THE POLARITY OF AUXIN TRANSPORT
THE POLARITY OF AUXIN TRANSPORT
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生长素运输的极性
DOI：
10.1111/j.1749-6632.1967.tb34004.x
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发表时间：
1967
影响因子：
5.2
通讯作者：
R. K. Fuente
中科院分区：
文献类型：
--
作者：
A. Leopold;R. K. Fuente
当细胞接受激素指令继续生长时，它们的反应，在茎和胚芽鞘的情况下，是极性类型的伸长。同样地，当激素信使在茎中移动并影响诸如顶端优势、向性生长和生根等相关功能时，系统调节功能在茎中表现出极性。从它被发现的时候起，生长素就已经知道以极性的方式通过茎和胚芽鞘，这种极性的运输似乎是生长素对生长和发育的极性影响的基础。因此，运输生长素的系统具有非常特殊的意义：（a）作为涉及主要激素的主动运输，（B）作为生长和发育的主要系统调节剂的调度系统，和（c）作为植物细胞基本极性的表达。鉴于其对植物生长的影响，令人困惑的是，我们对生长素运输是如何实现的知之甚少。货车·德·魏伊（1932）做出了一些重要贡献，他主要确定了在向基方向上的输运是强极性的，并且它以明显超过扩散的速度进行。现在已知它具有主动运输系统的所有特征，包括对吲哚乙酸和极少数其他生长素的强特异性，对代谢能的显著依赖性，以及明显地逆着浓度梯度运输生长素的能力（Leopold，1963）。事实上，这是一个积极的运输过程意味着它涉及运输通过一些膜屏障，和最近的证据表明，生长素运输涉及分泌的生长素细胞（Hertel和Leopold，1963）表明，泵的生长素跨越横壁可能是一个基本要素在极性运输系统。温特（Went，1932）提出了一个早期的建议，杜·布伊（du Buy）和奥尔森（Olson，1940）进一步发展了这一建议，即生长素的运输可能由两种载体组成，一种是通过细胞质运输（可能是通过细胞质流），另一种是通过茎或胚芽鞘的横壁运输。我们想进一步发展这个模型，利用一些新的测量传输参数，努力分配系统的每一个主要特征，这两个组件。
When cells receive the hormonal directive to proceed with growth, they respond, in the case of stems and coleoptiles, with a polar type of elongation. Similarly, as the hormonal messenger moves through stems and there influences such correlative functions as apical dominance, tropistic growth and rooting, the systemic regulatory function displays a polarity down the stem. From the time of its discovery, auxin has been known to travel through stems and coleoptiles in a polar manner, and this polarity of transport appears to be the basis for the polar influences of auxins on growth and development. The system by which auxin is transported therefore takes on very special significance (a ) as an active transport involving a major hormone, (b) as a dispatching system for a major systemic regulator of growth and development, and (c) as an expression of the basic polarity of the plant cell. In view of its impact on plant growth, it is perplexing that we know so little about how auxin transport is achieved. Some major contributions were made by van der Weij (1932), who established principally that the transport is strongly polar in the basipetal direction, and that it proceeds with a velocity markedly in excess of diffusion. It is now known to have all of the features of an active transport system, including a strong specificity for indoleacetic acid and a very few other auxins, a marked dependence upon metabolic energy, and the ability to apparently transport the auxin against a concentration gradient (Leopold, 1963). The fact that it is an active transport process implies that it involves a transport across some membrane barrier, and recent evidence that auxin transport involves a secretion of auxin out of cells (Hertel & Leopold, 1963) suggests that the pumping of auxin across cross-walls may be a basic element in the polar transport system. An early suggestion was made by Went (1932), and developed further by du Buy and Olson (1940), that auxin transport might be composed of two vectors, a transit across the cytoplasm (perhaps by cytoplasmic streaming), and a transit across the cross-walls of a stem or coleoptile. We would like to develop this model further, utilizing some new measurements of transport parameters in an effort to assign each of the major characteristics of the system to these two components.