Gravity-regulated formation of the peg in developing cucumber seedlings
Gravity-regulated formation of the peg in developing cucumber seedlings
复制标题
黄瓜幼苗发育过程中重力调节的桩的形成
作者：
Hideyuki Takahashi;T. K. Scott
葫芦科植物幼苗下胚轴与根部之间维管过渡区（TR区）的peg形成是一种重力形态发生现象。在吸胀36 h后，黄瓜(Cucumis sativusL。简历。杂交Burpee II)种子在24°C的水平位置在黑暗中萌发。同时，在血管束周围的鞘细胞和紧挨着它们的皮层细胞中，在TR区，沉积的淀粉体（假定的静石）很明显。相比之下，其他皮层细胞，其中一些注定要发育成peg，含有没有沉淀的淀粉体。这些结果表明，聚钉形成的重力感知机制可能类似于茎状向重力作用中的statoliths。吸胀后48 h， TR区的细胞仍有淀粉体沉积，但可能由于其成熟而失去了对重力的敏感性。
It has been proposed that peg formation in the vascular transition region (TR zone) between the hypocotyl and the root in Cucurbitaceae seedlings is a gravimorphogenetic phenomenon. Initiation of the peg became visible 36 h after imbibition when cucumber (Cucumis sativusL. cv. Burpee Hybrid II) seeds were germinated in a horizontal position at 24°C in the dark. Simultaneously, sedimented amyloplasts (putative statoliths) were apparent in the sheath cells surrounding the vascular strands, and in the cortical cells immediately adjacent to them, in the TR zone. In contrast, the other cortical cells, some of which were destined to develop into the peg, contained amyloplasts which were not sedimented. These results suggest that the graviperception mechanism for peg formation may be like that of statoliths in shoot gravitropism. By 48 h following imbibition, the cells of the TR zone still had sedimented amyloplasts but had lost their sensitivity to gravity, possibly because of their maturation.