摘要:针对长江中下游小麦开花期常遇连阴雨导致减产的现象，研究阴雨寡照对小麦籽粒淀粉合成和干物质积累的影响，旨在为该地区小麦抗逆稳产栽培提供理论依据。选用长江中下游小麦主栽品种‘扬麦18’（受渍迟钝型）和‘皖麦52’（受渍敏感型）为试验材料，在小麦开花后设置7 d、11 d和15 d的渍水遮阴处理，研究渍水遮阴对小麦籽粒发育过程中淀粉合成相关酶活性及淀粉、干物质积累的影响。结果表明，渍水遮阴处理后，小麦籽粒中腺苷二磷酸葡萄糖焦磷酸化酶（AGPase）、可溶性淀粉合成酶（SSS）和结合态淀粉合成酶（GBSS）活性在灌浆前期（花后10~15 d）与对照差异不显著，随着灌浆进程的推进，渍水遮阴处理与对照之间差异增大。灌浆中期（花后20 d）小麦籽粒中AGPase和SSS活性达到峰值时，渍水遮阴处理11 d、15 d的‘扬麦18’和‘皖麦52’籽粒中AGPase活性分别较对照下降1%、10%和11%、24%，SSS活性则下降5%、11%和9%、32%，且渍水遮阴处理11 d和15 d的小麦籽粒中SSS和GBSS活性在灌浆后期显著低于对照。用Logistic方程分别拟合籽粒淀粉和干物质的积累，花后渍水遮阴处理缩短了籽粒灌浆缓增期，降低了小麦籽粒灌浆的平均速率、淀粉积累的最大速率及平均速率，减少了籽粒淀粉和干物质的积累量。同时，渍水遮阴处理降低了小麦穗粒数和千粒重，使产量显著下降。随着渍水遮阴处理时间的延长，小麦籽粒中淀粉合成相关酶活性、干物质积累量及产量的下降幅度越大。迟钝型品种‘扬麦18’各指标的下降幅度均小于敏感型品种‘皖麦52’。小麦开花后渍水遮阴处理降低了籽粒中AGPase、SSS和GBSS活性，不利于籽粒淀粉合成及干物质的积累，导致产量下降显著。
关键词:小麦/
渍水/
遮阴/
淀粉合成酶活性/
灌浆特征/
淀粉积累特性/
干物质积累/
产量
Abstract:Focusing on the reduced wheat yield caused by continuous rain following anthesis in the middle and lower reaches of the Yangtze River, a pot experiment was designed to investigate the effects of shading and waterlogging on starch synthesis and dry matter accumulation in wheat grains, to provide information regarding adverse resistance cultivation and stable yield of wheat in the area. Two wheat varieties - 'Yangmai 18' (waterlogging-insensitive type) and 'Wanmai 52' (waterlogging-sensitive type) - that are domain varieties in the Yangtze River Basin of China were selected to investigate the effects of 7-, 11-, and 15-day shading and waterlogging treatments following anthesis on starch synthesis and dry matter accumulation in wheat grains. The results indicated that there were no significant differences between the control and shading and waterlogging treatments in terms of the activities of adenosine diphosphate-glucose pyrophosphate (AGPase), soluble starch synthase (SSS), and bound starch synthase (GBSS) in wheat grains during the earlier grain-filling stage (10-15 days after anthesis). However, with the development of the grain-filling process, the difference between the control and shading and waterlogging treatments increased. In the mid-grain-filling stage (20 days after anthesis), when the activities of the three key enzymes were highest. The 11-and 15-day shading and waterlogging treatments decreased the activity of AGPase in wheat grain by 1% and 10% for 'Yangmai 18', and by 11% and 24% for 'Wanmai 52', respectively. Further, the activity of SSS was decreased by 5% and 11% for 'Yangmai 18', and 9%, 32% for 'Wanmai 52', respectively, compared with the control. In addition, the activities of SSS and GBSS under 11-and 15-day shading and waterlogging treatments were significantly lower than those in the control during the late grain-filling stage. Simulating the process of starch accumulation and grain filling with a Logistic equation showed that compared with the control, the shading and waterlogging treatments shortened the duration of the slow increasing stage and decreased the average grain-filling rate, average and peak starch accumulation rates, and cumulative wheat starch and dry matter amounts. Simultaneously, the shading and waterlogging treatments decreased the grain number and 1000-kernel weight of wheat, thereby lowering the yield. The extented shading and waterlogging treatments duration induced a decline in the activities of SSS and GBSS as well as the starch and dry matter accumulation amount in wheat grains and yield. The waterlogging-insensitive variety 'Yangmai 18' showed slight decreases compared with the waterlogging-sensitive variety 'Wanmai 52' in each index. Shading and waterlogging stresses following anthesis of wheat decreased the activities of AGPase, SSS, and GBSS and affected the starch and dry matter accumulation in wheat grains, thereby leading to yield loss.
Key words:Wheat/
Waterlogging/
Shading/
Starch synthase activity/
Grain-filling characteristic/
Starch accumulation characteristic/
Dry matter accumulation/
Grain yield
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