FURTHER EVIDENCE FOR OSMOREGULATION IN EPIDERMAL LEAF CELLS OF SEAGRASSES
FURTHER EVIDENCE FOR OSMOREGULATION IN EPIDERMAL LEAF CELLS OF SEAGRASSES
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海草表皮叶细胞渗透压调节的进一步证据
DOI：
10.1002/j.1537-2197.1983.tb06399.x
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
R. Jagels
中科院分区：
文献类型：
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作者：
R. Jagels
对三种海草，即海草（热带，高盐度）、海草（北温带，中等盐度）和海草（北温带，微咸）的表皮叶细胞超微结构的比较，证实了内陷的质粒-线粒体运输系统至少在一定程度上是对盐浓度的反应。假设的Cl-离子的细胞化学定位为盐分泌或排除机制的存在提供了进一步的证据。未成熟的表皮叶细胞通过大量的胞间连丝相互交流，并与叶肉细胞交流，但在细胞成熟过程中，这些细胞质连接丢失，胞外转运系统发育以取代共塑运输系统。这两种北温带海草含有热带海草所没有的细胞质脂质。海藻和小藻的叶绿体缺乏淀粉，但用硫代碳酰肼染色多糖。红藻叶绿体的多糖染色基本上是阴性的，但这种半咸水物种的叶肉叶绿体含有淀粉。这些和其他细胞学结果与其他海草进行比较。在早期的一篇论文中，有人提出海草海草的表皮叶细胞具有渗透调节作用（Jagels, 1973）。支持这一理论的证据包括：1)高膜电位的证明；2)与其他分泌细胞系统中发现的结构类似的，带有交错线粒体的卷曲质膜的发现。在本文中，提出了支持渗透调节的其他两种证据。一种方法涉及钠离子或氯离子的超微结构定位，以记录盐的分配。另一种方法涉及比较超微结构研究，predi
A comparison of the epidermal leafcell ultrastructure ofthree seagrasses, Thalassia testudinum (tropical, high salinity), Zostera marina (North temperate, moderate salinity), and Ruppia maritima (North temperate, brackish) provides confirmation for the theory that an invaginated plasmalemma-mitochondrial transport system is developed at least in part as a response to salt concentration. Cytochemical localization of presumed Cl- ion provides further evidence for the presence of a salt secretion or exclusion mechanism. Immature epidermal leaf cells communicate with each other and with mesophyll cells through numerous plasmodesmata, but during cell maturation these cytoplasmic connections are lost and the apoplastic transport system develops to replace the symplastic one. The two North temperate region seagrasses contain cytoplasmic lipids which are absent in the tropical species. Thalassia and Zostera have chloroplasts which lack starch, but stain densely for polysaccharides with thiocarbohydrazide. The polysaccharide staining is essentially negative in the chloroplasts of Ruppia, but mesophyll chloroplasts of this brackish water species contain starch. These and other cytological findings are compared with other seagrasses. IN AN EARLIER PAPER it was proposed that the epidermal leaf cells of the seagrass Thalassia testudinum are osmoregulatory (Jagels, 1973). The evidence presented to support that theory consisted of 1) demonstration of a high membrane potential, and 2) discovery of a convoluted plasmalemma with interdigitated mitochondria, analogous to structures found in other secretory cell systems. In this paper two other lines of evidence are presented in support of osmoregulation. One approach involves the ultrastructural localization of sodium or chloride ions to document salt partitioning. The other approach involves a comparative ultrastructural study, predi