土壤干湿交替对小麦花前碳同化物分配的影响

Effects of distribution of fore-anthesis carbon assimilates of wheat under soil dry-wet alternation

采用盆栽小麦试验,在开花前7d利用14CO2光合标记,花后设置对照(A)、干湿交替5d循环(B)和10d循环(C)共3种水分处理。研究结果表明:约有19.0%～22.0%花前14C同化物被转运到籽粒。在B、C两种干湿交替处理中,籽粒对花前14C同化物动员量分别高出对照4.38%和3.02%,并且叶、鞘、茎等花前临时库中同化物输出比例相对高于正常供水的A处理。旗叶中可溶性糖和脯氨酸(Pro)含量对干湿反应敏感。灌浆后期,干湿交替处理的小麦旗叶中叶绿素(Chl)含量和光合速率与对照相比,相对减小,蒸腾速率和气孔导度也大大降低,并且二者变化趋势相一致。干湿交替供水,可部分补偿灌浆后期干旱导致光合不足、同化物减少的籽粒干物质的损失。

Using^(14) CO_2 labelled wheat of pot experiment at seven days pre-anthesis.The treatments in post-anthesis were control (A) and soil drying-wetting cycles of either 5(B) or 10 days (C).The result showed that about 19.0%~22.0% of^(14) C assimilates of pre-anthesis were transported to seeds.^(14) C assimilates of pre-anthesis were mobilized to seeds in B and C treatments was 4.38% and 3.02% higher than that of control,and output of assimilates of temporary pool in leaf and sheath and stem etc was higher than A treatment.Contents of soluble sugar and proline in flag leaf was sensitive with soil drying-wetting alternation.The rates of photosynthesis and contents of chlorophyll in flag leaf was lower than that of control during later filling stage,and transpiration rate and stomatal conductance was largerly droped,and the trends of change was the same.Supply water of drying-wetting alternation to wheat could partly compensated losses of dry matter of seeds induced by no-full photosynthesis and reduces of assimilate under water deficits during later filling stage.