Abscisic acid in the xylem: where does it come from, where does it go to?
Abscisic acid in the xylem: where does it come from, where does it go to?
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DOI：
10.1093/jexbot/53.366.27
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发表时间：
2002-01-01
影响因子：
6.9
通讯作者：
Hose, E
中科院分区：
文献类型：
--
作者：
Hartung, W;Sauter, A;Hose, E
脱落酸是一种激素胁迫信号，其在木质部中从根移动到芽的不同部分，在那里它调节蒸腾水分损失和叶片生长。改变木质部中阿坝信号强度的因素特别令人感兴趣，因为靶细胞识别浓度。阿坝（xyl），将减少通过根的径向水流量增加，假设径向阿坝运输只发生在共质体。植物激素浓度的这种稀释可以以不同的方式补偿，这有助于保持木质部中ABA浓度恒定：（i）阿坝的质外体旁路流动，（ii）运输期间阿坝在茎薄壁组织和木质部之间流动，以及（iii）β-D-葡糖苷酶的作用，其将游离阿坝从其缀合物释放到根皮层和叶质外体。讨论了ABA的反射系数（sigma（阿坝））、膜透性系数（P-S（阿坝））和质外体屏障的意义。
Abscisic acid is a hormonal stress signal that moves in the xylem from the root to the different parts of the shoot where it regulates transpirational water loss and leaf growth. The factors that modify the intensity of the ABA signal in the xylem are of particular interest because target cells recognize concentrations. ABA(xyl), will be decreased as radial water flow through the roots is increased, assuming that radial ABA transport occurs in the symplast only. Such dilutions of the plant hormone concentration can be compensated in different ways, which help to keep the ABA-concentrations in the xylem constant: (i) apoplastic bypass flows of ABA, (ii) ABA flows between the stem parenchyma and the xylem during transport and (iii) the action of beta -D-glucosidases that release free ABA from its conjugates to the root cortex and the leaf apoplast. The significance of reflection coefficients (sigma (ABA)), permeability coefficients of membranes (P-S(ABA)) and apoplastic barriers for ABA is discussed.