表油菜素内酯对绿豆上胚轴内源IAA及其氧化酶的影响

Effects of Epibrassinolide on Endogenous IAA and Its Oxidase in Epicotyls of Mung Bean Seedlings

用0.5ppm表油菜素内酯处理绿豆幼苗,显著促进上胚轴伸长生长,若切除真叶则可抑制表油菜素内酯诱导的效应。三碘苯甲酸(TIBA)也可抑制表油菜素内酯促进的伸长生长。外源IAA能部分恢复TIBA的抑制效应。经处理的上胚轴内源IAA含量明显高于对照。暗示表油菜素内酯可能通过对内源IAA的调节来促进绿豆上胚轴的伸长生长。 表油菜素内酯处理的绿豆上胚轴组织中,与生长素降解密切相关的IAA氧化酶以及过氧化物酶活性均明显低于对照。

The growth of mung bean epicotyl was markedly increased by treatment with epibrassinolide (0.5 ppm) on 1-week-old seedlings for 48 h (Fig. 1). However, this effect was lost when some of the leaves were removed (Fig. 2). TIBA (an inhibitor of polar transport of IAA) also inhibited the growth of mung bean epicotyl induced by epibrassinolide (Fig. 3). When the seedlings were treated with exogenous IAA, together with epibrassinolide and TIBA, IAA partly counteracted the inhibition of TIBA on mung bean epicotyl growth induced by epibrassinolide (Fig. 4). Epibrassinolide significantly increased the content of IAA in mung bean epicotyl (Fig. 5). It was concluded that epibrassinolide probably promoted the growth of mung bean epicotyl through the enhancement of endogenous IAA level. The activities of peroxidase and IAA oxidase which had close relation to the metabolism of IAA were ihinbited with the treatment of epibrassinolide (Figs. 6,7). It suggested that epibrassinolide could probably increase the level of endogenous IAA by the inhibition of peroxidase and oxidase.