Ketsa Saichol, Wisutiamonkul Apinya, van Doorn Wouter G
Department of Horticulture, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand.
Wageningen University and Research Centre, PO Box 17, 6700AA Wageningen, The Netherlands.
Funct Plant Biol. 2006 Sep;33(9):887-892. doi: 10.1071/FP06034.
In Dendrobium and other orchids the ovule becomes mature long after pollination, whereas the ovary starts growing within two days of pollination. The signalling pathway that induces rapid ovary growth after pollination has remained elusive. We placed the auxin antagonist α-(p-chlorophenoxy) isobutyric acid (PCIB) or the auxin transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) on the stigma, before pollination. Both treatments nullified pollination-induced ovary growth. The ovaries also did not grow after similar stigma treatment with 1-methylcyclopropene (1-MCP), AgNO (both inhibitors of ethylene action), aminooxyacetic acid (AOA) or CoCl (which both inhibit ethylene synthesis), before pollination. Pollination could be replaced by placement of the auxin naphthylacetic acid (NAA) on the stigma. All mentioned inhibitors nullified the effect of NAA, indicating that if auxin is the initiator of ovary growth, it acts through ethylene. The results suggest that the pollination effect on ovary growth requires auxin (at least auxin transport and maybe also auxin signalling), and both ethylene synthesis and ethylene action.
在石斛及其他兰花中，胚珠在授粉后很长时间才成熟，而子房在授粉后两天内就开始生长。授粉后诱导子房快速生长的信号通路一直难以捉摸。我们在授粉前将生长素拮抗剂α-（对氯苯氧基）异丁酸（PCIB）或生长素运输抑制剂2,3,5-三碘苯甲酸（TIBA）置于柱头上。两种处理均使授粉诱导的子房生长无效。在授粉前，用1-甲基环丙烯（1-MCP）、硝酸银（两者均为乙烯作用抑制剂）、氨基氧乙酸（AOA）或氯化钴（两者均抑制乙烯合成）对柱头进行类似处理后，子房也不生长。用生长素萘乙酸（NAA）置于柱头上可替代授粉。所有上述抑制剂均使NAA的作用无效，这表明如果生长素是子房生长的启动因子，它是通过乙烯起作用的。结果表明，授粉对子房生长的影响需要生长素（至少是生长素运输，也可能还有生长素信号传导），以及乙烯合成和乙烯作用。
