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    Plant Hormones: Auxins
    ::植物激素:

    Auxins: Growth and Apical Dominance
    ::Auxins:增长和光辉主宰

    As the first known regulator, auxin was named after a Greek word for “to grow”. A variety of complex processes are now associated with auxins, but the observation which led to their initial discovery was the bending of plants toward light. Auxins accomplish this plant “movement” by causing elongation/growth on the darker side of the plant ( Figure ). Removal and later replacement of the stem tip showed that this bending depends on a substance produced in the tip; when isolated, the substance named “auxin” proved to be indoleacetic acid , or IAA.
    ::作为第一个已知的监管机构,Auxin是以希腊语命名的“种植”一词命名的。现在,各种复杂的过程都与Auxins有关,但导致最初发现这些过程的观察是植物向光的弯曲。Auxins通过在植物的阴暗面(Figure)造成延长/生长来完成这一工厂的“移动 ” 。清除和后来的更换干尖表明,这种弯曲取决于在尖头中产生的物质;在孤立时,名为“auxin”的物质被证明是非专利酸,或国际宇航科学院。

    The observation that plants “bend” or grow toward light led to the discovery of the first group of plant hormones, auxins. Auxins cause bending by increasing growth and elongation of cells on the dark side of a stem.
    The observation that plants “bend” or grow toward light led to the discovery of the first group of plant hormones, auxins. Auxins cause bending by increasing growth and elongation of cells on the dark side of a stem.

    As early suggested, the tips of stems –  apical meristems – produce the auxin IAA. Both tips and are important for apical dominance – the tendency of most plants to concentrate growth in the terminal bud and suppress growth in lateral buds. In many trees, apical dominance produces the trunk. Botanists do not completely understand the mechanism of apical dominance. According to one hypothesis supported by considerable data, the ratio of auxin to cytokinins determined the level of apical dominance. Plants do actively transport IAA from the terminal buds downward toward the , inhibiting lateral bud , and roots send cytokinin in the opposite direction, stimulating lateral bud growth.
    ::正如早期所暗示的那样,源端的小点 — — 光线短片 — — 产生AATI的副作用。 两种小点和对皮质占优势都很重要 — — 大多数植物倾向于将增长集中在末端芽中,抑制横向芽中的生长。 在许多树木中,皮质占优势产生树干。 植物学家并不完全理解皮质占优势的机制。 根据大量数据支持的一个假设,轴心与细胞基因的比例决定了皮质占优势的程度。 植物确实将工匠从末端芽向下流动,抑制横向芽,根向相反的方向输送细胞基,刺激横向芽增长。

    At low concentrations, IAA promotes cell growth/ elongation in roots and shoots by influencing , activity levels, and membrane ion pumps. At first, cell walls expand. Changes in ion concentrations cause to increase cell volume. Subsequently, activated and newly synthesized enzymes produce new cytoplasm and cell walls for sustained growth. Auxins promote secondary (woody) growth, as well, by stimulating in the cambium . The embryos of seeds produce auxins, promoting the development of fruit – probably through much the same mechanism.
    ::在低浓度条件下,国际宇航科学院通过影响、活动水平和膜离子泵,促进细胞根部和发芽的生长/延长。 首先,细胞壁扩张。 离子浓度的变化导致细胞体积的增加。 随后,激活和新合成的酶为持续增长生产了新的细胞板和细胞壁。 Auxins促进二次(木质)增长,同时通过触角刺激。 种子胚胎产生助产物,促进水果开发 — — 可能通过同样机制。

    At higher concentrations, however, IAA stimulates the formation of ethylene, itself a hormone. Ethylene promotes fruit development, but it inhibits cell elongation in roots and shoots; in effect, high concentrations of IAA have the opposite effect of low concentrations. The relationship between IAA and ethylene is one example of the complexity of interactions among hormones. Another is the synergism between auxin and cytokinins, discussed above. And a third is the inhibitory effect of light on auxin activity – the reason plants grow/bend toward the light is the auxin-induced increase in growth on the darker side of the stem.
    ::然而,在高浓度时,国际宇航科学院刺激了乙烯的形成,这本身就是一种荷尔蒙。 乙烯促进水果开发,但抑制细胞在根部和发芽中的延长;事实上,国际宇航科学院的高浓度具有低浓度的相反效果。国际宇航科学院和乙烯之间的关系是荷尔蒙之间相互作用复杂性的一个例子。另一个例子是上文讨论的轴心与细胞基因之间的协同关系。 第三个是光对助产物活动的抑制效应 — — 植物生长/生长到光线的原因就是树干阴部的生长增加。

    Their growth-stimulating properties have led to commercial use of auxins and synthetic auxins. Vegetative by cutting uses horticultural rooting hormones such as IBA. Note the structural similarity of IBA to IAA; both are “auxins” with similar chemical activity. The use of synthetic auxins such as 2,4 D as broadleaf herbicides, as discussed in the Introduction concept, is based on their stimulation of unsustainable, uncontrolled growth. Finally, auxins can help to grow fruits such as tomatoes. Spraying auxins on flowers eliminates the need for pollination , normally required for auxin production by seeds. An added benefit, if the fruits are for consumption, is that these fruits may be seedless.
    ::其刺激生长的特性已导致对助产物和合成助产物的商业利用。通过切除使用园艺根生激素如IBA来种植。注意IBA与IAA的结构性相似性;两者都是具有类似化学活动的“辅助物 ” ;正如在导言概念中所讨论的,合成助产物如2,4D作为宽叶素除草剂的使用是基于对不可持续、无节制增长的刺激。最后,助产物可以帮助种植番茄等水果。在花朵上喷洒助产物可以消除对授粉的需求,通常这是用种子生产助产物所需要的。如果水果是用于消费,则增加的好处是这些水果可能没有种子。

    Summary
    ::摘要

    • An auxin that helps plants bend toward light was the first plant hormone discovered.
      ::帮助植物向光向弯曲的助燃剂 是第一个发现的植物荷尔蒙
    • The ratio of inhibitory auxins to stimulating cytokinins determines the development of lateral buds.
      ::抑制性抗原与刺激性细胞基因的比例决定了横向芽的发育。
    • Auxins promote elongation/growth of cells in relative darkness to cause the bending-toward-light response.
      ::助力在相对黑暗的情况下促进细胞的延长/生长,以引起弯曲至向光的响应。
    • Auxins stimulate secondary growth in stems/trunks; auxin produced by embryos promotes fruit development.
      ::Auxins刺激了根茎/树苗的二次增长;胚胎生产的Auxins促进水果开发。
    • Auxin interacts with light and promotes formation of ethylene. Ethylene and cytokinins are auxin antagonists.
      ::Axin与光相互作用,促进乙烯的形成,乙烯和cytokinins是苯对抗者。
    • Auxins promote fruit development in the absence of seeds, root development in cuttings, and weed killing.
      ::Auxins在没有种子的情况下促进水果开发,在切除和除草中从根本上发展。
    • Together with auxin, cytokinins regulate cell division and differentiation.
      ::细胞基因与附着物一道,对细胞分裂和差异进行调节。
    • When the ratio of cytokinin to auxin favors cytokinin, shoots and buds develop; if auxin, roots develop.
      ::当cytokinin与auxin的比例 有利于cytokinin, 射击和芽发展; 如果auxin, 根发展。
    • Cytokinins from roots act as antagonists to auxin in apical dominance, promoting lateral bud growth.
      ::根部的阴茎会起对抗作用,成为针锋相对占优势的副手,促进横向芽生长。