干旱胁迫下小麦颖果内源激素的变化及其与胚乳发育的关系

为探明干旱胁迫下小麦颖果内源激素与胚乳发育的关系,以小麦品种扬麦16为材料,在幼苗返青至颖果成熟阶段进行干旱处理,采用树脂切片及显微摄影等技术观察小麦颖果和胚乳细胞发育的形态结构特征,并通过酶联免疫吸附法测定颖果生长素(IAA)、脱落酸(ABA)、赤霉素(GA_3、GA_4)、玉米素核苷(ZR)、二氢玉米素核苷(DHZR)的含量。结果显示,干旱胁迫缩短了小麦颖果发育进程,促进颖果早衰,导致颖果发育不良;显著降低了籽粒千粒重、可溶性糖含量和总淀粉含量,提高了蛋白质含量;促进颖果发育早期胚乳细胞分裂和淀粉积累,抑制了发育后期胚乳细胞的分裂、体积扩大和淀粉体充实,并提高了颖果整个发育过程中胚乳蛋白体的积累;提高了颖果发育前期IAA、GA_3、GA_4、ZR和DHZR的含量,ABA含量在整个发育时期均较高。说明干旱胁迫能通过影响颖果内源激素的积累来调控胚乳发育。

Relationship Between Changes of Endogenous Hormones and Development of Eendosperm in Wheat Caryopsis under Drought Stress

In order to investigate the relationship between endogenous hormones in wheat caryopsis and endosperm development under drought stress, Yangmai 16, which was treated with drought stress during plant regreening to caryopsis maturity stage, was used as material to observe the morphological and structural characteristics of wheat caryopsis and endosperm development by resin semi-thin slice and microscopy techniques in this study. At the same time, the contents of auxin(IAA), abscisic acid(ABA), gibberellin(GA₃, GA₄), zeatin riboside(ZR), and dihydrozeatin riboside(DHZR) in caryopsis were determined by enzyme-linked immunosorbent assay.From the aspect of caryopsis appearance, drought stress shortened the development of caryopsis and promoted premature aging of caryopsis, resulting in poor caryopsis development. Drought stress significantly decreased 1 000-grain weight, soluble sugar content and total starch content, but increased protein content of mature caryopsis. The endosperm cell division and starch accumulation was promoted under drought stress during the early stage of caryopsis development, but the further growth of endosperm, including endosperm cell division and expansion and starch filling, was inhibited at the late stage.Meanwhile,drought stress increased protein body accumulation in endosperm during the whole development of caryopsis.Furthemore,drought stress increased the contents of IAA, GA₃, GA₄, ZR and DHZR in caryopsis at the early development stage, but decreased their contents at the late stage. The accumulation of ABA content was increased under drought stress during the whole development period of caryopsis. The above results indicated that drought stress regulated endosperm development by affecting the accumulation of endogenous hormones in caryopsis.