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. |