Drought influences cereal crop yield and ***,little is known about changes in the structural and functional properties of wheat starch under soil drought *** this study,two wheat cultivars were subjected to well-water...
Drought influences cereal crop yield and ***,little is known about changes in the structural and functional properties of wheat starch under soil drought *** this study,two wheat cultivars were subjected to well-watered(WW),moderate soil-drought(MD),and severe soil-drought(SD)from 7 tillers in the main stem to *** structural and functional properties of the resultant endosperm starch were *** comparison with WW soil,the MD increased starch accumulation in grains,the proportion of large starch granules,amylose and amylopectin long branch chain contents,and average amylopectin branch chain length,which was accompanied by the increase in activities of granule bound starch synthase and soluble starch synthase.
In order to understand the effects of water or N fertilizer on rice yield,quality and its physiological mechanism,a japonica hybrid rice cultivar Yongyou 2640 was grown in field,and two irrigation regimes,namely conti...
In order to understand the effects of water or N fertilizer on rice yield,quality and its physiological mechanism,a japonica hybrid rice cultivar Yongyou 2640 was grown in field,and two irrigation regimes,namely continuously flooded(CF)and alternate wetting and moderate drying irrigation(AWMD),and three N rates,namely LN(120 kg N/ha),MN(240 kg N/ha),HN(360 kg N/ha)were *** effect of irrigation regimes and N rates on rice growth and development,yield formation,nutrient uptake,and rice quality were *** results showed that,at the same N rate and compared with CF,AWMD significantly increased grain yield by 6.7%-1 8.6%because of increases in the percentage of filled grains and 1000-grain *** the CF regime,the grain yield at HN and MN were 21.1%-23%and 12%-15.5%higher than LN,*** yield at HN was lower than MN due to the lower percentage of filled grains and lower 1000-grain *** the AWMD regime,grain yield showed no significance between MN and HN although both MN and HN exhibited a higher grain yield than that LN,with the increase by 23.7%-25.3%and 23.2%-24.4%,respectively.
【研究背景】随着人们对水稻高产优质以及轻简化和机械化要求的不断提高,如何增强水稻的抗倒性已经成为越来越重要的问题。大气中二氧化碳（CO）和臭氧（O）浓度持续增加将显著改变作物的生长环境,进而对作物产量、品质及抗性产生深刻影响。相对产量和品质,人们对高CO/O浓度环境下水稻倒伏抗性的变化知之甚少。为了准确预测大气组份变化对未来粮食安全的影响,必需定量研究高浓度CO/O对作物倒伏抗性的影响及其作用机理。熏蒸环境接近于自然农田的试验平台为开展这一研究提供了重要契机。【材料与方法】利用自由空气中微量气体浓度增高（FACE,Free-Air gas Concentration Enrichment）系统结合自然光气体熏蒸平台,模拟本世纪中叶大气CO/O浓度,研究大气CO/O浓度升高对重要谷类作物水稻生长和抗倒性的影响及其相关生理原因,评估CO/O与主要栽培和环境因子的互作效应。【结果与分析】结果表明,大气CO浓度升高使稻米品质总体变劣,但使籽粒产量增加且倒伏风险减少。高CO浓度环境下水稻倒伏风险减少主要与基部节间抗折力明显增强有关,而后者又与节间充实程度增加有关,表现在单位节间干重、节间碳水化合物浓度以及茎鞘占全株干重的比例增加。臭氧胁迫使水稻籽粒产量、稻米品质和茎杆机械质量均呈下降趋势。臭氧胁迫导致水稻茎杆的抗折力显著下降,这与茎杆变细和充实程度减少有关,主要表现在节间横截面积、节间单位长度干重、茎鞘可溶性碳水化合物浓度以及光合产物向茎鞘和根系的转运比例减少。水稻结实期发生倒伏影响生长发育和抗倒性状对CO或O的响应,影响程度与供试品种和倒伏发生时期有关。高CO浓度环境生长的水稻发生倒伏后引起的产量和品质下降总体要小于对照,而臭氧胁迫水稻发生倒伏后则呈相反趋势,这种差异与相关生理过程的应答有关。大气CO或O浓度升高对水稻生长发育和抗倒性状的影响还与气象因子、熏蒸方式、供试品种和施氮量等因素有关。【结论】大气二氧化碳/臭氧浓度升高通过影响茎杆质量改变水稻的倒伏抗性,这种影响一定程度上受栽培措施和环境因子的调节。
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