The last step of the ethylene biosynthesis pathway in turnip tops (Brassica rapa) seeds: Alterations related to development and germination and its inhibition during desiccation.
The last step of the ethylene biosynthesis pathway in turnip tops (Brassica rapa) seeds: Alterations related to development and germination and its inhibition during desiccation.
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萝卜顶部（Brassica rapa）种子乙烯生物合成途径的最后一步：与发育和发芽相关的改变及其在干燥过程中的抑制。
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
A. Matilla
中科院分区：
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作者：
María del Carmen Rodriguez;A. Matilla
乙烯参与合子胚发生是高等植物生长发育中一个鲜为人知的方面。以芜菁为材料，研究了芜菁茎尖形成过程中乙烯生物合成途径最后一步的变化。芜菁种子及其在萌发过程和萌发后生长中的影响。为此，我们选择了角果发育的11个不同阶段，第一个是最近受精的雌蕊，最后一个是角果在其开裂之前（约。开花后2个月）。在这11个阶段中，乙烯的产生在整个角果（有或没有种子）和角果壁包围的种子中检测到。ACC、ACO和乙烯的产生水平在属于以下类型的种子中被证明是高的：（1）在非常早期阶段的豆荚，此时种子正在生长但没有光合能力;（2）在最大生长期的角果，此时种子将开始干燥和失去光合活性。在开裂前的阶段，乙烯生物合成途径的最后一步有一个显着的抑制。在可行的干种子，没有ACO活性检测和ACC水平比角果衰老的开始时低4倍。发芽导致ACC的净合成相对于存储的干种子。这一事实，连同在这项工作中提出的其他结果，指向，在其他种子，乙烯合成的依赖胚根出现。角果壁在合子胚发生过程中乙烯生物合成的控制中可能发挥的作用，以及乙烯作为激素信号参与触发芜菁种子脱水。拉帕，进行了深入讨论。
The involvement of ethylene in zygotic embryogenesis is a little known aspect of the growth and development in higher plants. In the present work, we study the alterations of the last step of the ethylene biosynthesis pathway during the formation period of turnip tops (Brassica rapa cv. Rapa) seeds and its repercussions in the germination process and post-germinative growth. For this, we chose 11 different phases of silique development, the first being the recently fertilized pistil and the last being the silique just prior to its dehiscence (ca. 2 months post-anthesis). In the 11 phases, ethylene production was detected in both whole silique (with or without seeds) and in the seeds enclosed by the silique wall. The levels of ACC, ACO and ethylene production proved high in seeds belonging to: (1) the pod in the very early phases, when the seeds were growing but without photosynthetic competence; (2) the silique at maximum growth, in which the seeds will initiate desiccation and loss of photosynthetic activity. During the phases prior to dehiscence, there was a marked inhibition in the last step of the ethylene biosynthesis pathway. In viable dry seeds, no ACO activity was detected and the ACC levels were 4-fold lower than at the onset of the silique senescence. Germination brings about a net synthesis of ACC with respect of the stores dry seed. This fact, together with other results presented in this work, point towards, as in other seeds, a dependence of ethylene synthesis for radicle emergence. The possible role played by the silique wall in the control of ethylene biosynthesis during zygotic embryogenesis, as well as the participation of ethylene as a hormonal signal in the triggering of seed desiccation in Brassica rapa cv. Rapa, are discussed in depth.