Subcellular organization and metabolic activity during the development of seeds that attain different levels of desiccation tolerance
Subcellular organization and metabolic activity during the development of seeds that attain different levels of desiccation tolerance
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DOI：
10.1017/s0960258500003470
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发表时间：
1997-06-01
影响因子：
2.1
通讯作者：
Walters, C
中科院分区：
文献类型：
--
作者：
Farrant, JM;Pammenter, NW;Walters, C
对3种不同类型种子发育过程中的含水率、脱水耐性、呼吸速率和亚细胞特性进行了研究。白骨壤(热带湿地物种)和七叶树(温带物种)产生顽固的种子，普通菜豆产生正统种子。在种子发育过程中，种子的含水率和呼吸强度下降，耐脱水能力增强。这些参数在海滨冰草种子一旦萌发后的发育过程中没有改变。种子液泡化程度降低，不溶储藏增加，而滨海相思种子液泡化程度较高，不积累不溶储藏。红豆杉和普通红豆杉种子在发育过程中线粒体和内膜退化，而滨海参种子的线粒体和内膜保持不变。这些数据与广泛的空泡化和高代谢率有助于干燥敏感性的假设是一致的。然而，顽固的红豆杉种子的发育与正统的红豆杉种子相似。这些数据与种子顽抗是截断发育的结果的概念是一致的。结果表明，种子可分为三类：具有脱水耐性的正统种子，发育与正统种子相似的种子，但在脱水耐性发育良好之前脱落的种子，以及无发育趋势而导致耐性增强的种子。
Water contents, desiccation tolerance, respiratory rates and subcellular characteristics of three contrasting seed types were studied during development. Avicennia marina (a tropical wetland species) and Aesculus hippocastanum (a temperate species) produce recalcitrant seeds and Phaseolus vulgaris produces orthodox seeds. During development, A. hippocastanum and P. vulgaris seeds showed a decline in water content and respiration rate with a concomitant increase in desiccation tolerance. These parameters did not change during the development of A. marina seeds once they had become germinable. There was a decrease in the degree of vacuolation and an increase in the deposition of insoluble reserves in A. hippocastanum and P. vulgaris seeds, while A. marina seeds remained highly vacuolated and did not accumulate insoluble reserves. Mitochondria and endomembranes degenerated during the development of A. hippocastanum and P. vulgaris seeds, but remained unchanged in A. marina seeds. The data are consistent with the hypothesis that extensive vacuolation and high metabolic rates contribute to desiccation sensitivity. However, the development of recalcitrant A. hippocastanum seeds is similar to that of orthodox P. vulgaris seeds. These data are in accord with the concept of seed recalcitrance being a consequence of truncated development. The results suggest that there may be three categories of seeds: orthodox seeds which develop desiccation tolerance, seeds which show similar development to orthodox seeds, but are shed before desiccation tolerance is well developed, and seeds which show no developmental trends giving rise to increased tolerance.