细胞分裂素的作用在拟南芥幼苗中对根和下胚轴伸长的抑制作用方面与乙烯相关联。
Cytokinin action is coupled to ethylene in its effects on the inhibition of root and hypocotyl elongation in Arabidopsis thaliana seedlings.
作者信息
Cary A J, Liu W, Howell S H
机构信息
Boyce Thompson Institute, Cornell University, Ithaca, New York 14853, USA.
出版信息
Plant Physiol. 1995 Apr;107(4):1075-82. doi: 10.1104/pp.107.4.1075.
Cytokinins have profound effects on seedling development in Arabidopsis thaliana. Benzyladenine (BA) inhibits root elongation in light- or dark-grown seedlings, and in dark-grown seedlings BA inhibits hypocotyl elongation and exaggerates the curvature of apical hooks. The latter are characteristic ethylene responses and, therefore, the possible involvement of ethylene in BA responses was examined in seedlings. It was found that the inhibitory effects of BA on root and hypocotyl elongation were partially blocked by the action of ethylene inhibitors or ethylene-resistant mutations (ein1-1 and ein2-1). Ethylene production was stimulated by submicromolar concentrations of BA and could account, in part, for the inhibition of root and hypocotyl elongation. It was demonstrated further that BA did not affect the sensitivity of seedlings to ethylene. Thus, the effect of cytokinin on root and hypocotyl elongation in Arabidopsis appears to be mediated largely by the production of ethylene. The coupling between cytokinin and ethylene responses is further supported by the discovery that the cytokinin-resistant mutant ckr1 is resistant to ethylene and is allelic to the ethylene-resistant mutant ein2.
细胞分裂素对拟南芥幼苗发育具有深远影响。苄基腺嘌呤（BA）抑制光照或黑暗条件下生长的幼苗的根伸长，并且在黑暗中生长的幼苗中，BA抑制下胚轴伸长并加剧顶端弯钩的弯曲度。后者是典型的乙烯反应，因此，研究了乙烯在BA反应中可能的参与情况。结果发现，BA对根和下胚轴伸长的抑制作用被乙烯抑制剂或乙烯抗性突变（ein1-1和ein2-1）部分阻断。亚微摩尔浓度的BA刺激乙烯产生，这可能部分解释了对根和下胚轴伸长的抑制作用。进一步证明，BA不影响幼苗对乙烯的敏感性。因此，细胞分裂素对拟南芥根和下胚轴伸长的影响似乎主要由乙烯产生介导。细胞分裂素抗性突变体ckr1对乙烯具有抗性且与乙烯抗性突变体ein2等位，这一发现进一步支持了细胞分裂素和乙烯反应之间的联系。
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