花后渍水高温交互效应对冬小麦旗叶光合特性及产量的影响

渍水和高温是长江中下游麦区冬小麦(Triticum aestivum L.)生育中后期的主要气象灾害因子。2009—2011年连续2个生长季盆栽烟农19，在籽粒形成期(花后5~8 d)和乳熟期(花后15~18 d)分别设渍水(土表水层1 cm)、高温昼(35±2)℃/夜(25±2)℃]和渍水+高温处理，探讨了渍水和高温双重胁迫对小麦开花后光合特性及产量的影响。结果表明，花后渍水、高温、渍水+高温逆境均显著降低旗叶净光合速率(P_n)、叶绿素含量(SPAD值)和气孔导度(G_s)和蒸腾速率(T_r)，增加胞间CO₂浓度(C_i)；同时降低穗粒数、千粒重及产量，但对成穗数影响不显著。渍水和高温胁迫对旗叶光合作用的主要限制因素是非气孔因素。从产量平均相对受害率看，其影响为渍水+高温逆境(37.7%)>渍水逆境(21.1%)>高温逆境(17.6%)，而胁迫时期的影响为籽粒形成期(30.8%)>乳熟期(20.1%)。渍水和高温的交互效应显著，且籽粒形成期逆境不良效应显著大于乳熟期。

Effect of Interaction of Waterlogging and High Temperature after Anthesis on Photosynthetic Characteristics of Flag Leaf and Yield in Winter Wheat

Waterlogging and high temperature are main stress factors during late growing period of winter wheat(Triticum aestivum L.) in Yangtze Valley region of China.To understand the effect of interaction of waterlogging and high temperature on photosynthetic characteristics and grain yield of wheat,we carried out a pot experiment,using the variety of Yannong 19,in continuous growing seasons from 2009 to 2011.At grain-forming(5-8 d after anthesis) and milking(15-18 d after anthesis) stages,waterlogging(1 cm of surface water layer),high temperature(35±2℃ of daytime/25±2℃ of nighttime),and waterlogging + high temperature stresses were imposed to wheat plants,separately.Waterlogging,high temperature,and both stresses showed significantly effects on photosynthetic characteristics of flag leaf and yield reducing photosynthetic rate(Pn),chlorophyll content(SPAD reading),stomatal conductance(Gs),and transpiration rate(Tr);enhancing intercellular CO2 concentration(Ci);and declining grain number per spike,1000-grain weight,and grain yield.However,in the case,spike number per pot was not affected significantly.Thus,the effects of waterlogging and high temperature on Pn did not result from stomata factor of flag leaf.The average relative injury rates(RIR) of yield were 37.7% for waterlogging + high temperature treatment,21.1% for waterlogging treatment,and 17.6% for high temperature treatment.Stress showed higher RIR at grain forming stage(30.8%) than at milking stage(20.1%).There was significant interaction between waterlogging and high temperature,and grain-forming stage was more sensitive to the interaction than milking stage.