小麦生育后期施用水杨酸对千粒重的影响

目的]研究水杨酸(SA)在小麦上的增产效应与作用机理。方法]以大穗大粒型品种兰考矮早8为试材,在小麦灌浆期间,即花后5和18 d分别用1.5、1.0和0.5 mmol/L浓度的水杨酸对植株进行叶面喷施,在小麦成熟时测定其蛋白质、总淀粉、直链淀粉和支链淀粉含量。结果]各SA处理均使小麦千粒重有较多提高。花后5 d施用SA的效果高于花后18 d的施用效果,施用浓度均以1.5 mmol/L最佳。SA对直链淀粉的作用大于对蛋白质和支链淀粉的作用。SA提高千粒重的机理是增加了直链与支链淀粉的含量,对蛋白质含量影响不大。结论]小麦开花后喷施SA可延缓叶片衰老,有利于提高灌浆速率和光合产物的积累,从而提高了籽粒的充实度和千粒重。

Effect of Applying Salicylic Acid on 1000-seed Weight of Wheat in Late Growth Stage

Objective] The purpose was to study the yield-increasing effect and acting mechanism of salicylic acid(SA) on wheat.Method] With the variety Lankaoaizao 8 with big spike and big grain as tested material, during the filling stage of wheat,i.e.on the 5th and 18th day after flowering,the SA at 3 concn.of 1.5,1.0 and 0.5 mmol/L were sprayed on the leaves of plant resp.The contents of protein,total starch,amylose and amylopectin in wheat were determined when it matured.Result] All SA treatments enhanced the 1 000-seed weight of wheat more.The effect of applying SA on the 5th day after flowering was higher than that on the 18th day and their optimum applying concn.were 1.5 mmol/L.The effect of SA on amylose was bigger than that on protein and amylopectin.The mechanism of enhancing 1 000-seed weight by SA was increasing the contents of amylose and amylopectin,but SA had little influence on protein. Conclusion] Spraying SA on wheat after flowering could delay the senescence of leaf and was in favor of enhancing the filling velocity and the accumulation of photosynthate so as to enhance the grain plumpness and 1 000-seed weight.