Application of slow-release fertilizer(SF)is a nutrient-management measure aimed at improving maize nutrient use and yield and saving labor cost.One-time application of SF at sowing usually results in nutrient deficie...Application of slow-release fertilizer(SF)is a nutrient-management measure aimed at improving maize nutrient use and yield and saving labor cost.One-time application of SF at sowing usually results in nutrient deficiency during the post-silking stage,owing to the long growth period of spring maize.This study was conducted to investigate the effects on spring maize of SF application stage(zero,three-,and six-leaf stages,designated as SF0,SF3,and SF6,respectively)on grain yield,total soil rhizosphere nitrogen(N)content,and root activity,in comparison with the conventional fertilization mode(CF,application of compound fertilizer at sowing time,and topdressing urea at six-leaf and tasseling stages)at the same fertilization level as the control.Compared with no fertilization(F0)and CF,SF increased grain number and weight.The maize cultivars Suyu 30(SY30)and Jiangyu 877(JY877)produced the highest grain yield and net return under SF6 treatment over the three years.SF6 increased enzymatic activities including oxidoreductase,hydrolase,transferase,and lyase in rhizosphere soil at silking(R1)and milking stages(R3).SF6 increased the total N contents of rhizosphere soil by 7.1%at R1 and 9.2%R3 stages compared with SF0.The activities of antioxidant enzymes in roots were increased under SF6 treatments at R1and R3.The mean root activities of SF0,SF3,and SF6 increased by 7.1%,12.8%,and 20.5%compared with CF at R1 and by 8.8%,13.0%,and 23.5%at R3.Delaying the application time of SF could increase grain yield by increasing total N content of rhizosphere soil,delaying root senescence,and increasing root activity at the late reproductive stage.Applying SF at the six-leaf stage is recommended as an effective fertilization strategy for the sustainable production of spring maize in southern China.展开更多
Background:The diversity of resource acquisition strategies of plant roots determines the species coexistence patterns to a certain extent.However,few root physiological traits have been investigated,such as root phos...Background:The diversity of resource acquisition strategies of plant roots determines the species coexistence patterns to a certain extent.However,few root physiological traits have been investigated,such as root phosphatase activity(PA)that affects plant phosphorus(P)uptake.Methods:Root PA and classical root functional traits were investigated for 21 coexisting species in a deciduous broad-leaved forest in warm temperate-subtropical transition zone,China.We analyzed the root order variation of absorptive fine root PA,clarified the attribution of root PA in root economic space(RES)and the different P acquisition strategies of co-occurring species based on the multidimensional RES theory,and determined the dominant factors affecting interspecific variation in root PA.Results:There was no distinct pattern of PA variation with root order in the first three root orders of absorptive fine roots,and root PA was constrained by phylogeny.Root PA is a competitive trait affiliated with the conservation gradient in RES.The tight linkages among root PA,mycorrhizal colonization,diameter,specific root length,and nitrogen concentration suggested trade-offs among P acquisition strategies of co-occurring species,i.e.species with long and fine roots acquire inorganic P by actively exploring the soil and secreting phosphatase to mineralize and hydrolyze organic P,while species with short and thick roots obtain P mainly by investing C in mycorrhizal partners.Conclusions:Collectively,our study provides an insight into the forest species coexistence in climatic transition zones,i.e.species coexistence mechanisms based on diverse phosphorus acquisition strategies.展开更多
Utilizing the heterosis of indica/japonica hybrid rice(IJHR)is an effective way to further increase rice grain yield.Rational application of nitrogen(N)fertilizer plays a very important role in using the heterosis of ...Utilizing the heterosis of indica/japonica hybrid rice(IJHR)is an effective way to further increase rice grain yield.Rational application of nitrogen(N)fertilizer plays a very important role in using the heterosis of IJHR to achieve its great yield potential.However,the responses of the grain yield and N utilization of IJHR to N application rates and the underlying physiological mechanism remain elusive.The purpose of this study was to clarify these issues.Three rice cultivars currently used in rice production,an IJHR cultivar Yongyou 2640(YY2640),a japonica cultivar Lianjing 7(LJ-7)and an indica cultivar Yangdao 6(YD-6),were grown in the field with six N rates(0,100,200,300,400,and 500 kg ha^(-1))in 2018 and 2019.The results showed that with the increase in N application rates,the grain yield of each test cultivar increased at first and then decreased,and the highest grain yield was at the N rate of 400 kg ha^(-1)for YY2640,with a grain yield of 13.4 t ha^(-1),and at 300 kg ha^(-1)for LJ-7 and YD-6,with grain yields of 9.4–10.6 t ha^(-1).The grain yield and N use efficiency(NUE)of YY2640 were higher than those of LJ-7 or YD-6 at the same N rate,especially at the higher N rates.When compared with LJ-7 or YD-6,YY2640 exhibited better physiological traits,including greater root oxidation activity and leaf photosynthetic rate,higher cytokinin content in the roots and leaves,and more remobilization of assimilates from the stem to the grain during grain filling.The results suggest that IJHR could attain both higher grain yield and higher NUE than inbred rice at either low or high N application rates.Improved shoot and root traits of the IJHR contribute to its higher grain yield and NUE,and a higher content of cytokinins in the IJHR plants plays a vital role in their responses to N application rates and also benefits other physiological processes.展开更多
To clarify the optimal water management in large-scale fields under high temperatures at the ripening period,effective water managements during this period for improvement of yield,appearance quality and palatability ...To clarify the optimal water management in large-scale fields under high temperatures at the ripening period,effective water managements during this period for improvement of yield,appearance quality and palatability were investigated.Compared with intermittent irrigation and flooded irrigation,the soil temperature with saturated irrigation remained low throughout the day,and the decrease rate of the bleeding rate of hills was the lowest.These results suggested that the saturated irrigation maintained root activity.For the three irrigation types,the number of spikelets per m2 and 1000-grain weight were similar,however,saturated irrigation resulted in significantly higher rice yield due to improvement in the percentage of ripened grains.The saturated irrigation produced a high percentage of perfect rice grains and thicker brown rice grain,furthermore,the palatability of cooked rice was excellent because protein content and hardness/adhesion ratio were both low.Thus,under high-temperature ripening conditions,soil temperature was lowered and root activity was maintained when applying saturated irrigation after heading time.The results indicated that saturated irrigation is an effective countermeasure against high-temperature ripening damage.展开更多
Background:Soil acidification caused by acid rain(AR)can damage plant roots,which in turn negatively impacts plant health.In response to changing AR types,research efforts to elucidate their specific impacts on plants...Background:Soil acidification caused by acid rain(AR)can damage plant roots,which in turn negatively impacts plant health.In response to changing AR types,research efforts to elucidate their specific impacts on plants have become intense.Methods:For this study,we investigated the effects of simulated sulfuric,nitric,and mixed AR on the root systems of Quercus acutissima Carr.and Cunninghamia lanceolata(Lamb.)Hook.under different acidity levels.Results:As the AR S/N ratio and pH decreased,the height growth rate(HGR),basal diameter growth rate(DGR),total root length(TRL)and total root surface area(TRS)of C.lanceolata decreased,whereas the TRL and TRS of Q.acutissima remained the same.When the NO_(3)^(−)concentration in AR was increased,the root activity,superoxide dismutase(SOD)and catalase(CAT)activities of C.lanceolata roots revealed a downward trend;however,the root activity of Q.acutissima and the peroxidase(POD)activity of C.lanceolata roots revealed an upward trend.Further,redundant analysis and structural equation models indicated that AR pH had a greater impact on the HGR of Q.acutissima than that of C.lanceolata,while the impact of the AR S/N ratio on C.lanceolata growth rates was greater than that of Q.acutissima.Conclusions:Our results suggested that the root systems of different tree species had variable responses to AR,and the AR S/N ratio was an important factor affecting plant root growth.This might facilitate new strategies for the culti‑vation and protection of plantations in the future.展开更多
基金the financial support of the National Key Research and Development Program of China(2016YFD0300109)National Natural Science Foundation of China(32101828,32071958)+3 种基金Natural Science Foundation of Jiangsu Province(BK20200952)the Open Project Program of Joint International Research Laboratory of Agriculture and Agri-Product Safety(JILAR-KF202010)the Jiangsu Agricultural Industry Technology System of China(JATS[2020]444)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Application of slow-release fertilizer(SF)is a nutrient-management measure aimed at improving maize nutrient use and yield and saving labor cost.One-time application of SF at sowing usually results in nutrient deficiency during the post-silking stage,owing to the long growth period of spring maize.This study was conducted to investigate the effects on spring maize of SF application stage(zero,three-,and six-leaf stages,designated as SF0,SF3,and SF6,respectively)on grain yield,total soil rhizosphere nitrogen(N)content,and root activity,in comparison with the conventional fertilization mode(CF,application of compound fertilizer at sowing time,and topdressing urea at six-leaf and tasseling stages)at the same fertilization level as the control.Compared with no fertilization(F0)and CF,SF increased grain number and weight.The maize cultivars Suyu 30(SY30)and Jiangyu 877(JY877)produced the highest grain yield and net return under SF6 treatment over the three years.SF6 increased enzymatic activities including oxidoreductase,hydrolase,transferase,and lyase in rhizosphere soil at silking(R1)and milking stages(R3).SF6 increased the total N contents of rhizosphere soil by 7.1%at R1 and 9.2%R3 stages compared with SF0.The activities of antioxidant enzymes in roots were increased under SF6 treatments at R1and R3.The mean root activities of SF0,SF3,and SF6 increased by 7.1%,12.8%,and 20.5%compared with CF at R1 and by 8.8%,13.0%,and 23.5%at R3.Delaying the application time of SF could increase grain yield by increasing total N content of rhizosphere soil,delaying root senescence,and increasing root activity at the late reproductive stage.Applying SF at the six-leaf stage is recommended as an effective fertilization strategy for the sustainable production of spring maize in southern China.
基金financially supported by the National Natural Science Foundation of China(Nos.32230067,32001171 and 32001120)。
文摘Background:The diversity of resource acquisition strategies of plant roots determines the species coexistence patterns to a certain extent.However,few root physiological traits have been investigated,such as root phosphatase activity(PA)that affects plant phosphorus(P)uptake.Methods:Root PA and classical root functional traits were investigated for 21 coexisting species in a deciduous broad-leaved forest in warm temperate-subtropical transition zone,China.We analyzed the root order variation of absorptive fine root PA,clarified the attribution of root PA in root economic space(RES)and the different P acquisition strategies of co-occurring species based on the multidimensional RES theory,and determined the dominant factors affecting interspecific variation in root PA.Results:There was no distinct pattern of PA variation with root order in the first three root orders of absorptive fine roots,and root PA was constrained by phylogeny.Root PA is a competitive trait affiliated with the conservation gradient in RES.The tight linkages among root PA,mycorrhizal colonization,diameter,specific root length,and nitrogen concentration suggested trade-offs among P acquisition strategies of co-occurring species,i.e.species with long and fine roots acquire inorganic P by actively exploring the soil and secreting phosphatase to mineralize and hydrolyze organic P,while species with short and thick roots obtain P mainly by investing C in mycorrhizal partners.Conclusions:Collectively,our study provides an insight into the forest species coexistence in climatic transition zones,i.e.species coexistence mechanisms based on diverse phosphorus acquisition strategies.
基金grateful for grants from the National Natural Science Foundation of China(32071943)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD-2020-01)+1 种基金the Postgraduate Research and Innovation Program of Jiangsu Province,China(XKYCX17_052)the Top Talent Supporting Program of Yangzhou University,China(2015-01).
文摘Utilizing the heterosis of indica/japonica hybrid rice(IJHR)is an effective way to further increase rice grain yield.Rational application of nitrogen(N)fertilizer plays a very important role in using the heterosis of IJHR to achieve its great yield potential.However,the responses of the grain yield and N utilization of IJHR to N application rates and the underlying physiological mechanism remain elusive.The purpose of this study was to clarify these issues.Three rice cultivars currently used in rice production,an IJHR cultivar Yongyou 2640(YY2640),a japonica cultivar Lianjing 7(LJ-7)and an indica cultivar Yangdao 6(YD-6),were grown in the field with six N rates(0,100,200,300,400,and 500 kg ha^(-1))in 2018 and 2019.The results showed that with the increase in N application rates,the grain yield of each test cultivar increased at first and then decreased,and the highest grain yield was at the N rate of 400 kg ha^(-1)for YY2640,with a grain yield of 13.4 t ha^(-1),and at 300 kg ha^(-1)for LJ-7 and YD-6,with grain yields of 9.4–10.6 t ha^(-1).The grain yield and N use efficiency(NUE)of YY2640 were higher than those of LJ-7 or YD-6 at the same N rate,especially at the higher N rates.When compared with LJ-7 or YD-6,YY2640 exhibited better physiological traits,including greater root oxidation activity and leaf photosynthetic rate,higher cytokinin content in the roots and leaves,and more remobilization of assimilates from the stem to the grain during grain filling.The results suggest that IJHR could attain both higher grain yield and higher NUE than inbred rice at either low or high N application rates.Improved shoot and root traits of the IJHR contribute to its higher grain yield and NUE,and a higher content of cytokinins in the IJHR plants plays a vital role in their responses to N application rates and also benefits other physiological processes.
基金supported by the grants from the Project of the National Agriculture and Food Research Organization Bio-oriented Technology Research Advancement Institution in Japan(the Special Scheme to Create Dynamism in Agriculture,Forestry and Fisheries through Deploying Highly Advanced Technology)(Grant No.shoNavi1000)。
文摘To clarify the optimal water management in large-scale fields under high temperatures at the ripening period,effective water managements during this period for improvement of yield,appearance quality and palatability were investigated.Compared with intermittent irrigation and flooded irrigation,the soil temperature with saturated irrigation remained low throughout the day,and the decrease rate of the bleeding rate of hills was the lowest.These results suggested that the saturated irrigation maintained root activity.For the three irrigation types,the number of spikelets per m2 and 1000-grain weight were similar,however,saturated irrigation resulted in significantly higher rice yield due to improvement in the percentage of ripened grains.The saturated irrigation produced a high percentage of perfect rice grains and thicker brown rice grain,furthermore,the palatability of cooked rice was excellent because protein content and hardness/adhesion ratio were both low.Thus,under high-temperature ripening conditions,soil temperature was lowered and root activity was maintained when applying saturated irrigation after heading time.The results indicated that saturated irrigation is an effective countermeasure against high-temperature ripening damage.
基金funded by the Jiangsu Province Science Foundation for Youths(BK20200785)China Postdoctoral Science Foundation(2018M642260)+2 种基金the National Special Fund for Forestry Scientific Research in the Public Interest(Grant No.201504406)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Jiangsu Agriculture Science and Technology Innovation Fund(Grant No.CX(17)1004)。
文摘Background:Soil acidification caused by acid rain(AR)can damage plant roots,which in turn negatively impacts plant health.In response to changing AR types,research efforts to elucidate their specific impacts on plants have become intense.Methods:For this study,we investigated the effects of simulated sulfuric,nitric,and mixed AR on the root systems of Quercus acutissima Carr.and Cunninghamia lanceolata(Lamb.)Hook.under different acidity levels.Results:As the AR S/N ratio and pH decreased,the height growth rate(HGR),basal diameter growth rate(DGR),total root length(TRL)and total root surface area(TRS)of C.lanceolata decreased,whereas the TRL and TRS of Q.acutissima remained the same.When the NO_(3)^(−)concentration in AR was increased,the root activity,superoxide dismutase(SOD)and catalase(CAT)activities of C.lanceolata roots revealed a downward trend;however,the root activity of Q.acutissima and the peroxidase(POD)activity of C.lanceolata roots revealed an upward trend.Further,redundant analysis and structural equation models indicated that AR pH had a greater impact on the HGR of Q.acutissima than that of C.lanceolata,while the impact of the AR S/N ratio on C.lanceolata growth rates was greater than that of Q.acutissima.Conclusions:Our results suggested that the root systems of different tree species had variable responses to AR,and the AR S/N ratio was an important factor affecting plant root growth.This might facilitate new strategies for the culti‑vation and protection of plantations in the future.
