Wx基因缺失对灌浆期小麦旗叶光合特性的影响

Effect of the Absence of Wx Genes on Flag Leaf Photosynthetic Characteristics of Wheat at the Filling Stage

小麦籽粒淀粉的合成不仅受到淀粉合成关键酶的影响,而且也受到光合作用的调控,Wx基因的缺失在很大程度上会影响小麦的淀粉合成,在一定程度上也可能对光合作用产生影响。本文以8个Wx小麦近等基因系为材料研究了Wx基因对小麦光合特性的影响,结果表明:3个Wx基因部分或全部缺失对小麦旗叶光合特性有较大影响,其中Wx-A1和Wx-B1基因的缺失可显著降低净光合速率,而全部Wx基因缺失则会使其增加。此外,Wx基因部分或全部缺失后,光合指标的相关性随之发生改变,胞间CO2浓度对光合作用不具有显著的抑制或促进作用,灌浆速率、干物质积累和水分利用效率的增加,以及气孔导度和蒸腾速率的降低。本研究对Wx基因对小麦光合特性乃至产量的影响以及丰富植物库源关系研究有重要意义。

Starch biosynthesis of wheat seeds was not only influenced by key enzymes but also regula- ted by photosynthesis, and the absence of Wx gene should affect the biosynthesis of wheat starch, may also had an impact on photosynthesis in a certain extent. Effect of Wx genes on flag photosynthetic characteristics was investigated by 8 Wx near-isogenic wheat lines in this study. The results showed that the genotype had no relation to photosynthesis, but the absence of part or all three Wx genes was influencing the flag photosynthetic characteristics greatly. The net photosynthetic rate decreased signifi- cantly in the absence of Wx-A1 and Wx-B1 genes, however, which was increased in the absence of three Wx genes. In the absence of part or all of three Wx genes, the relationship among photosynthetic indices changed and no inhabiting or stimulative action of intercellular CO2 concentration on photosyn- thesis was observed, filling rate and carbohydrate accumulating and water using efficiency increased,and the stomatal conductance and transpiration rate decreased. This study is of great importance for the effects of Wx gene on wheat photosynthetic characteristics, yield and researches of source-sink relation- ship