlighted distinct ways that exotic species interface with resident natives across invaded communities.The correlative nature of these studies,however,has provided few details about the mechanisms driving distinct interaction outcomes within the same communities.Our aim was to determine how three exotic annual plant species with distinct relationships with local plant diversity impact the performance of a co-occurring native annual in the York gum-jam woodlands of Western Australia.Methods We grew species in experimental communities in growth chambers at varying total planting densities to assess how interaction out-comes varied among natives and exotics across a gradient of com-petition intensity.We measured a variety of performance responses,including survival,biomass and population-level and individual-level reproductive investment.Important Findings Overall,the effects of interspecific versus intraspecific competi-tion on performance varied with the identity and density of exotic competitors.The exploitative exotic grass Bromus madritensis was dominant in polyculture,whereas the diminutive grass Pentameris airoides conferred weak intraspecific competition and interspe-cific facilitation on native Waitzia nitida.The exotic broadleaf forb,Hypochaeris glabra,suppressed growth and survival of W.nitida,while W.nitida had weakly negative,neutral or positive effects on all exotics.These outcomes highlight the complexity of interac-tions impacting the diversity,stability and structure of novel plant communities.As few of these communities contain a single exotic species,understanding the competitive dynamics occurring in diverse novel communities is critical for their conservation and restoration.展开更多
The significance of mycorrhizas(fungal roots in 90% of land plants) in plant nutrient acquisition and growth,element biogeo-chemical cycling and maintaining of terrestrial ecosystem structures has been globally establ...The significance of mycorrhizas(fungal roots in 90% of land plants) in plant nutrient acquisition and growth,element biogeo-chemical cycling and maintaining of terrestrial ecosystem structures has been globally established for more than 120 years.Great progress in mycorrhizal research in the past 60 years(1950-2009,1981-2009 in particular) has also been made across China,particularly in the mainland,Hong Kong and Taiwan.For instance,a total of 20 new and ~120 records of arbuscular mycorrhizal(AM) fungal species,30 new and ~800 records of ectomycorrhizal(EM) fungal species,a dozen of new and ~100 records of orchid mycorrhizal(OM) fungal species have been isolated by morphological observation and/or molecular identification in China since the 1950s.Great accomplishment has also been made in the following area,including fungal species richness and genetic structure,relationships between species composition and plant taxa,effects of mycorrhizal fungi on plant nutrient uptake and growth,resistances to pathogens and interactions with other soil microorganisms,potential of mycorrhizal fungi in phytoremediation and/or land reclamation,alterations of enzymatic activities in mycorrhizal plants,and elevated CO2 and O3 on root colonization and species diversity.Unfortunately,the international community cannot easily appreciate almost all Chinese mycorrhizal studies since the vast majority of them have been published in Chinese and/or in China-based journals.The aim of this review is to make a comprehensive exposure of the past and present China's major mycorrhizal research to the whole world,and then to suggest potential directions for the enhancement of future mycorrhizal research within and/or between the Chinese and international mycorrhizal community.展开更多
Arbuscular mycorrhizal(AM) fungi form mutualistic symbioses with most plant species and play important roles in ecosystems.Knowledge of the response of AM fungi to temperature change will improve our understanding of ...Arbuscular mycorrhizal(AM) fungi form mutualistic symbioses with most plant species and play important roles in ecosystems.Knowledge of the response of AM fungi to temperature change will improve our understanding of the function of AM fungal community under global climate change scenarios in ecosystems.The effects of constant warming on AM fungal communities have been investigated previously,but responses to asymmetrical warming over 24-h periods have never been documented in natural ecosystems.In this study,we examined AM fungal communities in a full factorial design including day-time and night-time warming in a semiarid steppe in northern China.Day-time and 24-h warming,but not night-time warming,significantly increased AM fungal spore density.In contrast,none of the three warming regimes had a significant effect on AM fungal extra radical hyphal density.Atotal of 161 operational taxonomic units(OTUs) of AM fungi were recovered by 454 pyrosequencing of 18 S r DNA.Day-time,night-time,and 24-h warming all significantly increased AM fungal OTU richness.Some AM fungal OTUs showed a significant bias toward day-time,night-time or24-h warming.The AM fungal community composition was significantly affected by night-time warming,but not by day-time and 24-h warming.Our finding highlighted different responses of AM fungal spore density and community composition to asymmetrical warming.This study might improve our understanding of ecosystem functioning of AM fungal community under global climate change scenarios in a semiarid steppe ecosystem.展开更多
Sustainable potassium （K） management at different soil sites requires understanding the relationships between crop productivity and long-term K fertilizations on a regional or national scale. We analyzed responses o...Sustainable potassium （K） management at different soil sites requires understanding the relationships between crop productivity and long-term K fertilizations on a regional or national scale. We analyzed responses of grain yield of wheat （Triticum aestivurn L.） and maize （Zea mays L.）, K efficiency, and partial balance （difference between K input through fertilizer and K output in the aboveground biomass） during 15- （1990-2005） or 18-year （1990-2008） K fertilizations at five distinctive agroecologicai zones across China. Compared to the inorganic nitrogen （N） and phosphorus （P） fertilization, the inorganic NPK fertilization significantly increased grain yields of wheat （21%） and maize （16% 72%） at Qiyang and Changping, where soils have low exchangeable and non-exchangeable K contents, but not at Uriimqi, Yangling and Zhengzhou, where soils have a high exchangeable and non-exchangeable K and/or low N/K ratio in crop plants. Compared to the inorganic NPK fertilization, the inorganic NPK （30% N） and organic manure （70~~ N） fertilization （NPKM） increased grain yields of wheat （14%-40%） and maize （9%-6170） at four sites, but not at Zhengzhou. For a productivity of wheat at 2-5 t ha-1 or maize at 3-6 t ha 1, 13-26 or 9-17 kg K ha 1 were required to produce 1.0 t wheat or maize. The NP fertilization resulted in the lowest negative partial K balance and accumulated 52 kg K ha-1 year-1 less than the NPK fertilization, which accumulated 28 kg ha 1 year-1 less K than the NPKM fertilization. A re-evaluation of the site-specific fertilization effects on N/K ratio in crop plants and soil K accumulation under current NPK and NPKM t＇ertilization is urgently needed to increase both crop yield and K use efficiency at different agroecologicai zones across China.展开更多
Two new types of signaling compounds have been discovered in wildfire smoke due to their ability to stimulate seed germination. The first discovered were karrikins, which share some structural similarity with the stri...Two new types of signaling compounds have been discovered in wildfire smoke due to their ability to stimulate seed germination. The first discovered were karrikins, which share some structural similarity with the strigol- actone class of plant hormones, and both signal through a common F-box protein. However, karrikins and strigolactones operate through otherwise distinct signaling pathways, each distinguished by a specific a/13 hydrolase protein. Genetic analysis suggests that plants contain endogenous compounds that signal specifically through the karrikin pathway. The other active compounds discovered in smoke are cyanohydrins that release germination-stimulating cyanide upon hydrolysis. Cyanohydrins occur widely in plants and have a role in defense against other organisms, but an additional role in endogenous cyanide signaling should also now be considered.展开更多
Arbuscular mycorrhizal （AM）-mediated plant physiological activities could contribute to plant salt tolerance. However, the biochemical mechanism by which AM fungi enhance salt tolerance of halophytie plants is uncle...Arbuscular mycorrhizal （AM）-mediated plant physiological activities could contribute to plant salt tolerance. However, the biochemical mechanism by which AM fungi enhance salt tolerance of halophytie plants is unclear. A pot experiment was conducted to determine whether salt tolerance of the C3 halophyte Suaeda salsa was enhanced by the AM fungus Glomus rnosseae. When 60-day-old S. salsa seedlings were subjected to 400 mmol L-1 NaC1 stress for 35 days, plant height, number of leaves and branches, shoot and root biomass, and root length of G. mosseae-colonized seedlings were significantly greater than those of the nonmycorrizal seedlings. Leaf superoxide dismutase （SOD） activity at all sampling times （weekly for 35 days after salt stress was initiated） and leaf catalase （CAT） activity at 2 and 3 weeks after salt stress was initiated were also significantly enhanced in G. mosseae-colonized S. salsa seedlings, while the content of leaf malondialdehyde （MDA）, a product of membrane lipid peroxidation, was significantly reduced, indicating an alleviation of oxidative damage. The corresponding leaf isoenzymes of SOD （Fe-SOD, Cu/Zn-SOD1, and Cu/Zn-SOD2） and CAT （CAT1 and CAT2） were also significantly increased in the mycorrhizal seedlings after 14 days of 400 mmol L-1 NaC1 stress. Our results suggested that G. rnosseae increased salt tolerance by increasing SOD and CAT activities and forming SOD and CAT isoforms in S. salsa seedlings.展开更多
Introduction:Novel ecosystems that contain new combinations of invasive alien plants(IAPs)present a challenge for managers.Yet,control strategies that focus on the removal of the invasive species and/or restoring hist...Introduction:Novel ecosystems that contain new combinations of invasive alien plants(IAPs)present a challenge for managers.Yet,control strategies that focus on the removal of the invasive species and/or restoring historical disturbance regimes often do not provide the best outcome for long-term control of IAPs and the promotion of more desirable plant species.Methods:This study seeks to identify the primary drivers of grassland invasion to then inform management practices toward the restoration of native ecosystems.By revisiting both published and unpublished data from experiments and case studies within mainly an Australian context for native grassland management,we show how alternative states models can help to design control strategies to manage undesirable IAPs by manipulating grazing pressure.Results:Ungulate grazing is generally considered antithetical to invasive species management because in many countries where livestock production is a relatively new disturbance to grasslands(such as in Australia and New Zealand as well as Canada and the USA),selective grazing pressure may have facilitated opportunities for IAPs to establish.We find that grazing stock can be used to manipulate species composition in favour of the desirable components in pastures,but whether grazing is rested or strategically applied depends on the management goal,sizes of populations of the IAP and more desirable species,and climatic and edaphic conditions.Conclusions:Based on our findings,we integrated these relationships to develop a testable framework for managing IAPs with strategic grazing that considers both the current state of the plant community and the desired future state—i.e.the application of the principles behind reclamation,rehabilitation,restoration or all three—over time.展开更多
Aims Supratidal plant communities fulfil a vital role in coastal protec-tion,but despite an increased likelihood of seawater flooding resulting from anthropogenic climate change,we understand little about how tidal in...Aims Supratidal plant communities fulfil a vital role in coastal protec-tion,but despite an increased likelihood of seawater flooding resulting from anthropogenic climate change,we understand little about how tidal inundation affects these habitats or interactions between their component species.Our aim was to determine how three common coastal grassland species responded to simulated seawater flooding and how subsequent changes to their ecophysi-ology,growth and survival might affect plant-plant interactions in mixed assemblages.Methods Seeds of three widely distributed European coastal grassland species(Leontodon autumnalis Asteraceae,Plantago lanceo-lata Plantaginaceae and Trifolium pratense Fabaceae)were collected from a coastal grassland site in South West England.in Experiment 1,we quantified changes in leaf ion(K^(+),Na^(+),Cl^(−))concentrations as a response to short-duration(0,2,8 or 24 h)immersion in seawater of the root-zone before monitoring longer-term effects on plant survival and growth.in a second experiment,we examined community-level responses by subjecting mixed assemblages of all three species to seawater immersion for(0,12,24 or 96 h).Important Findings When grown individually,one species(Trifolium)had markedly reduced survival with increasing soil immersion time,but a con-sistent decline in plant growth for all species with flooding dura-tion was most likely linked to osmotic and ionic stresses caused by salt ion accumulation.in mixed assemblages,all species suffered increased mortality and reduced growth following seawater flood-ing,although the relative contribution of one species(Leontodon)to total biomass increased in flooded microcosms.We thus demon-strate a number of species-specific responses to simulated seawater flooding and show that when grown together,interactions between plants are altered as a consequence.We argue that variation in the responses of component plant species will dictate how coastal plant communities respond to,and recover from,expected changes in sea levels and transient floods following storm surge events.Such infor-mation is vital in order to predict future impacts of seawater floods on supratidal vegetation.展开更多
Due to questions raised regarding authorship of the article entitled“Evolutionary thinking in restoration under global environmental changes”by Chuanhua Wang,Tianhua He and Fangqing Chen,published online:February 13...Due to questions raised regarding authorship of the article entitled“Evolutionary thinking in restoration under global environmental changes”by Chuanhua Wang,Tianhua He and Fangqing Chen,published online:February 13,2013(http://jpe.oxfordjournals.org/content/early/2013/02/05/jpe.rtt005.full)in Journal of Plant Ecology(DOI:10.1093/jpe/rtt005),the editors have requested it be retracted from the journal.展开更多
基金supported by the National 973 Program of China (2011CB100501)the National 863 Program of China(2013AA102901)+1 种基金the Special Fund for Agro-Scientific Research in the Public Interest, China (201203077)the Science and Technology Project for Grain Production, China (2011BAD16B15)
文摘Increasing basic farmland soil productivity has significance in reducing fertilizer application and maintaining high yield of crops. In this study, we defined that the basic soil productivity （BSP） is the production capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local environment and field management. Based on 22-yr （1990-2011） long-term experimental data on black soil （Typic hapludoll） in Gongzhuling, Jilin Province, Northeast China, the decision support system for an agro-technology transfer （DSSAT）-CERES-Maize model was applied to simulate the yield by BSP of spring maize （Zea mays L.） to examine the effects of long-term fertilization on changes of BSP and explore the mechanisms of BSP increasing. Five treatments were examined： （1） no-fertilization control （control）; （2） chemical nitrogen, phosphorus, and potassium （NPK）; （3） NPK plus farmyard manure （NPKM）; （4） 1.5 time of NPKM （1.5NPKM） and （5） NPK plus straw （NPKS）. Results showed that after 22-yr fertilization, the yield by BSP of spring maize significantly increased 78.0, 101.2, and 69.4% under the NPKM, 1.5NPKM and NPKS, respectively, compared to the initial value （in 1992）, but not significant under NPK （26.9% increase） and the control （8.9% decrease）. The contribution percentage of BSP showed a significant rising trend （P〈0.05） under 1.5NPKM. The average contribution percentage of BSP among fertilizations ranged from 74.4 to 84.7%, and ranked as 1.5NPKM〉NPKM〉NPK〉NPKS, indicating that organic manure combined with chemical fertilizers （I.5NPKM and NPKM） could more effectively increase BSP compared with the inorganic fertilizer application alone （NPK） in the black soil. This study showed that soil organic matter （SOM） was the key factor among various fertility factors that could affect BSP in the black soil, and total N, total P and/or available P also played important role in BSP increasing. Compared with the chemical fertilization, a balanced chemical plus manure or straw fertilization （NPKM or NPKS） not only increased the concentrations of soil nutrient, but also improved the soil physical properties, and structure and diversity of soil microbial population, resulting in an iincrease of BSP. We recommend that a balanced chemical plus manure or straw fertilization （NPKM or NPKS） should be the fertilization practices to enhance spring maize yield and improve BSP in the black soil of Northeast China.
基金Financial supports are from the National Basic Research Program of China (2011CB100501)the National Natural Science Foundation of China (41171239, 41371247)the Project of Aid of Science and Technology in Xinjiang, China (201191140)
文摘Soil organic carbon （SOC） and soil Olsen-P are key soil fertility indexes but information on their relationships is limited particularly under long-term fertilization. We investigated the relationships between SOC and the percentage of soil Olsen-P to total P （PSOPTP） under six different 15-yr （1990-2004） long-term fertilizations at two cropping systems in northern China. These fertilization treatments were （1） unfertilized control （control）; （2） chemical nitrogen （N）; （3） N plus chemical P （NP）; （4） NP plus chemical potassium （NPK）; （5） NPK plus animal manure （NPKM） and （6） high NPKM （hNPKM）. Compared with their initial values in 1989 at both sites, during the 1 lth to 15th fertilization years annual mean SOC contents were significantly increased by 39.4-47.0% and 58.9-93.9% at Gongzhuling, Jilin Province, and Urumqi, Xinjiang, China, under the two NPKM fertilizations, respectively, while no significant changes under the no-P or chemical P fertilization. During the 1 lth to 15th fertilization years, annual mean PSOPTP was respectively increased by 2.6-4.2 and 5.8-14.1 times over the initial values under the two chemical P fertilizations and the two NPKM fertilizations, but was unchanged in their initial levels under the two no-P fertilizations at both sites. Over the 15-yr long-term fertilization SOC significantly positively correlated with PSOPTP （r^2=0.55-0.79, P〈0.01）. We concluded that the combination of chemical P plus manure is an effective way to promote SOC accumulation and the percentage of soil Olsen-P to total P at the two mono-cropping system sites in northern China.
基金the Visiting Scientist Scholarship and Wheat Breeding Research Project of Hebei Province, China (06220114D)
文摘The availability of elite germplasm resources with high yield and quality potentials is very important for development of cultivars in wheat. Thus, seeking such resources has been the continuous effort of breeder community. In this study, genetic analysis of a novel resource, Triticum spelta line CSCR6, from Australia was made by use of a recombination inbred line （RIL） population of 82 individuals from the cross between CSCR6 and another Australian hexaploid wheat cultivar, Lang. Data of a multiple environmental test was employed to genetically dissect quantitative trait loci （QTL） for agronomic traits such as plant height （PH）, spike length （SL）, spikelet per spike （SPI）, grain number per spike （GNS） and thousand grains weight （TGW） and for quality traits including grain protein content （GPC）, gluten content （GC）, grain hardness （GH）, falling number （FN） and sedimentation value （SV）. A 24 QTLs with additive effects were detected for all the investigated traits, and were located on chromosomes 1B, 1D, 2B, 3A, 3B, 3D, 4B, 5A, 5B, 7A, and 7B, respectively. Some QTLs located on 2B and 4B showed higher explanation of phenotypic variances and were not obviously interacted with environment. A QTL in the marker interval of wPT-5334-wPT-4918 （near the locus barc 0199） on 4B gave the highest contribution ratio of 30.76% on PH, while Qgpc-4B and Qgc-4B gave 13.07 and 14.70% contribution ratio on GPC and GC, respectively. Qph-2B, Qgns-2B, and Qgpc-2B showed 13.36, 10.00, and 10.79% contribution ratio on PH, GNS and GPC, respectively. Also, a QTL on 5A, Qsl- 5A, could explain 25.12% of phenotypic variance on SL. For most of agronomic and quality traits, CSCR6 alleles produced increase effects. The fact that a number of loci affecting the investigated traits were detected in T. spelta line CSCR6 revealed that it could offer a new opportunity for the manipulation of these traits in wheat breeding programs.
基金the DUS Project (Guidelines for the Conduct of Tests for Distinctness,Uniformity and Stability for Wintersweet,2006002) for funding assistance
文摘To classify the Chinese wintersweet（Chimonanthus praecox） cultivars and to study their evolution based on pollen morphology.Pollens of 12 representative wintersweet cultivars were examined by scanning electron microscopy（SEM）.Q-cluster analysis was carried out based on the observation results.Results are as follows：（1） The pollen grains were 2lobed circular in polar view,elliptic in equatorial view.The pollen shapes were spheroidal or super-spheroidal by P/E（polar axis length/equatorial axis length） criteria.（2） According to pollen exine ornamentation,it was indicated that white wintersweet is most original.Yellow floral group could be classified into three subgroups：purple-hearted,halo-hearted and yellow-hearted type.Their evolutionary relationship was purple-hearted halo-hearted yellow-hearted.（3） Different wintersweet cultivars showed a different exine sculpture.Palynological analysis could be used in the classification of wintersweet cultivars.The result of cluster analysis indicated that the cultivars could be classified into three groups with a similarity coefficient of 0.41.Each group had similar pollen exine sculpture.It was found that the palynological classification coincided well with morphological classification.Our results support the suggestion that purple streaks or patches of inner-petals should be served as the first-order criteria in wintersweet classification.
基金supported by the projects from the National Natural Science Foundation of China(31971937 and 31970243)the Key Projects of Scientific and Technological Activities for Overseas Students of Sichuan Province,Chinathe Applied Basic Research Programs of Science and Technology Department of Sichuan Province,China(2020YJ0140)。
文摘Uppermost-internode diameter(UID)is a key morphological trait associated with spike development and yield potential in wheat.Our understanding of its genetic basis remains largely unknown.Here,quantitative trait loci(QTLs)for UID with high-density genetic maps were identified in five wheat recombinant inbred line(RIL)populations.In total,25 QTLs for UID were detected in five RIL populations,and they were located on chromosomes 1A,1D(3 QTL),2B(2),2D(3),3B,3D,4A,4B(3),4D,5A(5),5B(2),6B,and 7D.Of them,five major and stable QTLs(QUid.sau-2CN-1D.1,QUid.sau-2SY-1D,QUid.sau-QZ-2D,QUid.sau-SC-3D,and QUid.sau-AS-4 B)were identified from each of the five RIL populations in multiple environments.QUid.sau-2CN-1D.1,QUid.sau-2SY-1D and QUid.sau-SC-3D are novel QTLs.Kompetitive Allele Specific PCR(KASP)markers tightly linked to them were further investigated for developing near-isogenic lines(NILs)carrying the major loci.Furthermore,candidate genes at these intervals harboring major and stable QTLs were predicted,and they were associated with plant development and water transportation in most cases.Comparison of physical locations of the identified QTL on the‘Chinese Spring’reference genome showed that several QTLs including two major ones,QUid.sau-2CN-1D.1 and QUid.sau-2 SY-1 D,are likely allelic confirming their validity and effectiveness.The significant relationships detected between UID and other agronomic traits and a proper UID were discussed.Collectively,our results dissected the underlying genetic basis for UID in wheat and laid a foundation for further fine mapping and map-based cloning of these QTLs.
文摘Natural regeneration is a critical component of forest ecosystems sustainability. Local extinction can occur without adequate regenerationor seedling recruitment prior to adult senescence. The urban and peri-urban environment is particularly challenging for recruitment. For example, although many forest species have specific requirements involving fire events, few opportunities associated with fire exist in contemporary urban and peri-urban environments. For our study species, Eucalyptus gomphocephala, en masse recruitment can occur in ashbeds following a hot fire. However, this may not occur following low-intensity, fuel reduction burns that are prescribed for many E. gomphocephala woodlands and forests. Nevertheless, ashbeds could be created by constructing and burning coarse woody debris (CWD) piles. In a series of collaborative case studies involving community groups, NGOs and Local and State Government agencies, we investigated whether seedling recruitment could be facilitated through broadcast seeding after: a) creating CWD piles prior to a low intensity, prescribed burn;b) naturally-occurring ashbeds following a hot summer wildfire;and c) creating CWD piles and then burning the piles only. We found that regeneration of this post-fire, canopy gap regenerator can be facilitated by broadcast seeding naturally occurring or created ashbeds. However, it seems that protection from seed harvesters and herbivores is vital. These case studies provide tools that can be used to preserve the natural demographics in populations with specific regeneration requirements in a range of environments by leveraging natural recruitment processes and community involvement. Importantly, it is the conservation of these urban and peri-urban ecosystems that will be vital in maintaining connection between people and the environment into the future.
基金supported by the China National Science and Technology Pillar Program in the Eleventh Five-Fear Plan (No. 2007BAD87B10)
文摘A pot experiment was conducted to examine the activity of antioxidant enzymes, the content of malondialdehyde （MDA）, proline and protein, and Cd uptake in different rice cultivars exposed to Cd （0, 1 and 5 mg/kg） in the presence of organic acids and ethylenediamine tetraacetic acid （EDTA）. The results showed the increase in activity of dismutase （SOD）, contents of proline and protein but a decline in activities of peroxidase （POD） and catalase （CAT）, and MDA content for cultivars Xiushui63 and IIyou527. The resistance to Cd was higher in Xiushui63 than that in IIyou527 under the same Cd treatment. Cadmium contents in grain, straw and roots of both cultivars were markedly reduced in the presence of organic acids and EDTA. Grain Cd contents was the highest for plants treated with organic acids, followed by organic acids ＋ 1/2EDTA, and the lowest with EDTA; Cd contents in straw and root were the lowest for plants treated with organic acids, followed by organic acids ＋ 1/2EDTA, and the highest with EDTA treatment when exposed to Cd.
基金Financial supports are from the National Natural Science Foundation of China (41001175)the National Basic Research Program of China (2011CB100501)the Special Basic Research Fund for Public Institutes in China (202-2)
文摘Improving nitrogen use efficiency （NUE） and decreasing N loss are critical to sustainable agriculture. The objective of this research was to investigate the effect of various fertilization regimes on yield, NUE, N agronomic efficiency （NAE） and N loss in long-term （16- or 24-yr） experiments carried out at three rice-wheat rotation sites （Chongqing, Suining and Wuchang） in subtropical China. Three treatments were examined： sole chemical N, N＋phosphorus （NP）, and NP＋potassium （NPK） fertilizations. Grain yields at three sites were significantly increased by 9.3-81.6% （rice） and 54.5-93.8% （wheat） under NP compared with N alone, 1.7-9.8% （rice） and 0-17.6% （wheat） with NPK compared with NP. Compared to NP, NUE significantly increased for wheat at Chongqing （9.3%） and Wuchang （11.8%）, but not at Suining, China. No changes in NUE were observed in rice between NP and NPK at all three sites. The rice-wheat rotation＇s NAE was 3.3 kg kg1 higher under NPK than under NP at Chongqing, while NAE was similar for NP and NPK at Suining and Wuchang. We estimated that an uptake increase of 1.0 kg N hal would increase 40 kg rice and 30 kg wheat ha-1. Nitrogen loss/input ratios were -60, -40 or -30% under N, NP or NPK at three sites, indicating significant decrease of N loss by P or PK additions. We attribute part of the increase in NUE soil N accumulation which significantly increased by 25-55 kg ha-1 yr1 under NPK at three sites, whereas by 35 kg ha-1 yr-1 under NP at Chongqing only. This paper illustrates that apply P and K to wheat, and reduce K application to rice is an effective nutrient management strategy for both the NUE improvement and N losses reduction in China.
文摘Aims Mycorrhizas(fungal roots)play vital roles in plant nutrient acquisition,performance and productivity in terrestrial ecosystems.Arbuscular mycorrhizas(AM)and ectomycorrhizas(EM)are mostly important since soil nutrients,including NH+4,NO3 and phosphorus,are translocated from mycorrhizal fungi to plants.Individual species,genera and even families of plants could be interconnected by mycorrhizal mycelia to form common mycorrhizal networks(CMNs).The function of CMNs is to provide pathways for movement or transfer of nutrients from one plant to another.In the past four decades,both ^(15)N external labeling or enrichment(usually expressed as atom%)and ^(15)N naturally occurring abundance(d^(15)N,&)techniques have been employed to trace the direction and magnitude of N transfer between plants,with their own advantages and limitations.Important Findings The heavier stable isotope ^(15)N is discriminated against 14N during biochemical,biogeochemical and physiological processes,due to a greater atomic mass.In general,non-N2-fixing plants had greater d^(15)N values than N2-fixing(;0&)ones.Foliar d^(15)N often varied by 5 to 10&in the order:non-mycorrhizas/AMs>EMs>ericoid mycorrhizas.Differences in d^(15)N(&)or ^(15)N(atom%)values could thus provide N transfer information between plants.A range of between 0 to 80%of one-way N transfer had been observed from N2-fixing mycorrhizal to non-N2-fixing mycorrhizal plants,but generally less than or around 10%in the reverse direction.Plant-to-plant N transfer may provide practical implications for plant performance in N-limited habitats.Considering that N translocation or cycling is crucial,and the potential benefits of N transfer are great in both agricultural and natural ecosystems,more research is warranted on either oneway or two-way N transfers mediated by CMNs with different species and under field conditions.
基金provided by the National 973 Program of China(2011CB100501 and 2014CB441001)the National Natural Science Foundation of China(41071200)
文摘Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems. We analyzed the historical （1990-2005） observations on four agricultural long-term experiments in China （Changping, Chongqing, Gongzhuling and Qiyang） under four different fertilizations, i.e., no-fertilizer （control）, sole chemical nitrogen fertilizer （FN）, sole chemical phosphorous and potassium fertilizers （FPK） and chemical nitrogen, phosphorous and potassium fertilizers （FNPK）. The significant decline in topsoil pH was caused not only by chemical N fertilization （0.29 and 0.89？pH at Gongzhuling and Qiyang, respectively） but also by chemical PK fertilization （0.59？pH at Gongzhuling）. The enhancement of available nutrients in the topsoil due to long-term direct nutrients supply with chemical fertilizers was in the descending order of available P （168-599%）〉available K （16-189%）〉available N （9-33%）. The relative rate of soil pH decline was lower under long-term judicious chemical fertilization （-0.036-0.034 ？pH yr-1） than that under long-term sole N or PK fertilization （0.016-0.086 ？pH yr-1）. Long-term judicious chemical fertilization with N, P and K elements decreases the nutritional limitation to normal crop growth, under which more N output was distributed in biomass removal rather than the loss via nitrate leaching. We concluded that the N distribution percentage of nitrate leaching to biomass removal might be a suitable indicator to the sensitivity of agricultural ecosystems to acid inputs.
基金This work was supported by a grant from the Australian Research Council[DP1094413]awarded to M.M.M.and R.J.H.
文摘Aims Despite acknowledgement that interactions among native and exotic species are important for determining the structure and diversity of novel communities,directed experiments using mul-tiple exotics from the same system are rare.Recent observational studies have highlighted distinct ways that exotic species interface with resident natives across invaded communities.The correlative nature of these studies,however,has provided few details about the mechanisms driving distinct interaction outcomes within the same communities.Our aim was to determine how three exotic annual plant species with distinct relationships with local plant diversity impact the performance of a co-occurring native annual in the York gum-jam woodlands of Western Australia.Methods We grew species in experimental communities in growth chambers at varying total planting densities to assess how interaction out-comes varied among natives and exotics across a gradient of com-petition intensity.We measured a variety of performance responses,including survival,biomass and population-level and individual-level reproductive investment.Important Findings Overall,the effects of interspecific versus intraspecific competi-tion on performance varied with the identity and density of exotic competitors.The exploitative exotic grass Bromus madritensis was dominant in polyculture,whereas the diminutive grass Pentameris airoides conferred weak intraspecific competition and interspe-cific facilitation on native Waitzia nitida.The exotic broadleaf forb,Hypochaeris glabra,suppressed growth and survival of W.nitida,while W.nitida had weakly negative,neutral or positive effects on all exotics.These outcomes highlight the complexity of interac-tions impacting the diversity,stability and structure of novel plant communities.As few of these communities contain a single exotic species,understanding the competitive dynamics occurring in diverse novel communities is critical for their conservation and restoration.
基金supported by the National Natural Science Foundation of China (Grant No. 41001175) the 11th Five-Year Key Planning Program of China for Science and Technology,Ministry of Science and Technology of China (Grant No. 2006BAD02A14)
文摘The significance of mycorrhizas(fungal roots in 90% of land plants) in plant nutrient acquisition and growth,element biogeo-chemical cycling and maintaining of terrestrial ecosystem structures has been globally established for more than 120 years.Great progress in mycorrhizal research in the past 60 years(1950-2009,1981-2009 in particular) has also been made across China,particularly in the mainland,Hong Kong and Taiwan.For instance,a total of 20 new and ~120 records of arbuscular mycorrhizal(AM) fungal species,30 new and ~800 records of ectomycorrhizal(EM) fungal species,a dozen of new and ~100 records of orchid mycorrhizal(OM) fungal species have been isolated by morphological observation and/or molecular identification in China since the 1950s.Great accomplishment has also been made in the following area,including fungal species richness and genetic structure,relationships between species composition and plant taxa,effects of mycorrhizal fungi on plant nutrient uptake and growth,resistances to pathogens and interactions with other soil microorganisms,potential of mycorrhizal fungi in phytoremediation and/or land reclamation,alterations of enzymatic activities in mycorrhizal plants,and elevated CO2 and O3 on root colonization and species diversity.Unfortunately,the international community cannot easily appreciate almost all Chinese mycorrhizal studies since the vast majority of them have been published in Chinese and/or in China-based journals.The aim of this review is to make a comprehensive exposure of the past and present China's major mycorrhizal research to the whole world,and then to suggest potential directions for the enhancement of future mycorrhizal research within and/or between the Chinese and international mycorrhizal community.
基金supported by the National Natural Science Foundation of China(31070434,30592005)the Knowledge Innovation Program of the Chinese Academy of Sciences(KSCX2-EW-J-6)
文摘Arbuscular mycorrhizal(AM) fungi form mutualistic symbioses with most plant species and play important roles in ecosystems.Knowledge of the response of AM fungi to temperature change will improve our understanding of the function of AM fungal community under global climate change scenarios in ecosystems.The effects of constant warming on AM fungal communities have been investigated previously,but responses to asymmetrical warming over 24-h periods have never been documented in natural ecosystems.In this study,we examined AM fungal communities in a full factorial design including day-time and night-time warming in a semiarid steppe in northern China.Day-time and 24-h warming,but not night-time warming,significantly increased AM fungal spore density.In contrast,none of the three warming regimes had a significant effect on AM fungal extra radical hyphal density.Atotal of 161 operational taxonomic units(OTUs) of AM fungi were recovered by 454 pyrosequencing of 18 S r DNA.Day-time,night-time,and 24-h warming all significantly increased AM fungal OTU richness.Some AM fungal OTUs showed a significant bias toward day-time,night-time or24-h warming.The AM fungal community composition was significantly affected by night-time warming,but not by day-time and 24-h warming.Our finding highlighted different responses of AM fungal spore density and community composition to asymmetrical warming.This study might improve our understanding of ecosystem functioning of AM fungal community under global climate change scenarios in a semiarid steppe ecosystem.
基金Supported by the National Basic Research Program (973 program) of China (Nos. 2011CB100501 and 2007CB309108)the National Natural Science Foundation of China (No. 41071200)
文摘Sustainable potassium （K） management at different soil sites requires understanding the relationships between crop productivity and long-term K fertilizations on a regional or national scale. We analyzed responses of grain yield of wheat （Triticum aestivurn L.） and maize （Zea mays L.）, K efficiency, and partial balance （difference between K input through fertilizer and K output in the aboveground biomass） during 15- （1990-2005） or 18-year （1990-2008） K fertilizations at five distinctive agroecologicai zones across China. Compared to the inorganic nitrogen （N） and phosphorus （P） fertilization, the inorganic NPK fertilization significantly increased grain yields of wheat （21%） and maize （16% 72%） at Qiyang and Changping, where soils have low exchangeable and non-exchangeable K contents, but not at Uriimqi, Yangling and Zhengzhou, where soils have a high exchangeable and non-exchangeable K and/or low N/K ratio in crop plants. Compared to the inorganic NPK fertilization, the inorganic NPK （30% N） and organic manure （70~~ N） fertilization （NPKM） increased grain yields of wheat （14%-40%） and maize （9%-6170） at four sites, but not at Zhengzhou. For a productivity of wheat at 2-5 t ha-1 or maize at 3-6 t ha 1, 13-26 or 9-17 kg K ha 1 were required to produce 1.0 t wheat or maize. The NP fertilization resulted in the lowest negative partial K balance and accumulated 52 kg K ha-1 year-1 less than the NPK fertilization, which accumulated 28 kg ha 1 year-1 less K than the NPKM fertilization. A re-evaluation of the site-specific fertilization effects on N/K ratio in crop plants and soil K accumulation under current NPK and NPKM t＇ertilization is urgently needed to increase both crop yield and K use efficiency at different agroecologicai zones across China.
文摘Two new types of signaling compounds have been discovered in wildfire smoke due to their ability to stimulate seed germination. The first discovered were karrikins, which share some structural similarity with the strigol- actone class of plant hormones, and both signal through a common F-box protein. However, karrikins and strigolactones operate through otherwise distinct signaling pathways, each distinguished by a specific a/13 hydrolase protein. Genetic analysis suggests that plants contain endogenous compounds that signal specifically through the karrikin pathway. The other active compounds discovered in smoke are cyanohydrins that release germination-stimulating cyanide upon hydrolysis. Cyanohydrins occur widely in plants and have a role in defense against other organisms, but an additional role in endogenous cyanide signaling should also now be considered.
基金Supported by the National High Technology Research and Development Program (863 Program) of China (No. 2007AA091701)the National Natural Science Foundation of China (No. 30870138)
文摘Arbuscular mycorrhizal （AM）-mediated plant physiological activities could contribute to plant salt tolerance. However, the biochemical mechanism by which AM fungi enhance salt tolerance of halophytie plants is unclear. A pot experiment was conducted to determine whether salt tolerance of the C3 halophyte Suaeda salsa was enhanced by the AM fungus Glomus rnosseae. When 60-day-old S. salsa seedlings were subjected to 400 mmol L-1 NaC1 stress for 35 days, plant height, number of leaves and branches, shoot and root biomass, and root length of G. mosseae-colonized seedlings were significantly greater than those of the nonmycorrizal seedlings. Leaf superoxide dismutase （SOD） activity at all sampling times （weekly for 35 days after salt stress was initiated） and leaf catalase （CAT） activity at 2 and 3 weeks after salt stress was initiated were also significantly enhanced in G. mosseae-colonized S. salsa seedlings, while the content of leaf malondialdehyde （MDA）, a product of membrane lipid peroxidation, was significantly reduced, indicating an alleviation of oxidative damage. The corresponding leaf isoenzymes of SOD （Fe-SOD, Cu/Zn-SOD1, and Cu/Zn-SOD2） and CAT （CAT1 and CAT2） were also significantly increased in the mycorrhizal seedlings after 14 days of 400 mmol L-1 NaC1 stress. Our results suggested that G. rnosseae increased salt tolerance by increasing SOD and CAT activities and forming SOD and CAT isoforms in S. salsa seedlings.
基金Thank you to Southwell and Reid for granting us permission to use their figure.Jodi Price was funded by the ARC Centre for Excellence for Environmental Decisions.
文摘Introduction:Novel ecosystems that contain new combinations of invasive alien plants(IAPs)present a challenge for managers.Yet,control strategies that focus on the removal of the invasive species and/or restoring historical disturbance regimes often do not provide the best outcome for long-term control of IAPs and the promotion of more desirable plant species.Methods:This study seeks to identify the primary drivers of grassland invasion to then inform management practices toward the restoration of native ecosystems.By revisiting both published and unpublished data from experiments and case studies within mainly an Australian context for native grassland management,we show how alternative states models can help to design control strategies to manage undesirable IAPs by manipulating grazing pressure.Results:Ungulate grazing is generally considered antithetical to invasive species management because in many countries where livestock production is a relatively new disturbance to grasslands(such as in Australia and New Zealand as well as Canada and the USA),selective grazing pressure may have facilitated opportunities for IAPs to establish.We find that grazing stock can be used to manipulate species composition in favour of the desirable components in pastures,but whether grazing is rested or strategically applied depends on the management goal,sizes of populations of the IAP and more desirable species,and climatic and edaphic conditions.Conclusions:Based on our findings,we integrated these relationships to develop a testable framework for managing IAPs with strategic grazing that considers both the current state of the plant community and the desired future state—i.e.the application of the principles behind reclamation,rehabilitation,restoration or all three—over time.
文摘Aims Supratidal plant communities fulfil a vital role in coastal protec-tion,but despite an increased likelihood of seawater flooding resulting from anthropogenic climate change,we understand little about how tidal inundation affects these habitats or interactions between their component species.Our aim was to determine how three common coastal grassland species responded to simulated seawater flooding and how subsequent changes to their ecophysi-ology,growth and survival might affect plant-plant interactions in mixed assemblages.Methods Seeds of three widely distributed European coastal grassland species(Leontodon autumnalis Asteraceae,Plantago lanceo-lata Plantaginaceae and Trifolium pratense Fabaceae)were collected from a coastal grassland site in South West England.in Experiment 1,we quantified changes in leaf ion(K^(+),Na^(+),Cl^(−))concentrations as a response to short-duration(0,2,8 or 24 h)immersion in seawater of the root-zone before monitoring longer-term effects on plant survival and growth.in a second experiment,we examined community-level responses by subjecting mixed assemblages of all three species to seawater immersion for(0,12,24 or 96 h).Important Findings When grown individually,one species(Trifolium)had markedly reduced survival with increasing soil immersion time,but a con-sistent decline in plant growth for all species with flooding dura-tion was most likely linked to osmotic and ionic stresses caused by salt ion accumulation.in mixed assemblages,all species suffered increased mortality and reduced growth following seawater flood-ing,although the relative contribution of one species(Leontodon)to total biomass increased in flooded microcosms.We thus demon-strate a number of species-specific responses to simulated seawater flooding and show that when grown together,interactions between plants are altered as a consequence.We argue that variation in the responses of component plant species will dictate how coastal plant communities respond to,and recover from,expected changes in sea levels and transient floods following storm surge events.Such infor-mation is vital in order to predict future impacts of seawater floods on supratidal vegetation.
文摘Due to questions raised regarding authorship of the article entitled“Evolutionary thinking in restoration under global environmental changes”by Chuanhua Wang,Tianhua He and Fangqing Chen,published online:February 13,2013(http://jpe.oxfordjournals.org/content/early/2013/02/05/jpe.rtt005.full)in Journal of Plant Ecology(DOI:10.1093/jpe/rtt005),the editors have requested it be retracted from the journal.
