Pre-harvest water deficit(PHWD)plays an important role in sugar accumulation of citrus fruit.However,the mechanism is not known well.Here,it was confirmed that PHWD promoted sucrose accumulation of citrus fruit,but ha...Pre-harvest water deficit(PHWD)plays an important role in sugar accumulation of citrus fruit.However,the mechanism is not known well.Here,it was confirmed that PHWD promoted sucrose accumulation of citrus fruit,but had limited effect on fructose,glucose and total acid.A sucrose transporter,Cs SUT1,which localizes to the plasma membrane,was demonstrated to function in sucrose transport induced by PHWD.Compared to wild-type,Cs SUT1 overexpression in citrus calli stimulated sucrose,fructose and glucose accumulation,while its silencing in juice sacs reduced sucrose accumulation.Increased sugar accumulation in transgenic lines enhanced plant drought tolerance,and resulted in decreased electrolyte leakage,malondialdehyde and hydrogen peroxide contents,as well as increased superoxide dismutase activity and proline contents.An abscisic acid(ABA)-responsive transcription factor,Cs ABF3,was found with a same expression pattern with Cs SUT1 under PHWD.Yeast one-hybrid,electrophoretic mobility shift assay and dual-luciferase assays all revealed that Cs ABF3 directly bound with the Cs SUT1 promoter by ABA responsive elements.When Cs ABF3 was overexpressed in citrus calli,the sucrose,fructose and glucose concentration increased correspondingly.Further,transgenic studies demonstrated that Cs ABF3 could affect sucrose accumulation by regulating Cs SUT1.Overall,this study revealed a regulation of Cs ABF3 promoting Cs SUT1 expression and sucrose accumulation in response to PHWD.Our results provide a detail insight into the quality formation of citrus fruit.展开更多
This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency(WUE) under alternate wetting and drying(AWD) irrigation than check...This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency(WUE) under alternate wetting and drying(AWD) irrigation than check rice. Two super rice cultivars and two elite check rice cultivars were grown in pots with three soil moisture levels, well watered(WW), moderate water deficit(MWD) and severe water deficit(SWD). Two cultivars, each for super rice and check rice, were grown in field with three irrigation regimes, alternate wetting and moderate drying(AWMD), alternate wetting and severe drying(AWSD) and conventional irrigation(CI). Compared with that under WW, grain yield was significantly decreased under MWD and SWD treatments, with less reduction for super rice than for check rice. Super rice had higher percentage of productive tillers, deeper root distribution, higher root oxidation activity, and greater aboveground biomass production at mid and late growth stages than check rice, especially under WMD and WSD. Compared with CI, AWMD increased, whereas AWSD decreased grain yield, with more increase or less decrease for super rice than for check rice. Both MWD and SWD treatments and either AWMD or AWSD regime significantly increased WUE compared with WW treatment or CI regime, with more increase for super rice than for check rice. The results suggest that super rice has a stronger ability to cope with soil water deficit and holds greater promising to increase both grain yield and WUE by adoption of moderate AWD irrigation.展开更多
Waxy maize is widely cultivated under rainfed conditions and frequently suffers water shortage during the late growth stage.In this study,a pot trial was conducted to examine the effects of post-silking drought on lea...Waxy maize is widely cultivated under rainfed conditions and frequently suffers water shortage during the late growth stage.In this study,a pot trial was conducted to examine the effects of post-silking drought on leaf photosynthesis and senescence and its influence on grain yield.Two waxy maize hybrids,Suyunuo 5(SYN5)and Yunuo 7(YN7),were grown under the control and drought(soil moisture content was 70–80%and 50–60%,respectively)conditions after silking in 2016 and 2017.The decrease in yield was 11.1 and 15.4%for YN7 and SYN5,respectively,owing to the decreased grain weight and number.Post-silking dry matter accumulation was reduced by 27.2%in YN7 and 26.3%in SYN5.The contribution rate of pre-silking photoassimilates transferred to grain yield was increased by 15.6%in YN7 and 10.2%in SYN5,respectively.Post-silking drought increased the malondialdehyde content,but decreased the contents of water,soluble protein,chlorophyll,and carotenoid in the leaves.The weakened activities of enzymes involved in photosynthesis(ribulose-1,5-bisphosphate carboxylase and phosphoenolpyruvate carboxylase)and antioxidant system(catalase,superoxide dismutase and peroxidase)reduced the photosynthetic rate(Pn)and accelerated leaf senescence.The correlation results indicated that reduced Pn and catalase activity and increased malondialdehyde content under drought conditions induced the decrease of post-silking photoassimilates deposition,ultimately resulted in the grain yield loss.展开更多
The content and composition of wheat storage proteins are the major determinants of dough rheological properties and breadmaking quality and are influenced by cultivation conditions.This study aimed to investigate the...The content and composition of wheat storage proteins are the major determinants of dough rheological properties and breadmaking quality and are influenced by cultivation conditions.This study aimed to investigate the effects of water deficit and high N-fertilizer application on wheat storage protein synthesis,gluten secondary structure,and breadmaking quality.Reverse-phase ultrahigh-performance liquid chromatography analysis showed that storage protein and gluten macropolymer accumulation was promoted under both independent applications and a combination of water-deficit and high N-fertilizer treatments.Fourier-transform infrared spectroscopy showed that water deficit and high N-fertilizer treatments generally improved protein secondary structure formation and lipid accumulation,and reduced flour moisture.In particular,high N-fertilizer application increasedβ-sheet content by 10.4%and the combination of water-deficit and high N-fertilizer treatments increased random coil content by 7.6%.These changes in gluten content and secondary structure led to improved dough rheological properties and breadmaking quality,including superior loaf internal structure,volume,and score.Our results demonstrate that moderately high N-fertilizer application under drought conditions can improve gluten accumulation,gluten secondary structure formation,and baking quality.展开更多
Soybeans are one of the most important grain crops worldwide.Water deficit,which seriously affects the yield and quality of soybeans,is the main abiotic stress factor in soybean production.As a follow-up study,the dro...Soybeans are one of the most important grain crops worldwide.Water deficit,which seriously affects the yield and quality of soybeans,is the main abiotic stress factor in soybean production.As a follow-up study,the droughttolerant soybean variant Heinong 44 was analyzed via proteome analysis.Soybean was exposed to water deficit for 0,8,and 24 h,and protein samples were extracted for detection of differentially expressed proteins.Protein sequencing of leaf tissues under water stress yielded a total of 549 differentially expressed proteins:75 and 320 upregulated proteins as well as 70 and 84 downregulated proteins were obtained after 8 and 24 h of water deficit,respectively.Gene Ontology analysis revealed that most of the differentially expressed proteins(DEPs)were involved in catalytic activity,molecular function,and metabolic processes,whereas some of them were involved in photosynthesis,carbon metabolism,and energy metabolism.We also identified some differentially expressed proteins that may be involved in the regulation of water deficit response.Our study provides a theoretical basis for the breeding of drought-resistant soybean varieties.展开更多
Four irrigation treatments were designed with 2, 4, 6 and 8 d intervals to irrigate, respectively. Watering was stopped when the reading of the moisture tension sensor reached zero. The results indicated that glucose ...Four irrigation treatments were designed with 2, 4, 6 and 8 d intervals to irrigate, respectively. Watering was stopped when the reading of the moisture tension sensor reached zero. The results indicated that glucose and fructose content of tomato's fruit were increased but sucrose content was decreased with fruit growth and development. In different stages, carbohydrate content of tomato fruit in the treatment 3 was the highest, in the treatment 2 was higher, and in the other treatments was the lowest. SS(sucrose synthase) activity was decreased but SPS(sucrose phosphate synthase) activity was increased with development of tomato. SS and SPS activity were increased but acid invertase and neutral invertase activity of ripe stage were decreased under deficit irrigation. Glucose and fructose content were increased in leaves of tomato under water deficit.Soluble sugars, organic acid and the ratio of sugar/acid in tomato fruits were increased and dry matter accumulation of plant was enhanced under water deficit. But the growth of fruits upside the plant and its dry matter accumulation were badly affected under water stress.展开更多
To evaluate the response of alfalfa to water deficit(WD) stress, WD-induced candidates were investigated through a proteomic approach. Alfalfa seedlings were exposed to WD stress for 12 and 15 days respectively, follo...To evaluate the response of alfalfa to water deficit(WD) stress, WD-induced candidates were investigated through a proteomic approach. Alfalfa seedlings were exposed to WD stress for 12 and 15 days respectively, followed by 3 days re-watering. Water deficit increased H2O2 content, lipid peroxidation, DPPH(1,1-diphenyl-2-picrylhydrazyl)-radical scavenging activity, and the free proline level in alfalfa roots. Root proteins were extracted and separated by two-dimentional polyacrylamide gel electrophoresis(2-DE). A total of 49 WD-responsive proteins were identified in alfalfa roots; 25 proteins were reproducibly found to be up-regulated and 24 were down-regulated. Two proteins, namely cytosolic ascorbate peroxidase(APx2) and putative F-box protein were newly detected on 2-DE maps of WD-treated plants. We identified several proteins including agamous-like 65, albumin b-32, inward rectifying potassium channel, and auxin-independent growth promoter. The identified proteins are involved in a variety of cellular functions including calcium signaling, abacisic acid(ABA) biosynthesis, reactive oxygen species(ROS) regulation, transcription/ translation, antioxidant/detoxification/stress defense, energy metabolism, signal transduction, and storage. These results indicate the potential candidates were responsible for adaptive response in alfalfa roots.展开更多
Two wheat cultivars(Triticum aestivum L.) were used to evaluate the effects of post-anthesis severe water deficit(SD) on starch content and granule size distribution and their relations with ethylene and spermidine(Sp...Two wheat cultivars(Triticum aestivum L.) were used to evaluate the effects of post-anthesis severe water deficit(SD) on starch content and granule size distribution and their relations with ethylene and spermidine(Spd). Comparison to the well-watered(WW) treatment, SD led to lower Spd and higher 1-aminocylopropane-1-carboxylic acid(ACC) concentrations and ethylene evolution rate(EER) in grains at the critical stage of forming starch granules. Application of Spd or aminoethoxyvinylglycine(AVG) significantly reduced ACC concentration and EER and increased Spd concentration, while ethephon or methylglyoxal-bis(MGBG) had an opposite impact. The volume and surface area distribution of starch granules showed a bimodal curve, while the number distribution exhibited a unimodal curve. SD caused a marked drop in grain weight, grain number and starch content, also led to a significant reduction in the proportion(both by volume and by surface area) of B-type starch granules(<10 μm), with an increase in those of A-type starch granules(>10 μm). Application of Spd or AVG increased the proportion(both by volume and by surface area) of B- type starch granules under SD. Correlation analysis suggested that ethylene and Spd showed an antagonism relation in the f ormation of B-type granules. These results suggested that it would be good for the formation of B-type starch granules to have the physiological traits of higher Spd and lower ACC concentrations and ethylene emission under SD.展开更多
The sustainability of ecosystem restoration of refuse dumps in open-pit coal mines depends on plant species selection,their configuration,and the optimal usage of water resources.This study is based on field experimen...The sustainability of ecosystem restoration of refuse dumps in open-pit coal mines depends on plant species selection,their configuration,and the optimal usage of water resources.This study is based on field experiments in the northern refuse dump of the Heidaigou open-pit coal mine in Inner Mongolia of China established in 1995.Eight plant configurations,including trees,shrubs,grasses,and their combinations,as well as the adjacent community of natural vegetation,were selected.The succession of the revegetated plants,soil water storage,the spatiotemporal distribution of plant water deficits degree and its compensation degree were also studied.Results indicated that the vegetation cover(shrubs and herbaceous cover),richness,abundance,soil nutrients(soil organic matter,N and P),and biological soil crust coverage on the soil surface are significantly influenced by the vegetation configurations.The average soil water storage values in the shrub + grass and grass communities throughout the growing season are 208.69 mm and 206.55 mm,which are the closest to that of in the natural vegetation community(215.87 mm).Plant water deficits degree in the grass and shrub + grass communities were the lowest,but the degrees of water deficit compensation in these configuration were larger than those of the other vegetation configurations.Differences in plant water deficit degree and water compensation among the different configurations were significant(P <0.05).Plant water deficit degrees were predominantly minimal on the surface,increased with increasing soil depth,and remained stable at 80 cm soil depth.The soil moisture compensation in the natural vegetation,shrub + grass,and grass communities changed at 10%,while that in other vegetation communities changed between 20% and 40%.Overall,we conclude that the shrub + grass and grass configuration modes are the optimal vegetation restoration models in terms of ecohydrology for future ecological engineering projects.展开更多
To examine the potential heterosis for water uptake by maize roots, the hydraulic properties of roots in the F1 hybrid (Hudan 4) were compared with those of its inbred parents (♂ 478 and ♀ Tian 4) at cellular, singl...To examine the potential heterosis for water uptake by maize roots, the hydraulic properties of roots in the F1 hybrid (Hudan 4) were compared with those of its inbred parents (♂ 478 and ♀ Tian 4) at cellular, single-root and whole-root system levels under well-watered and water-deficit conditions. The cell hydraulic conductivity (Lpc) decreased under water deficit, but the Lp c of the F1 was higher than that of its inbred parents with or without stress from water deficit. Marked reductions in Lp c were observed following Hg2+ treatment. The hydrostatic hydraulic conductivity of single roots (hydrostatic Lp sr ) varied among genotypes under the two water treatments, with the highest in the F1 and the lowest in ♂ 478. Radial hydraulic conductivity (radial Lpsr ) and axial hydraulic conductance (Lax ) of the three genotypes varied similarly as Lpsr . The variations in hydraulic parameters were related to root anatomy. Radial Lp sr was negatively correlated with the ratio of cortex width to root diameter (R2=-0.77, P<0.01), whereas L ax was positively correlated with the diameter of the central xylem vessel (R2 =0.75, P<0.01) and the cross-sectional area of xylem vessels (R2 =0.93, P<0.01). Hydraulic conductivity (Lpwr ) and conductance (Lwr ) of the whole-root system followed the same trend under the two water treatments, with the highest values in the F1 . The results demonstrated that heterosis for water uptake by roots of the F1 occurred at cellular, single-root and whole-root system levels under well-watered and water-deficit conditions.展开更多
A green house experiment was conducted at Dejen, Northwest Ethiopia, with the objective of quantifying the critical soil water deficit and P levels that affect yield and yield components of soybean, and determine the ...A green house experiment was conducted at Dejen, Northwest Ethiopia, with the objective of quantifying the critical soil water deficit and P levels that affect yield and yield components of soybean, and determine the critical soil water deficit levels influencing P uptake in soybean. The treatment consisted of factorial combination of four available soil water (ASW) deficit levels (0%, 25%, 50% and 75%) and four levels of phosphorus (0, 10, 20, and 30 kg·ha-1) laid out in RCBD with four replications using soy bean variety Jalale as a planting material. The experiment was conducted under green house condition at Dejen, South Ethiopia during the 2011 academic year. Air dried soil was filled in the pots and seeds were sown on May 13, 2011. Four plants were maintained on each pot after thinning till flowering but after flowering, the total number of plants per pot was reduced to three as one plant which was used for measurement of root biomass. The water deficit treatments were imposed after the plants have been fully established 2 weeks after emergence just before branching stage. The water deficiency was imposed through maintaining the soil moisture content below field capacity at the deficit levels of 25%, 50% and 75%. The 75% of ASW deficit resulted in the longest days (45) to flowering and maturity (99) compared to the 0%, 25% and 50% deficit levels. Also, the 75% of ASW deficit level resulted in shorter plants (55 cm), the lowest leaf area (82.6 cm2), the highest root to shoot ratio (0.0168) and the lowest DM accumulation (161.3 gm-2) compared to the other ASW deficit levels. Likewise, the 75% of ASW deficit level gave the lowest number of pods per plant (4.13), seeds per pod (1.69), 100 seed weight (2.54 g), seed yield (13.4 g·m-1), above ground biomass (174.6 g·plant-1) and harvest index (0.08) compared to the other ASW deficit treatments. The degree of sensitivity to drought increased dramatically (from 0.0423 at 25% to 0.9604 at 75%) with increase in water deficit level. Tissue analysis results indicated that the highest seed P concentration (1.285%) and uptake (432.5 g·plant-1) were obtained at the 0 ASW deficit and 30 kg·P·ha-1 and the lowest were obtained at 75% ASW deficit and all rate of applied P. On the contrary, the highest straw P concentration (1.88%) and uptake (552.7 g·plant-1) were recorded at 75% and 25% of ASW deficit levels and 30 kg·P·ha-1, respectively. However, the total P uptake was influenced only by ASW deficit levels in that the relatively minimum and maximum values were observed at 75% and 0% of ASW deficit levels, respectively. It can be concluded that the critical ASW deficit levels that affect yield and yield components of soybean and uptake of total P lie between 25% and 50% of available water deficit levels. The parameters started to decline significantly from the 50% of ASW deficit onwards. As it is a green house experiment, further study on more number of ASW deficit levels and soil types under different field conditions needs to be done to reach at a conclusive recommendation.展开更多
The water requirement pattern for tobacco(Yun 85) was identified based on analysis of data obtained from pot experiments in a canopy at the Xiuwen Irrigation Test Central Station in Guizhou Province, China. The result...The water requirement pattern for tobacco(Yun 85) was identified based on analysis of data obtained from pot experiments in a canopy at the Xiuwen Irrigation Test Central Station in Guizhou Province, China. The results showed that the tobacco water requirement and the tobacco water requirement intensity throughout the growth period in pot experiments were significantly lower than those in field production. In pot experiments, the tobacco water requirement throughout the growth period ranged from 159.00 to 278.90 mm, with a reduction in the range of241e441 mm, as compared with that in field production. Also, the average water requirement intensity at the vigorous growing stage was1.97 mm/d, and the water requirement and water requirement module were 33.80e72.60 mm and 16.39%e33.09%, respectively, at the group stage, almost equal to their values at the vigorous growing stage. The patterns of the tobacco water requirement and water requirement module in pot experiments were different from those in field production. In pot experiments, the tobacco water requirement and water requirement module ranked the highest at the mature stage, followed by those at the group/vigorous growing and rejuvenation stages, while the water requirement intensity ranked the highest at the vigorous growing stage, followed by those at the mature, group, and rejuvenation stages. The pattern of the water requirement intensity in pot experiments was consistent with that in field production. In addition, the response of the tobacco water requirement to water deficit was also analyzed. Serious water deficit at the vigorous growing stage and continuous water stress at the group,vigorous growing, and mature stages can greatly influence the tobacco water requirement. Water deficit led to reductions in the water requirement and water requirement intensity at each growth stage. The vigorous growing stage exhibited the highest sensitivity to water deficit.The lower limit of moderate soil water stress at the vigorous growing stage was 65% of the field capacity. Results of this study can help to establish a reasonable irrigation schedule for tobacco production in Guizhou Province, China.展开更多
Scarcity of rainfall and limited irrigation water resources is the main challenge for agricultural expanding policies and strategies. At the same time, there is a high concern to increase the area of wheat cultivation...Scarcity of rainfall and limited irrigation water resources is the main challenge for agricultural expanding policies and strategies. At the same time, there is a high concern to increase the area of wheat cultivation in order to meet the increasing local consumption. The big challenge is to incerese wheat production using same or less amount of irrigation water. In this trend, the study was carried out to analyze the sensitivity of wheat yield to water deficit using remotely sensed data in El-Salhia agricultural project which located in the eastern part of Nile delta. Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) were extracted from Landsat 7. Water Deficit Index (WDI) used both LST minus air temperature (Tair) and vegetation index to estimate the relative water status. Yield response factor (ky) was derived from relationship between relative yield decrease and relative evapotranspiration deficit. The relative Evapotranspiration deficit was replaced by WDI. Linear regression was found between predicted wheat yield and actual wheat yield with 0.2?6, 0.025, 0.252 and 0.76 as correlation coefficient on 30th of Dec. 2012, 15th of Jan. 2013, 16th of Feb. 2013 and 20th of Mar. 2013 respectively. The main objective of this study is using a combination between FAO 33 paper approach and remote sensing techniques to estimate wheat yield response to water.展开更多
A study was conducted at Akron, CO, USA, on a Weld silt loam in 2004 to quantify the effects of water deficit stress on corn (Zea mays, L.) root and shoot biomass. Corn plants were grown under a range of soil bulk den...A study was conducted at Akron, CO, USA, on a Weld silt loam in 2004 to quantify the effects of water deficit stress on corn (Zea mays, L.) root and shoot biomass. Corn plants were grown under a range of soil bulk density and water conditions caused by previous tillage, crop rotation, and irrigation management. Water deficit stress (Dstress) was quantified by the number of days when the water content in the surface 0.3 m deviated from the water content range determined by the Least Limiting Water Range (LLWR). Root and shoot samples were collected at the V6, V12, and R1 growth stages. There was no significant correlation between Dstress and shoot or root biomass at the V6 growth stage. At the V12 and R1 growth stages, there were negative, linear correlations among Dstress and both root biomass and shoot biomass. The proportional decrease of shoot biomass was greater than the proportional decrease in root biomass, leading to an increase in the root:shoot ratio as water deficit stress increased at all growth stages. Determining restrictive soil conditions using the LLWR may be useful for evaluating improvement or degradation of the soil physical environment caused by soil management.展开更多
Adopting a better tillage system not only improves the soil health and crop productivity but also improves the environment. A field experiment was conducted to investigate the effects of tillage and irrigation managem...Adopting a better tillage system not only improves the soil health and crop productivity but also improves the environment. A field experiment was conducted to investigate the effects of tillage and irrigation management on wheat (Triticum aestivum L.) production in a post-rice (Oryza sativa L.) management system on silty clay loam soil (acidic Alfisol) for 2003-2006. Four irrigation levels (RF: rainfed;I1: irrigation at crown root initiation (CRI);I2: irrigation at CRI + flowering;I3: irrigation at CRI + tillering + flowering), and two tillage systems (ZT: zero tillage and CT: conventional tillage) were tested. Zero tillage compared to CT, resulted in higher bulk density (1.34 vs 1.23 Mg –3), lower total porosity (48.7 vs 52.9%), higher penetration resistance (1.51 vs 1.37 MPa), lower saturated hydraulic conductivity (1.60 vs 92.0 mm h–1), lower infiltration rate (9.40 vs 36.6 mm h–1) and higher volumetric available water capacity (7.9 vs 7.5%) in the surface 0.15 m soil layer. Irrigation levels significantly affected crop water use, wheat yield, and water use efficiency (WUE). Average total water use was 461, 491, 534 and 580 mm under RF, I1, I2 and I3 treatments, respectively. Grain and straw yield of wheat were statistically the same under ZT and CT during 2003-2004;the values, averaged over four irrigation levels were 2.10 and 2.38 Mg a–1 for grain, and 3.46 and 3.67 Mg a–1 for straw, respectively. Grain yield declined by 22%, 11% and 8% of I3 (2.32 Mg ha–1) with RF, I1 and I2 treatments, respectively, under ZT;and by 13%, 8% and 5% of I3 (2.61 Mg ha–1) with RF, I1 and I2 treatments under CT. Average values of WUE were 4.33 kg ha–1 m–1 and 2.35 m3–1 grain for the ZT and CT treatments. Wheat yield increased with increased irrigation levels for all the cropping seasons. Results from this study concluded that ZT system was better compared to the CT system even with lower yields due to lower input costs for this treatment.展开更多
The effect of foliar applications of a kaolin clay particle film (Surround WP) on leaf temperature (Tlf), chlorophyll fluorescence (Fv/Fm), shoot length, production and water relations in well-irrigated and water-stre...The effect of foliar applications of a kaolin clay particle film (Surround WP) on leaf temperature (Tlf), chlorophyll fluorescence (Fv/Fm), shoot length, production and water relations in well-irrigated and water-stressed rose cut plants (Rose spp) were studied during ten weeks. Plants were sprayed twice at first and fifth week after the experiment started with aqueous suspensions of Kaolin (Surround) at a dose of 5% (w/v). The interaction between Kaolin applications and water status did not showed significances. Water stress decreased the stomatal conductance (gs), leaf water content (LWC), shoot length and the number of marketable floral stems. Kaolin sprays did not affect on SPAD readings, chlorophyll fluorescence, gs, LWC and shoot length. Kaolin reduced leaf temperature by 2.5°C approximately at midday compared to plants non-sprayed with kaolin. These results show that kaolin foliar applications could be considered an useful tool at early growth stage in improving rose plant acclimation to high temperatures levels under greenhouse conditions in tropical regions.展开更多
Accurate assessment of water deficit and related uncertainties in water-scarce areas is strategically important in various fields of water resources management. This study developed a hybrid approach integrating conce...Accurate assessment of water deficit and related uncertainties in water-scarce areas is strategically important in various fields of water resources management. This study developed a hybrid approach integrating conceptual water balance model and econometric regression to estimate water shortage and its related uncertainties in water-scarce areas. This hybrid approach was used to assess the agricultural water deficit of Beijing, an extremely water-scarce area in China. A predictive model of agricultural water demand was developed using the stepwise multiple regression method, and was validated by comparing the predicted values with observed data. Scenario analysis was employed to investigate the uncertainties of agricultural water shortage and agricultural water demand. This modeling approach can assist water administration in creating sustainable water allocation strategies in water-scarce areas.展开更多
Maize ovary development is linked to kernel formation. Soil water deficit results in ovary abortion because of low water potential (ψ_w) resulting in inhibition of photosynthesis from anthesis to silking stage. Thus,...Maize ovary development is linked to kernel formation. Soil water deficit results in ovary abortion because of low water potential (ψ_w) resulting in inhibition of photosynthesis from anthesis to silking stage. Thus,drought is a key factor causing yield losses in maize,especially near the time of pollination. Earlier studies have indicated that selenium (Se) maintains antioxidative defence systems and enhances sugar and starch accumulation. The effects of Se on maize ovary development were studied in drought stress conditions. Maize ovary development was studied through observations on starch,membrane integrity,fresh weight and dry weight in drought-treated or unstressed glasshouse-grown plants,and crop yield,yield structure,leaf,stem and ear biomass accumulation were also analyzed. Results indicated that Se increased the stress tolerance of the crop,even though ovary abortion was not eliminated by Se treatments under low w. Under well-watered control conditions,Se had also negative effects. When the first ear was not succesfully pollinated or the ovaries aborted,the plants developed more ears. Even though these later formed ears did not produce kernels,they significantly increased the dry weight of the plants under water deficit. It could be concluded that The optimal concentration for maize of Se applied through roots is about 0.01 mg kg-1 (supplied as Na2SeO4) soil or less.展开更多
[Objective] The study aimed to find a possible way to combat or alleviate the negative effects caused by high temperature and water deficit at the growth stage of peak boll-setting.[Method] With Bt transgenic cotton G...[Objective] The study aimed to find a possible way to combat or alleviate the negative effects caused by high temperature and water deficit at the growth stage of peak boll-setting.[Method] With Bt transgenic cotton GK22 as the test cultivar,a potted experiment was carried out to investigate the effects of the regulation of external substances(the water solutions of pix,urea and their mixture) on the physiological parameters,insecticidal protein content,yield and yield component of cotton plants in artificial climate chambers treated with high temperature and water deficit.[Result] The application of external pix,urea or their mixture was effective in stabilizing the physiological parameters of cotton plants,insecticidal protein content,yield and yield components.Compared with the exclusive application of pix and urea,the mixture of pix and urea played the most effective role in stabilizing the content of chlorophyll,soluble sugar and insecticidal protein,alleviating the increase of the content of free amino acids and proline,and increasing boll number per plant,boll weight and seed cotton yield.[Conclusion] The water solutions of pix,urea or their mixtures can be used to combat or alleviate the stress of high temperature and water deficit if they are sprayed onto cotton plants prior to stress occurrence.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.32172520)the earmarked fund for China Agriculture Research System(Grant No.CARS-26)。
文摘Pre-harvest water deficit(PHWD)plays an important role in sugar accumulation of citrus fruit.However,the mechanism is not known well.Here,it was confirmed that PHWD promoted sucrose accumulation of citrus fruit,but had limited effect on fructose,glucose and total acid.A sucrose transporter,Cs SUT1,which localizes to the plasma membrane,was demonstrated to function in sucrose transport induced by PHWD.Compared to wild-type,Cs SUT1 overexpression in citrus calli stimulated sucrose,fructose and glucose accumulation,while its silencing in juice sacs reduced sucrose accumulation.Increased sugar accumulation in transgenic lines enhanced plant drought tolerance,and resulted in decreased electrolyte leakage,malondialdehyde and hydrogen peroxide contents,as well as increased superoxide dismutase activity and proline contents.An abscisic acid(ABA)-responsive transcription factor,Cs ABF3,was found with a same expression pattern with Cs SUT1 under PHWD.Yeast one-hybrid,electrophoretic mobility shift assay and dual-luciferase assays all revealed that Cs ABF3 directly bound with the Cs SUT1 promoter by ABA responsive elements.When Cs ABF3 was overexpressed in citrus calli,the sucrose,fructose and glucose concentration increased correspondingly.Further,transgenic studies demonstrated that Cs ABF3 could affect sucrose accumulation by regulating Cs SUT1.Overall,this study revealed a regulation of Cs ABF3 promoting Cs SUT1 expression and sucrose accumulation in response to PHWD.Our results provide a detail insight into the quality formation of citrus fruit.
基金sponsored by the National Natural Science Foundation of China(31461143015,31271641,31471438)the National Key Technology Support Program of China(2014AA10A605,216YFD0300206-4)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),Chinathe Jiangsu Creation Program for Post-graduation Students,China(KYZZ15_0364)
文摘This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency(WUE) under alternate wetting and drying(AWD) irrigation than check rice. Two super rice cultivars and two elite check rice cultivars were grown in pots with three soil moisture levels, well watered(WW), moderate water deficit(MWD) and severe water deficit(SWD). Two cultivars, each for super rice and check rice, were grown in field with three irrigation regimes, alternate wetting and moderate drying(AWMD), alternate wetting and severe drying(AWSD) and conventional irrigation(CI). Compared with that under WW, grain yield was significantly decreased under MWD and SWD treatments, with less reduction for super rice than for check rice. Super rice had higher percentage of productive tillers, deeper root distribution, higher root oxidation activity, and greater aboveground biomass production at mid and late growth stages than check rice, especially under WMD and WSD. Compared with CI, AWMD increased, whereas AWSD decreased grain yield, with more increase or less decrease for super rice than for check rice. Both MWD and SWD treatments and either AWMD or AWSD regime significantly increased WUE compared with WW treatment or CI regime, with more increase for super rice than for check rice. The results suggest that super rice has a stronger ability to cope with soil water deficit and holds greater promising to increase both grain yield and WUE by adoption of moderate AWD irrigation.
基金This study was supported by the National Key Research and Development Program of China(2016YFD0300109 and 2018YFDO200703)the National Natural Science Foundation of China(31771709)+2 种基金the Jiangsu Agricultural lndustry Technology System of China(JATS[2019]458)the JiangsuAgriculture Science and Technology Innovation Fund,China(Cx[19]3056)and the Priority Academic Program Development of Jiangsu Higher Education Institutions,China.
文摘Waxy maize is widely cultivated under rainfed conditions and frequently suffers water shortage during the late growth stage.In this study,a pot trial was conducted to examine the effects of post-silking drought on leaf photosynthesis and senescence and its influence on grain yield.Two waxy maize hybrids,Suyunuo 5(SYN5)and Yunuo 7(YN7),were grown under the control and drought(soil moisture content was 70–80%and 50–60%,respectively)conditions after silking in 2016 and 2017.The decrease in yield was 11.1 and 15.4%for YN7 and SYN5,respectively,owing to the decreased grain weight and number.Post-silking dry matter accumulation was reduced by 27.2%in YN7 and 26.3%in SYN5.The contribution rate of pre-silking photoassimilates transferred to grain yield was increased by 15.6%in YN7 and 10.2%in SYN5,respectively.Post-silking drought increased the malondialdehyde content,but decreased the contents of water,soluble protein,chlorophyll,and carotenoid in the leaves.The weakened activities of enzymes involved in photosynthesis(ribulose-1,5-bisphosphate carboxylase and phosphoenolpyruvate carboxylase)and antioxidant system(catalase,superoxide dismutase and peroxidase)reduced the photosynthetic rate(Pn)and accelerated leaf senescence.The correlation results indicated that reduced Pn and catalase activity and increased malondialdehyde content under drought conditions induced the decrease of post-silking photoassimilates deposition,ultimately resulted in the grain yield loss.
基金financially supported by the National Natural Science Foundation of China(31771773 and 31971931)the National Key Research and Development Program of China(2016YFD0100502)。
文摘The content and composition of wheat storage proteins are the major determinants of dough rheological properties and breadmaking quality and are influenced by cultivation conditions.This study aimed to investigate the effects of water deficit and high N-fertilizer application on wheat storage protein synthesis,gluten secondary structure,and breadmaking quality.Reverse-phase ultrahigh-performance liquid chromatography analysis showed that storage protein and gluten macropolymer accumulation was promoted under both independent applications and a combination of water-deficit and high N-fertilizer treatments.Fourier-transform infrared spectroscopy showed that water deficit and high N-fertilizer treatments generally improved protein secondary structure formation and lipid accumulation,and reduced flour moisture.In particular,high N-fertilizer application increasedβ-sheet content by 10.4%and the combination of water-deficit and high N-fertilizer treatments increased random coil content by 7.6%.These changes in gluten content and secondary structure led to improved dough rheological properties and breadmaking quality,including superior loaf internal structure,volume,and score.Our results demonstrate that moderately high N-fertilizer application under drought conditions can improve gluten accumulation,gluten secondary structure formation,and baking quality.
基金the National Key R&D Program of China,Grant No.2020YFD1000902Natural Science Foundation of Heilongjiang Province of China,Grant No.LH2021C023.
文摘Soybeans are one of the most important grain crops worldwide.Water deficit,which seriously affects the yield and quality of soybeans,is the main abiotic stress factor in soybean production.As a follow-up study,the droughttolerant soybean variant Heinong 44 was analyzed via proteome analysis.Soybean was exposed to water deficit for 0,8,and 24 h,and protein samples were extracted for detection of differentially expressed proteins.Protein sequencing of leaf tissues under water stress yielded a total of 549 differentially expressed proteins:75 and 320 upregulated proteins as well as 70 and 84 downregulated proteins were obtained after 8 and 24 h of water deficit,respectively.Gene Ontology analysis revealed that most of the differentially expressed proteins(DEPs)were involved in catalytic activity,molecular function,and metabolic processes,whereas some of them were involved in photosynthesis,carbon metabolism,and energy metabolism.We also identified some differentially expressed proteins that may be involved in the regulation of water deficit response.Our study provides a theoretical basis for the breeding of drought-resistant soybean varieties.
基金supported by the National Natural Science Fundation of China(30170640)Natural Science Fund of Liaoning Provice,China(20022080).
文摘Four irrigation treatments were designed with 2, 4, 6 and 8 d intervals to irrigate, respectively. Watering was stopped when the reading of the moisture tension sensor reached zero. The results indicated that glucose and fructose content of tomato's fruit were increased but sucrose content was decreased with fruit growth and development. In different stages, carbohydrate content of tomato fruit in the treatment 3 was the highest, in the treatment 2 was higher, and in the other treatments was the lowest. SS(sucrose synthase) activity was decreased but SPS(sucrose phosphate synthase) activity was increased with development of tomato. SS and SPS activity were increased but acid invertase and neutral invertase activity of ripe stage were decreased under deficit irrigation. Glucose and fructose content were increased in leaves of tomato under water deficit.Soluble sugars, organic acid and the ratio of sugar/acid in tomato fruits were increased and dry matter accumulation of plant was enhanced under water deficit. But the growth of fruits upside the plant and its dry matter accumulation were badly affected under water stress.
基金supported by the National Research Foundation of Korea (NRF) Grant (NRF-2011-616-F00013)supported by post-doctoral grantsupported by the scholarship from BK21Plus program, Ministry of Education, Republic of Korea
文摘To evaluate the response of alfalfa to water deficit(WD) stress, WD-induced candidates were investigated through a proteomic approach. Alfalfa seedlings were exposed to WD stress for 12 and 15 days respectively, followed by 3 days re-watering. Water deficit increased H2O2 content, lipid peroxidation, DPPH(1,1-diphenyl-2-picrylhydrazyl)-radical scavenging activity, and the free proline level in alfalfa roots. Root proteins were extracted and separated by two-dimentional polyacrylamide gel electrophoresis(2-DE). A total of 49 WD-responsive proteins were identified in alfalfa roots; 25 proteins were reproducibly found to be up-regulated and 24 were down-regulated. Two proteins, namely cytosolic ascorbate peroxidase(APx2) and putative F-box protein were newly detected on 2-DE maps of WD-treated plants. We identified several proteins including agamous-like 65, albumin b-32, inward rectifying potassium channel, and auxin-independent growth promoter. The identified proteins are involved in a variety of cellular functions including calcium signaling, abacisic acid(ABA) biosynthesis, reactive oxygen species(ROS) regulation, transcription/ translation, antioxidant/detoxification/stress defense, energy metabolism, signal transduction, and storage. These results indicate the potential candidates were responsible for adaptive response in alfalfa roots.
基金the National Natural Science Foundation of China(31271661,30871477)the National Basic Research Program of China(2009CB118602)+1 种基金the Special Fund for Agro-Scientific Research in the Public Interest of China(201203100)the Key Technologies R&D Program of China during the 12th Five-Year Plan period(2012BAD04B05)
文摘Two wheat cultivars(Triticum aestivum L.) were used to evaluate the effects of post-anthesis severe water deficit(SD) on starch content and granule size distribution and their relations with ethylene and spermidine(Spd). Comparison to the well-watered(WW) treatment, SD led to lower Spd and higher 1-aminocylopropane-1-carboxylic acid(ACC) concentrations and ethylene evolution rate(EER) in grains at the critical stage of forming starch granules. Application of Spd or aminoethoxyvinylglycine(AVG) significantly reduced ACC concentration and EER and increased Spd concentration, while ethephon or methylglyoxal-bis(MGBG) had an opposite impact. The volume and surface area distribution of starch granules showed a bimodal curve, while the number distribution exhibited a unimodal curve. SD caused a marked drop in grain weight, grain number and starch content, also led to a significant reduction in the proportion(both by volume and by surface area) of B-type starch granules(<10 μm), with an increase in those of A-type starch granules(>10 μm). Application of Spd or AVG increased the proportion(both by volume and by surface area) of B- type starch granules under SD. Correlation analysis suggested that ethylene and Spd showed an antagonism relation in the f ormation of B-type granules. These results suggested that it would be good for the formation of B-type starch granules to have the physiological traits of higher Spd and lower ACC concentrations and ethylene emission under SD.
基金supported by the CAS Action-plan for Western Development(KZCX2-XB3-13-03)Chinese National Natural Scientific Foundation(4120108431170385)
文摘The sustainability of ecosystem restoration of refuse dumps in open-pit coal mines depends on plant species selection,their configuration,and the optimal usage of water resources.This study is based on field experiments in the northern refuse dump of the Heidaigou open-pit coal mine in Inner Mongolia of China established in 1995.Eight plant configurations,including trees,shrubs,grasses,and their combinations,as well as the adjacent community of natural vegetation,were selected.The succession of the revegetated plants,soil water storage,the spatiotemporal distribution of plant water deficits degree and its compensation degree were also studied.Results indicated that the vegetation cover(shrubs and herbaceous cover),richness,abundance,soil nutrients(soil organic matter,N and P),and biological soil crust coverage on the soil surface are significantly influenced by the vegetation configurations.The average soil water storage values in the shrub + grass and grass communities throughout the growing season are 208.69 mm and 206.55 mm,which are the closest to that of in the natural vegetation community(215.87 mm).Plant water deficits degree in the grass and shrub + grass communities were the lowest,but the degrees of water deficit compensation in these configuration were larger than those of the other vegetation configurations.Differences in plant water deficit degree and water compensation among the different configurations were significant(P <0.05).Plant water deficit degrees were predominantly minimal on the surface,increased with increasing soil depth,and remained stable at 80 cm soil depth.The soil moisture compensation in the natural vegetation,shrub + grass,and grass communities changed at 10%,while that in other vegetation communities changed between 20% and 40%.Overall,we conclude that the shrub + grass and grass configuration modes are the optimal vegetation restoration models in terms of ecohydrology for future ecological engineering projects.
基金supported by the National Basic Research Program of China (2009CB118604)the National Natural Science Foundation of China (30971714)the Project 111 of the Ministry of Education of China (B12007)
文摘To examine the potential heterosis for water uptake by maize roots, the hydraulic properties of roots in the F1 hybrid (Hudan 4) were compared with those of its inbred parents (♂ 478 and ♀ Tian 4) at cellular, single-root and whole-root system levels under well-watered and water-deficit conditions. The cell hydraulic conductivity (Lpc) decreased under water deficit, but the Lp c of the F1 was higher than that of its inbred parents with or without stress from water deficit. Marked reductions in Lp c were observed following Hg2+ treatment. The hydrostatic hydraulic conductivity of single roots (hydrostatic Lp sr ) varied among genotypes under the two water treatments, with the highest in the F1 and the lowest in ♂ 478. Radial hydraulic conductivity (radial Lpsr ) and axial hydraulic conductance (Lax ) of the three genotypes varied similarly as Lpsr . The variations in hydraulic parameters were related to root anatomy. Radial Lp sr was negatively correlated with the ratio of cortex width to root diameter (R2=-0.77, P<0.01), whereas L ax was positively correlated with the diameter of the central xylem vessel (R2 =0.75, P<0.01) and the cross-sectional area of xylem vessels (R2 =0.93, P<0.01). Hydraulic conductivity (Lpwr ) and conductance (Lwr ) of the whole-root system followed the same trend under the two water treatments, with the highest values in the F1 . The results demonstrated that heterosis for water uptake by roots of the F1 occurred at cellular, single-root and whole-root system levels under well-watered and water-deficit conditions.
文摘A green house experiment was conducted at Dejen, Northwest Ethiopia, with the objective of quantifying the critical soil water deficit and P levels that affect yield and yield components of soybean, and determine the critical soil water deficit levels influencing P uptake in soybean. The treatment consisted of factorial combination of four available soil water (ASW) deficit levels (0%, 25%, 50% and 75%) and four levels of phosphorus (0, 10, 20, and 30 kg·ha-1) laid out in RCBD with four replications using soy bean variety Jalale as a planting material. The experiment was conducted under green house condition at Dejen, South Ethiopia during the 2011 academic year. Air dried soil was filled in the pots and seeds were sown on May 13, 2011. Four plants were maintained on each pot after thinning till flowering but after flowering, the total number of plants per pot was reduced to three as one plant which was used for measurement of root biomass. The water deficit treatments were imposed after the plants have been fully established 2 weeks after emergence just before branching stage. The water deficiency was imposed through maintaining the soil moisture content below field capacity at the deficit levels of 25%, 50% and 75%. The 75% of ASW deficit resulted in the longest days (45) to flowering and maturity (99) compared to the 0%, 25% and 50% deficit levels. Also, the 75% of ASW deficit level resulted in shorter plants (55 cm), the lowest leaf area (82.6 cm2), the highest root to shoot ratio (0.0168) and the lowest DM accumulation (161.3 gm-2) compared to the other ASW deficit levels. Likewise, the 75% of ASW deficit level gave the lowest number of pods per plant (4.13), seeds per pod (1.69), 100 seed weight (2.54 g), seed yield (13.4 g·m-1), above ground biomass (174.6 g·plant-1) and harvest index (0.08) compared to the other ASW deficit treatments. The degree of sensitivity to drought increased dramatically (from 0.0423 at 25% to 0.9604 at 75%) with increase in water deficit level. Tissue analysis results indicated that the highest seed P concentration (1.285%) and uptake (432.5 g·plant-1) were obtained at the 0 ASW deficit and 30 kg·P·ha-1 and the lowest were obtained at 75% ASW deficit and all rate of applied P. On the contrary, the highest straw P concentration (1.88%) and uptake (552.7 g·plant-1) were recorded at 75% and 25% of ASW deficit levels and 30 kg·P·ha-1, respectively. However, the total P uptake was influenced only by ASW deficit levels in that the relatively minimum and maximum values were observed at 75% and 0% of ASW deficit levels, respectively. It can be concluded that the critical ASW deficit levels that affect yield and yield components of soybean and uptake of total P lie between 25% and 50% of available water deficit levels. The parameters started to decline significantly from the 50% of ASW deficit onwards. As it is a green house experiment, further study on more number of ASW deficit levels and soil types under different field conditions needs to be done to reach at a conclusive recommendation.
基金supported by the Non-Profit Industry Financial Program of the Ministry of Water Resources of China(Grant No.201201025)the National Natural Science Foundation of China(Grants No.51179049 and50839002)
文摘The water requirement pattern for tobacco(Yun 85) was identified based on analysis of data obtained from pot experiments in a canopy at the Xiuwen Irrigation Test Central Station in Guizhou Province, China. The results showed that the tobacco water requirement and the tobacco water requirement intensity throughout the growth period in pot experiments were significantly lower than those in field production. In pot experiments, the tobacco water requirement throughout the growth period ranged from 159.00 to 278.90 mm, with a reduction in the range of241e441 mm, as compared with that in field production. Also, the average water requirement intensity at the vigorous growing stage was1.97 mm/d, and the water requirement and water requirement module were 33.80e72.60 mm and 16.39%e33.09%, respectively, at the group stage, almost equal to their values at the vigorous growing stage. The patterns of the tobacco water requirement and water requirement module in pot experiments were different from those in field production. In pot experiments, the tobacco water requirement and water requirement module ranked the highest at the mature stage, followed by those at the group/vigorous growing and rejuvenation stages, while the water requirement intensity ranked the highest at the vigorous growing stage, followed by those at the mature, group, and rejuvenation stages. The pattern of the water requirement intensity in pot experiments was consistent with that in field production. In addition, the response of the tobacco water requirement to water deficit was also analyzed. Serious water deficit at the vigorous growing stage and continuous water stress at the group,vigorous growing, and mature stages can greatly influence the tobacco water requirement. Water deficit led to reductions in the water requirement and water requirement intensity at each growth stage. The vigorous growing stage exhibited the highest sensitivity to water deficit.The lower limit of moderate soil water stress at the vigorous growing stage was 65% of the field capacity. Results of this study can help to establish a reasonable irrigation schedule for tobacco production in Guizhou Province, China.
文摘Scarcity of rainfall and limited irrigation water resources is the main challenge for agricultural expanding policies and strategies. At the same time, there is a high concern to increase the area of wheat cultivation in order to meet the increasing local consumption. The big challenge is to incerese wheat production using same or less amount of irrigation water. In this trend, the study was carried out to analyze the sensitivity of wheat yield to water deficit using remotely sensed data in El-Salhia agricultural project which located in the eastern part of Nile delta. Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) were extracted from Landsat 7. Water Deficit Index (WDI) used both LST minus air temperature (Tair) and vegetation index to estimate the relative water status. Yield response factor (ky) was derived from relationship between relative yield decrease and relative evapotranspiration deficit. The relative Evapotranspiration deficit was replaced by WDI. Linear regression was found between predicted wheat yield and actual wheat yield with 0.2?6, 0.025, 0.252 and 0.76 as correlation coefficient on 30th of Dec. 2012, 15th of Jan. 2013, 16th of Feb. 2013 and 20th of Mar. 2013 respectively. The main objective of this study is using a combination between FAO 33 paper approach and remote sensing techniques to estimate wheat yield response to water.
文摘A study was conducted at Akron, CO, USA, on a Weld silt loam in 2004 to quantify the effects of water deficit stress on corn (Zea mays, L.) root and shoot biomass. Corn plants were grown under a range of soil bulk density and water conditions caused by previous tillage, crop rotation, and irrigation management. Water deficit stress (Dstress) was quantified by the number of days when the water content in the surface 0.3 m deviated from the water content range determined by the Least Limiting Water Range (LLWR). Root and shoot samples were collected at the V6, V12, and R1 growth stages. There was no significant correlation between Dstress and shoot or root biomass at the V6 growth stage. At the V12 and R1 growth stages, there were negative, linear correlations among Dstress and both root biomass and shoot biomass. The proportional decrease of shoot biomass was greater than the proportional decrease in root biomass, leading to an increase in the root:shoot ratio as water deficit stress increased at all growth stages. Determining restrictive soil conditions using the LLWR may be useful for evaluating improvement or degradation of the soil physical environment caused by soil management.
文摘Adopting a better tillage system not only improves the soil health and crop productivity but also improves the environment. A field experiment was conducted to investigate the effects of tillage and irrigation management on wheat (Triticum aestivum L.) production in a post-rice (Oryza sativa L.) management system on silty clay loam soil (acidic Alfisol) for 2003-2006. Four irrigation levels (RF: rainfed;I1: irrigation at crown root initiation (CRI);I2: irrigation at CRI + flowering;I3: irrigation at CRI + tillering + flowering), and two tillage systems (ZT: zero tillage and CT: conventional tillage) were tested. Zero tillage compared to CT, resulted in higher bulk density (1.34 vs 1.23 Mg –3), lower total porosity (48.7 vs 52.9%), higher penetration resistance (1.51 vs 1.37 MPa), lower saturated hydraulic conductivity (1.60 vs 92.0 mm h–1), lower infiltration rate (9.40 vs 36.6 mm h–1) and higher volumetric available water capacity (7.9 vs 7.5%) in the surface 0.15 m soil layer. Irrigation levels significantly affected crop water use, wheat yield, and water use efficiency (WUE). Average total water use was 461, 491, 534 and 580 mm under RF, I1, I2 and I3 treatments, respectively. Grain and straw yield of wheat were statistically the same under ZT and CT during 2003-2004;the values, averaged over four irrigation levels were 2.10 and 2.38 Mg a–1 for grain, and 3.46 and 3.67 Mg a–1 for straw, respectively. Grain yield declined by 22%, 11% and 8% of I3 (2.32 Mg ha–1) with RF, I1 and I2 treatments, respectively, under ZT;and by 13%, 8% and 5% of I3 (2.61 Mg ha–1) with RF, I1 and I2 treatments under CT. Average values of WUE were 4.33 kg ha–1 m–1 and 2.35 m3–1 grain for the ZT and CT treatments. Wheat yield increased with increased irrigation levels for all the cropping seasons. Results from this study concluded that ZT system was better compared to the CT system even with lower yields due to lower input costs for this treatment.
文摘The effect of foliar applications of a kaolin clay particle film (Surround WP) on leaf temperature (Tlf), chlorophyll fluorescence (Fv/Fm), shoot length, production and water relations in well-irrigated and water-stressed rose cut plants (Rose spp) were studied during ten weeks. Plants were sprayed twice at first and fifth week after the experiment started with aqueous suspensions of Kaolin (Surround) at a dose of 5% (w/v). The interaction between Kaolin applications and water status did not showed significances. Water stress decreased the stomatal conductance (gs), leaf water content (LWC), shoot length and the number of marketable floral stems. Kaolin sprays did not affect on SPAD readings, chlorophyll fluorescence, gs, LWC and shoot length. Kaolin reduced leaf temperature by 2.5°C approximately at midday compared to plants non-sprayed with kaolin. These results show that kaolin foliar applications could be considered an useful tool at early growth stage in improving rose plant acclimation to high temperatures levels under greenhouse conditions in tropical regions.
基金supported by the Sino-Swiss Science and Technology Cooperation Program of Switzerlandthe Ministry of Science and Technology of China(Grant No.2009DFA22980)
文摘Accurate assessment of water deficit and related uncertainties in water-scarce areas is strategically important in various fields of water resources management. This study developed a hybrid approach integrating conceptual water balance model and econometric regression to estimate water shortage and its related uncertainties in water-scarce areas. This hybrid approach was used to assess the agricultural water deficit of Beijing, an extremely water-scarce area in China. A predictive model of agricultural water demand was developed using the stepwise multiple regression method, and was validated by comparing the predicted values with observed data. Scenario analysis was employed to investigate the uncertainties of agricultural water shortage and agricultural water demand. This modeling approach can assist water administration in creating sustainable water allocation strategies in water-scarce areas.
基金funded by the Finnish Education Funding,the Ningxia Science and Technology Key Projects (20030060)funded by Chinese Scholarship Council,China
文摘Maize ovary development is linked to kernel formation. Soil water deficit results in ovary abortion because of low water potential (ψ_w) resulting in inhibition of photosynthesis from anthesis to silking stage. Thus,drought is a key factor causing yield losses in maize,especially near the time of pollination. Earlier studies have indicated that selenium (Se) maintains antioxidative defence systems and enhances sugar and starch accumulation. The effects of Se on maize ovary development were studied in drought stress conditions. Maize ovary development was studied through observations on starch,membrane integrity,fresh weight and dry weight in drought-treated or unstressed glasshouse-grown plants,and crop yield,yield structure,leaf,stem and ear biomass accumulation were also analyzed. Results indicated that Se increased the stress tolerance of the crop,even though ovary abortion was not eliminated by Se treatments under low w. Under well-watered control conditions,Se had also negative effects. When the first ear was not succesfully pollinated or the ovaries aborted,the plants developed more ears. Even though these later formed ears did not produce kernels,they significantly increased the dry weight of the plants under water deficit. It could be concluded that The optimal concentration for maize of Se applied through roots is about 0.01 mg kg-1 (supplied as Na2SeO4) soil or less.
基金Supported by the National Natural Science Foundation of China(3077127231171483)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions,Jiangsu Innovation Project for Agriculture Science and Technology [cx(11)2054 ]Jiangsu Agriculture Science and Technology Support Program(SBE2010307)
文摘[Objective] The study aimed to find a possible way to combat or alleviate the negative effects caused by high temperature and water deficit at the growth stage of peak boll-setting.[Method] With Bt transgenic cotton GK22 as the test cultivar,a potted experiment was carried out to investigate the effects of the regulation of external substances(the water solutions of pix,urea and their mixture) on the physiological parameters,insecticidal protein content,yield and yield component of cotton plants in artificial climate chambers treated with high temperature and water deficit.[Result] The application of external pix,urea or their mixture was effective in stabilizing the physiological parameters of cotton plants,insecticidal protein content,yield and yield components.Compared with the exclusive application of pix and urea,the mixture of pix and urea played the most effective role in stabilizing the content of chlorophyll,soluble sugar and insecticidal protein,alleviating the increase of the content of free amino acids and proline,and increasing boll number per plant,boll weight and seed cotton yield.[Conclusion] The water solutions of pix,urea or their mixtures can be used to combat or alleviate the stress of high temperature and water deficit if they are sprayed onto cotton plants prior to stress occurrence.
