花后高温胁迫下外施多胺对不同耐热性小麦产量性状及旗叶生理的影响

Effects of Polyamines on Yield Traits and Flag Leaf Physiology of Wheat under High Temperature Stress after Anthesis

为探究多胺对高温胁迫下小麦产量性状及旗叶生理的缓解效应,以耐热品种新春6号和热敏感品种新春31号为材料,通过田间人工模拟高温条件,测定分析了花后高温胁迫下外源精胺(Spm)和亚精胺(Spd)喷施后小麦产量性状、净光合速率(P n)、叶绿素含量、叶绿素荧光参数、旗叶表面温度等指标的变化。结果表明,高温胁迫导致新春6号和新春31号的穗粒数分别降低18%和26%,穗粒重分别减少25%和32%,理论产量分别下降29%和37%,且与正常温度对照差异均达显著水平;高温胁迫下外源Spm和Spd喷施能提高小麦旗叶P n、叶绿素含量、相对含水量(WC)以及灌浆后期的非光化学猝灭系数,显著降低旗叶激发能分配不平衡性和旗叶表面温度。综合来看,外源Spm缓解高温胁迫对小麦灌浆伤害的效果优于Spd,其调控作用与叶片P n、WC和气孔开闭密切相关。

In order to investigate the alleviating effects of polyamines on yield traits and flag leaf physiology of wheat under high temperature stress,with a heat resistant variety Xinchun 6 and a heat sensitive variety Xinchun 31 as materials,an experiment was conducted with artificial simulated high temperature in the field and exogenously applied spermine(Spm)and spermine(Spd).The wheat yield,net photosynthetic rate(P n),chlorophyll content,chlorophyll fluorescence parameters and surface temperature of the flag leaf were determined.The results showed that compared with the control under normal temperature,high temperature stress significantly decreased grain number per panicle of Xinchun 6 and Xinchun 31 by 18%and 26%,grain weight per panicle by 25%and 32%,and theoretical yield by 29%and 37%,respectively.Exogenous Spm and Spd increased the P n,chlorophyll content,water content(WC)and non-photochemical quenching coefficient(NPQ)in flag leaves at the later stage of grain filling under high temperature stress,and significantly reduced the imbalance of excitation energy distribution(β/α-1)and surface temperature of flag leaves.According to the alleviating effect of Spm and Spd on yield traits of two varieties under high temperature treatment and the dynamic changes of P n,WC and surface temperature of flag leaves in wheat during the filling stage,exogenous Spm had a better effect than Spd in alleviating the damage of heat stress,and its alleviating effect was closely related to P n,WC and stomatal opening and closing of leaves.