赖草属牧草种子休眠与植物激素调控

Seed Dormancy and Hormone Control of Germination in Leymus Hochst

赖草属牧草种子存在不同程度的休眠。作者探讨了植物内源激素对种子休眠调控作用，结果表明，种子内萌发促进激素与抑制激素的比值对种子萌发起着重要的调节作用，当促进激素／抑制激素的比值较大时，种子解除休眠，提高萌发率。羊草与赖草种子不同部位的激素分析结果表明，萌发抑制部位主要是稃和胚乳，萌发抑制物主要是脱落酸（ABA）。萌发促进作用是多种激素（Z、ZR、IAA、GA3）的综合作用。该属牧草种子休眠属于由抑制物引起的生理性休眠。

Seeds in Leymus genus show a wide range of dormancy. This Paper deals with the endohormone control of dormancy in this genus. Experimental results showed that the ratio of promoting hormone to inhabitory hormone in the seeds played an important role in control of seed dormancy. Seed germination rate increased with and increase in the value of the promoting hormane to inhabitory hormone. It was further identified that ABA was the dominant inhabitory hormone in the seed and the main inhabitory sites were in the endosperm and the palea. Release of dormancy and germination promotion was caused by a comprehensive effect of various promoting hormones. Among the promoting substances, Zeatin(Z) and Zeatin riboside(ZR) had the most obvious promothing effects, GA3 and IAA were less effective on seed germination. Seeds of three plant species in the Leymus genus showed differrences in dormancy and germination characters.Degree of the dormancy was associated with plant asexual propagation ability (the development of rhizomes). It implied that seed dormancy in this genus indicated the adaptation patterns of different plants to varied environmental conditions.