Two wheat cultivars （Triticum aestivum L.） were used to evaluate the effects ofpost-anthesis severe water deficit （SD） on starch content and granule size distribution and their relations with ethylene and spermidi...Two wheat cultivars （Triticum aestivum L.） were used to evaluate the effects ofpost-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-l-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 Ixm）, with an increase in those of A-type starch granules （〉10 ~tm）. 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 formation 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
Relationships between plant water status and gas exchange parameters at increasing levels of water stress were determined in Algerie loquats which grown in 50 I pots. Changes in soil water content and stem water poten...Relationships between plant water status and gas exchange parameters at increasing levels of water stress were determined in Algerie loquats which grown in 50 I pots. Changes in soil water content and stem water potential and their effects on stomatal conductance （Gs ） and net photosynthesis （Pn） rate were followed in control plants and in plants without irrigation until the latter reached near permanent wilting point and some leaf abscission took place. Then, the irrigation was restarted and the comparison repeated. Soil water content and stem water potential gradually diminished in response to drought reaching the minimum values of 0.9 mm and -5.0 MPa, respectively, 9 days after watering suspension. Compromised plant water status had drastic effects on Gs values that dropped by 97％ in the last day of the drought period. Pn was diminished by 80％ at the end of the drought period. The increasing levels of water stress did not cause a steady increase in leaf temperature in non-irrigated plants. Non-irrigated plants wilted and lost some leaves due to the severity of the water stress. However, all non-irrigated plants survived and reached similar Pn than control plants just a week after the irrigation was restarted, confirming drought tolerance of loquat and suggesting that photosynthesis machinery remained intact.展开更多
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 ofpost-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-l-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 Ixm）, with an increase in those of A-type starch granules （〉10 ~tm）. 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 formation 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partially financed by the Junta de Andalucía with European Union(FEDER)funds(AGR-03183)
文摘Relationships between plant water status and gas exchange parameters at increasing levels of water stress were determined in Algerie loquats which grown in 50 I pots. Changes in soil water content and stem water potential and their effects on stomatal conductance （Gs ） and net photosynthesis （Pn） rate were followed in control plants and in plants without irrigation until the latter reached near permanent wilting point and some leaf abscission took place. Then, the irrigation was restarted and the comparison repeated. Soil water content and stem water potential gradually diminished in response to drought reaching the minimum values of 0.9 mm and -5.0 MPa, respectively, 9 days after watering suspension. Compromised plant water status had drastic effects on Gs values that dropped by 97％ in the last day of the drought period. Pn was diminished by 80％ at the end of the drought period. The increasing levels of water stress did not cause a steady increase in leaf temperature in non-irrigated plants. Non-irrigated plants wilted and lost some leaves due to the severity of the water stress. However, all non-irrigated plants survived and reached similar Pn than control plants just a week after the irrigation was restarted, confirming drought tolerance of loquat and suggesting that photosynthesis machinery remained intact.
文摘在移动式防雨棚条件下．采用子母盆栽土培法和池栽微区试验相结合的方法，以冬小麦品种93中6为试验材料进行了调亏灌溉（Regulated deficit irrigation，RDI）试验研究，旨在了解调亏灌溉对小麦不同生育阶段生长动态、蒸腾速率（Tr）、光合速率（Pn）、光合产物积累与分配以及最终籽粒产量和水分利用效率（WUE）的影响，寻求适宜的调亏生育阶段（时期）和调节亏水度，为建立冬小麦RDI模式及其配套优化农艺方案提供理论依据。结果表明，适时适度的水分调亏显著抑制Tr，而Pn下降不明显；复水后Pn又具有超补偿效应，光合产物具有起补偿积累，且有利于向籽粒运转与分配;抑制营养生长，促进生殖生长。冬小麦调亏灌溉的适宜时段为三叶～返青，调亏度为40％FC（Field water capacity，FC）～60％FC，历时约55d；平均比对照增产0．88％～8．25％，节水12．80％～18755％，水分利用效率提高15．96％～32．98％。通过三因子正交旋转组合设计综合分析试验资料，分别建立了经济产量（Y）及水分利用效率（WUE）的数学模型。对模型的解析结果表明，当实施RDI时，可适当提高作物群体指标，并与施肥等其它农艺技术相结合，可以补偿RDI的负面效应。对所建数学模型进行目标联合仿真寻优，获得不同决策目标下RDI与农艺技术结合的优化方案。
