干湿交替灌溉对水稻花后同化物转运和籽粒灌浆的影响. (Chinese)

Alternate wetting and drying irrigation (AWD) has been widely adopted in rice production for saving water and increasing water use efficiency. However, there is limited information about how AWD affects post-anthesis remobilization of assimilates and grain filling. To elucidate this issue, we planted three rice cultivars, including Yangliangyou 6 (indica hybrid), Wuyunjing 24 (japonicd) and Hanyou 8 (japonica) in the field. "With treatments of conventional irrigation (CI), alternate wetting and moderate soil drying irrigation (WMD) and alternate wetting and severe soil drying irrigation (WSD) from 10 days after transplanting to maturity. Grain yield and its components, grain filling of superior and inferior spikelets, changes in activities of the key enzymes involved in the conversion from sucrose to starch in grains, photosynthetic traits of flag leaf, the remobilization of non-structural carbohydrates in stems (culms and sheaths) and changes in starch hydrolytic enzymes in stems were investigated and isotope 1 3C was applied to trace redistribution of stem reserves. WMD significantly increased number of spikelets per panicle, 1000-grain weight, percentage of filled grains and grain yield of all the tested cultivars as compared with CI. Increases in 1000-grain weight and percentage of filled grains under WMD were mainly due to the enhancement of grain filling in inferior spikelets. Both WMD and WSD significantly enhanced the activities of α-amylase and β-amylase in stems and promoted translocation and redistribution of stem reserves, and increased the contribution of reserved carbohydrates in stems to grain yield. Moreover, WMD strengthened photosynthetic efficiency of flag leaf and enhanced the activities of the key enzymes involved in the conversion from sucrose to starch in inferior spikelets, whereas WSD exhibited the opposite effects. The results suggest that better leaf performance and higher activities of starch hydrolytic enzymes in stems, more remobilization of assimilates from stems to grains, and stronger activities of the key enzymes involved in sugar metabolism in inferior spikelets under the WMD are important physiological reasons for the enhancement of grain-filling in inferior spikelets of rice. [ABSTRACT FROM AUTHOR]

为阐明干湿交替灌溉对水稻花后同化物转运和籽粒灌浆的影响及其生理原因，大田种植扬两优6号、武运 粳24和旱优8号3个水稻品种，自移栽后10 d起，设置常规灌溉(CI)􀀀轻干-湿交替灌溉(WMD)和重干-湿交替灌溉 (W S D) 3种灌溉模式，观察产量及构成因素、强弱势粒灌浆动态、籽粒中酶活性变化、剑叶光合性能、茎銷非结构 性碳水化合物(NSC)运转及其淀粉水解酶活性变化，并利用13C同位素示踪茎鞘物质运转动态。结果表明，与CI相比， WMD显著增加了 3个水稻品种的每穗粒数、千粒重和结实率，进而提高籽粒产量。WMD显著提高千粒重和结实率 的主要原因是促进了弱势粒的灌浆。WMD和WSD显著增强了茎銷a-淀粉酶和p-淀粉酶活性，促进同化物质再运转 与分配，提高茎鞘储藏物质对粒重的贡献率。其中WMD提高了剑叶光合性能以及增强了水稻弱势粒中蔗糖-淀粉代 谢途径关键酶活性，WSD的作用相反。表明较好的叶片性能、花后茎中较多的同化物向籽粒转运、较高的茎銷淀粉 水解酶活性以及弱势粒中较高的糖代谢酶活性是WMD促进弱势粒灌漿的重要生理原因. [ABSTRACT FROM AUTHOR]

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