淹水胁迫对夏玉米籽粒灌浆特性和品质的影响

【目的】探讨气候变化下持续降雨造成的大田淹水对夏玉米籽粒灌浆特性和品质的可能影响。【方法】以登海605（DH605）和郑单958（ZD958）为试验材料，设置大田淹水时期（三叶期、拔节期、开花后10 d）和淹水持续时间（淹水3 d和6 d）处理，分析夏玉米籽粒干重和体积的增长、籽粒灌浆参数、籽粒粗脂肪、粗蛋白、总淀粉含量、支/直比值以及可溶性总糖和蔗糖含量等指标的变化。【结果】淹水胁迫后籽粒干重增长速率降低，籽粒灌浆参数减小，且三叶期淹水6 d下影响最大，DH605和ZD958到达最大灌浆速率时的天数（Tmax）、最大灌浆速率（Gmax）、灌浆速率最大时的生长量（Wmax）和籽粒灌浆活跃期（P）较对照分别下降 25.18%、18.44%、48.21%、36.45%和18.18%、1.69%、32.68%、31.80%；两品种淹水后均空秆率增加，穗粒数和千粒重显著降低，产量下降，减产幅度表现为三叶期淹水＞拔节期淹水＞开花后10 d淹水，淹水6 d＞淹水3 d；淹水下籽粒粗蛋白、总淀粉、可溶性总糖和蔗糖含量显著降低；支链淀粉含量显著降低，但直链淀粉含量有所升高，因而支/直比值降低；淹水后籽粒中粗脂肪含量显著提高，三叶期淹水6 d造成的影响最显著，两品种较对照分别提高了49.08%和33.08%。【结论】淹水胁迫显著降低了夏玉米籽粒最大灌浆速率及灌浆速率最大时的生长量，抑制了籽粒灌浆，严重影响籽粒干物质的积累，导致夏玉米产量显著下降；淹水胁迫降低了籽粒可溶性总糖、蔗糖和淀粉含量，淹水胁迫后籽粒粗蛋白含量和支/直比值也显著降低，而粗脂肪含量显著提高；三叶期淹水对其影响最显著，拔节期淹水次之，开花后10 d淹水的影响较小，其影响随淹水胁迫时间的延长而加剧。

Effect of Waterlogging on Grain Filling and Quality of Summer Maize

【Objective】This study is to investigate the effects of waterlogging on grain filling characteristics and quality of summer maize under field conditions.【Method】Two summer maize cultivars, Denghai605(DH605) and Zhengdan958(ZD958), were used as experimental materials. The field experiment was performed to explore the effects of waterlogging in different durations (3 and 6 days) on grain dry weight and volume, grain filling parameters, and grain quality of summer maize stalk at the three-leaf stage (V3), six-leaf stage (V6), and ten days after the tasseling stage (10VT).【Result】Results showed that the grain dry weight growth rate and grain filling parameters reduced significantly after waterlogging, and the decrease of two cultivars was the most in the treatment of waterlogging at V3 for 6 days. Days of maximum grain filling (Tmax), maximum grain filling (Gmax), weight of maximum grain filling rate (Wmax), and active grain filling period (P) of DH605 decreased by 25.18%, 18.44%, 48.21%, and 36.45%, while that of ZD958 decreased by 18.18%, 1.69%, 32.68% and 31.80%, respectively. Waterlogging increased barrenness, and decreased grain yield, kernel number per ear and 1000-grain weight, and the response to different waterlogging treatments showed: waterlogging at V3＞waterlogging at V6＞waterlogging at 10VT and waterlogging for 6 days＞waterlogging for 3 days. Waterlogging significantly decreased grain crude protein, total starch, grain total soluble sugar and sucrose content. The decrease of amylopectin and increase of amylase led to the decrease of their ratio; the decrease of grain crude fat content of two cultivars was the most in the treatment of waterlogging at V3 for 6 days, with 49.08% in DH605 and 33.08% in ZD958. 【Conclusion】 Waterlogging significantly reduced Gmax and Wmax, suppressed the grain-filling with decrease of accumulation grain dry matter, resulted in lower yields. Waterlogging decreased the grain soluble total sugar, sucrose and starch content. Grain protein content and the ratio of amylopectin and amylose significantly reduced after waterlogging, while the crude fat content increased significantly. It was most susceptible to be waterlogged at V3, followed by V6 and 10VT, and decreased with the increase of waterlogging duration.