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 etiolated wheat seedlings were used in the experiments. Stimulating effect of epi-brassinolide on the elongation of coleoptiles was greater than that of IAA at low concentration (<10~(-2)ppm). Howe- ver, at 5 ppm concentration, the promotion of the elongation of segments by epi-brassinolide was more than that by IAA (Fig.1). The correla- tion between induction of ethylene production and epi-brassinolide concentration was not so high as with IAA concentration. It was shown that the effects of epi-brassinolide and IAA are additive in the enhancement of segment elonga- tion and ethylene production and promotion of H~+ secretion in coleoptile segments, though the lag 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 coleptile segments.