33.コムギの深播き耐性機構 : ジベレリンによる第一節間伸長促進に必要な表皮の細胞伸長と皮層の細胞増殖(口頭発表)

概要

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Wheat seedlings elongate their first internode to elevate the shoot apical meristem toward the soil surface when seeds are sown deep in the soil. We have shown that Hong Mang Mai wheat (HMM) elongates its first internode at an extreme rate and is able to emerge from much deeper soil than do others because of its super-responsiveness to GA. To understand the mechanisms underlying the deep-sowing tolerance of HMM, we investigated the effect of GA on cell elongation and cell proliferation in the first internode of HMM and compared them to those of ordinary cultivar with altered responsiveness to GA, namely Hope. In both HMM and Hope, GA treatment hardly affected cell length in cortical tissue, whereas its cell number increased in response to GA. In epidermis of the GA-treated first internodes, on the other hand, cell elongation was accelerated, whereas there was no substantial change in cell number. The enhanced rates of elongation of epidermal cells and proliferation of cortical cells due to GA treatment was greater in HMM, compared to those in Hope. These results suggest that in the GA-treated seedlings of wheat elongation of epidermal cells and proliferation of cortical cells collaborate for making first internode longer. The first internodes of HMM may possess the pronounced GA effects on cell elongation and proliferation, which could exert tolerance to deep-sowing conditions.
植物化学調節学会の論文
2008-10-06