Grover S, Purves W K
Department of Biology, University of California, Los Angeles, California 90024.
Plant Physiol. 1976 Jun;57(6):886-9. doi: 10.1104/pp.57.6.886.
Co(2+) promoted elongation of hypocotyl segments of light-grown cucumber (Cucumis sativus) seedlings. Time course and dose response data are presented and interactions with IAA, gibberellin, cyclohexanol, and cotyledons described. Segments without cotyledons responded to Co(2+) only if grown in gas-tight vessels with IAA added. When bases of cotyledons were ringed with an inhibitor of auxin transport, Co(2+) caused no growth promotion in the hypocotyl. Co(2+) prevented lateral swelling of hypocotyls treated with supraoptimal IAA. Removal of ethylene from the atmosphere reduced the Co(2+) response, but Co(2+) did not counteract the inhibitory effect of increased ethylene levels. These results are consistent with the hypothesis that Co(2+) promotes hypocotyl elongation by inhibiting ethylene production. The hypothesis was confirmed by a direct demonstration that Co(2+), at growth-promoting concentrations, powerfully inhibited ethylene production in the cucumber hypocotyl.
钴离子（Co²⁺）促进了在光照下生长的黄瓜（Cucumis sativus）幼苗下胚轴切段的伸长。文中给出了时间进程和剂量反应数据，并描述了其与生长素（IAA）、赤霉素、环己醇和子叶的相互作用。没有子叶的切段只有在添加了IAA的气密容器中生长时才会对Co²⁺产生反应。当用生长素运输抑制剂环绕子叶基部时，Co²⁺不会促进下胚轴的生长。Co²⁺可防止用超最适浓度IAA处理的下胚轴横向肿胀。去除大气中的乙烯会降低Co²⁺反应，但Co²⁺不会抵消乙烯水平升高的抑制作用。这些结果与Co²⁺通过抑制乙烯产生来促进下胚轴伸长的假说一致。通过直接证明在促进生长的浓度下Co²⁺能强烈抑制黄瓜下胚轴中的乙烯产生，该假说得到了证实。
