Soga Kouichi, Wakabayashi Kazuyuki, Kamisaka Seiichiro, Hoson Takayuki
Department of Biological Sciences, Graduate School of Science, Osaka City University, Osaka, Japan.
Funct Plant Biol. 2005;32(2):175-9. doi: 10.1071/fp04145.
Elongation of primary roots of azuki bean (Vigna angularis Ohwi et Ohashi) was suppressed under hypergravity conditions produced by centrifugation, such that the growth rate decreased in proportion to the logarithm of the magnitude of the gravity. The removal of the root cap did not influence the hypergravity-induced inhibition of root growth, although it completely inhibited the gravitropic root curvature. Lanthanum and gadolinium, blockers of mechanoreceptors, nullified the growth-inhibitory effect of hypergravity. These results suggest that the gravity signal for the hypergravity-induced inhibition of root growth is perceived independently from that of gravitropism, which involves amyloplasts as statoliths. Horizontal and basipetal hypergravity suppressed root growth as did acropetal hypergravity, all of which were nullified by the presence of lanthanum or gadolinium. These findings suggest that mechanoreceptors on the plasma membrane perceive the gravity signal independently of the direction of the stimuli and roots may utilise it to regulate their growth rate.
在离心产生的超重力条件下，赤豆（Vigna angularis Ohwi et Ohashi）初生根的伸长受到抑制，其生长速率与重力大小的对数成比例下降。去除根冠虽完全抑制了根的向地性弯曲，但不影响超重力诱导的根生长抑制。镧和钆作为机械感受器阻滞剂，消除了超重力的生长抑制作用。这些结果表明，超重力诱导根生长抑制的重力信号与涉及淀粉体作为平衡石的向地性重力信号的感知方式相互独立。水平和向基超重力与向顶超重力一样抑制根生长，而镧或钆的存在均消除了这些抑制作用。这些发现表明，质膜上的机械感受器可独立于刺激方向感知重力信号，并且根可能利用该信号来调节其生长速率。
