细胞分裂素促进小麦硝酸还原酶的诱导

细胞分裂素促进硝酸还原酶的诱导,脱落酸强烈抑制该酶的诱导,并抵消细胞分裂素的作用。6-苄基腺瞟呤(6-BA)的促进效应与 NO_3~-的诱导作用有关。无 NO_3~-存在时,6-BA 无直接诱导作用,适宜浓度的 NO_3~-可诱导较高的酶活性,这时6-BA 的促进作用也较强。无光照时,NO_3~-只能诱导黄化叶片产生很低的酶活性,这时6-BA 的促进作用也很弱。在1—2小时的诱导期内,环己酰亚胺抑制酶的诱导。结果表明细胞分裂素对酶诱导的促进作用不仅与 NO_3~-的存在有关,还与 NO_3~-诱导硝酸还原酶的必要条件有关,即依赖于酶的诱导过程。

THE ACCELERATIVE EFFECTS OF CYTOKININ ON NITRATE REDUCTASE INDUCTION

Cytokinin stimulates the induction of nitrate reductase(EC 1.6.6.1,NR)ABT inhibites the induction of NR and counteractes the effect of 6-benzyladenine(6-BA)on the induction of NR.6-BA alone could not induce NR activity and the effect of 6-BA became stranger when ap- propriate concentration of NO_3~- induced higher NR activity.In the dark a little NR activity was induced by NO_3~- in etiolated leaves and the effect of 6-BA was very weak at the same con- dition.Cycloheximide depresses the induction of NR by NO_3~-.These results showed that the accelerative effects of cytokinin on NR induction was a indirect action depending on NR inducing process rather than on the presence of NO_3~- alone.