表油菜素内酯促进小麦胚芽鞘伸长的作用

BR促进小麦胚芽鞘伸长的生理活性大于IAA,但高浓度的促进现象不如IAA明显。BR刺激乙烯生成与浓度相关。BR和IAA混合处理,对芽鞘切段的伸长、乙烯释放和H~+分泌都表现了加成作用。这二种激素在作用时间上有明显的差别,BR作用的滞后期更为清楚。BR有拮抗ABA对小麦胚芽鞘切段伸长的抑制作用。

Promotion Effect of Epi-brassinolide on the Elongation of Wheat Coleoptiles

Excised coleoptile segments of etiolatedwheat seedlings were used in the experiments.Stimulating effect of epi-brassinolide on theelongation of coleoptiles was greater than thatof IAA at low concentration (<10~(-2)ppm). Howe-ver, at 5 ppm concentration, the promotion of theelongation of segments by epi-brassinolide wasmore than that by IAA (Fig.1). The correla-tion between induction of ethylene productionand epi-brassinolide concentration was not sohigh as with IAA concentration. It was shownthat the effects of epi-brassinolide and IAA areadditive in the enhancement of segment elonga-tion and ethylene production and promotion ofH~+ secretion in coleoptile segments, though thelag phase of IAA-promoted elongation of coleop-tiles was shorter than the epi-brassinolide-pro-moted effect. On the other hand, epi-brassino-lide could have antagonistic action on the inhi-bitive effect of ABA on the elongation of coleptilesegments.