油菜素内酯对春玉米灌浆期叶片光合功能与产量的调控效应

以玉米品种"郑单958"为材料,在大田条件下,采用植物生长调节物质油菜素内酯(brassinolide,BR)对苞叶和穗位叶喷施处理,研究了BR对玉米穗位叶功能、籽粒灌浆及产量的调控作用。结果表明,灌浆期随生育进程,玉米穗位叶叶绿素含量、光合速率、磷酸烯醇式丙酮酸羧化酶(PEPCase)、1,5-二磷酸核酮糖羧化酶(Ru BPCase)以及蔗糖磷酸合酶和蔗糖合酶的活性均显著下降。同时,籽粒蔗糖含量显著降低,但淀粉含量和粒重均显著增加。与对照相比,BR处理显著增加玉米穗位叶叶绿素含量,提高光合速率,增强PEPCase、Ru BPCase、蔗糖磷酸合酶和蔗糖合酶的活性。BR处理显著增加籽粒蔗糖和淀粉积累,提高玉米籽粒干物质积累。在产量构成上,BR显著缩短秃尖长度,增加穗粒数和千粒重,显著提高产量。本研究说明,灌浆期喷施BR可提高玉米叶源的活性,延长叶片光合功能持续期,促进籽粒灌浆和物质积累,从而实现增产。

Effect of Brassinolide on Leaf Photosynthetic Function and Yield in Spring Maize Filling Stage

A field experiment was conducted to investigate the effect of plant growth regulator brassinolide (BR) on the regulation of physiological activities of ear leaf, the grain filling and yield in spring maize (Zea mays L., cv. Zhengdan 958). Husks and ear leaves were treated with BR at 15 days after anthesis by foliar spraying. The results showed that the chlorophyll content, photosynthetic rate and activities of PEP carboxylaes, RuBP carboxylase, sucrose synthase and sucrose phosphate synthase in ear leaf as well as source content in kernel were significantly reduced, while starch accumulation and dry weight of kernel were increased during grain filling. BR significantly increased the content of chlorophyll and photosynthetic rate, enhanced the activities of PEP carboxylaes and RuBP carboxylase, definitely resulting in enhanced CO₂ assimilation. BR markedly increased the activities of sucrose synthase and sucrose phosphate synthase in ear leaf. And in kernel, the accumulation of sucrose and starch as well as the grain filling rate were accelerated by BR. BR treatment significantly reduced the length of ear barren tip, and increased the number of kernels per ear, which led to higher yield. These results suggest that BR treatment at filling stage may be a good strategy to get a high yield in maize, by enhancing activity of resource, delaying sencence and stimulating the ?ow of assimilate from the source to the sink.