花后高温胁迫下氮肥追施后移对小麦产量及旗叶生理特性的影响

为探明施用氮肥与减缓小麦花后高温伤害的关系并阐明其生理机制,于2011—2012年和2012—2013年连续两个生长季,选用小麦品种山农16和济麦22,在增温棚中进行花后11～15 d的高温胁迫处理,比较了氮肥全作基肥(T0)、1/2基肥+1/2拔节期追肥(T1)、1/2基肥+1/2孕穗期追肥(T2)3种施氮方案下的产量、产量构成因素、旗叶光合特性及部分酶的活性。在高温胁迫下,T2方案较T0和T1显著增加籽粒千粒重和产量,提高旗叶谷氨酰胺合成酶(GS)活性,增加旗叶气孔导度和光合速率,提高旗叶过氧化氢酶(CAT)和过氧化物酶(POD)活性,促进花前营养器官干物质向籽粒转运,增加开花后积累的干物质对籽粒的贡献率。两个品种结果基本一致。综合两年结果可以看出,T2处理显著优于T0和T1处理,T2处理能显著缓解高温胁迫的伤害,提高籽粒产量。

Effects of Postponed Application of Nitrogen Fertilizer on Yield and Physiological Characteristics of Flag Leaf in Wheat under Post-Anthesis Heat Stress

This study aimed to disclose the effect and physiological basis of postponed application of nitrogen fertilizer on alleviating the high-temperature damage after anthesis. In a two-year experiment from October 2011 to June 2013, winter wheat (Triticum aestivum L.) cultivars Shannong 16 and Jimai 22 were planted with three nitrogen treatments, namely T0 (total as basal fertilizer), T1 (a half of basal fertilizer and a half of nitrogen applied at jointing stage), and T2 (a half of basal fertilizer and a half applied at booting stage). High-temperature stress was simulated in plastic shed from 11 to 15 days after anthesis. Grain yield and its components, photosynthetic parameters of flag leaf, and activities of some important enzymes were compared among nitrogen treatments. The results indicated that T2 had higher 1000-grain weight and grain yield than T0 and T1 under heat stress. Besides, T2 had the effects on increasing glutamine synthetase (GS) activity, stomatal conductance, photosynthetic rate, and activities of hydrogen peroxidase (CAT) and peroxidase (POD) in flag leaf, stimulating translocation of pre-anthesis assimilate to grains, and increasing the contribution to grain of post-anthesis assimilate. Both cultivars had similar results. In an overall view, T2 is superior to T0 and T1 due to its significant effects on alleviating heat stress damage and increasing grain yield.