Hydrogen, carbon and nitrogen isotopic fractionations during chlorophyll biosynthesis in C3 higher plants
Hydrogen, carbon and nitrogen isotopic fractionations during chlorophyll biosynthesis in C3 higher plants
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DOI：
10.1016/j.phytochem.2005.03.004
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发表时间：
2005-04-01
期刊：
影响因子：
3.8
通讯作者：
Ohkouchi, N
中科院分区：
文献类型：
--
作者：
Chikaraishi, Y;Matsumoto, K;Ohkouchi, N
本文测定了5种C3高等植物（Benthantidiajaponica、Primitsjaponica、carpinifolium、Acer argutum和Querus mongloica）叶片叶绿素a和叶绿素b的氢、碳、氮同位素组成，以及叶绿素中叶绿醇和叶绿素内酯的氢、碳同位素组成，以了解这些植物叶绿素生物合成的同位素分异。叶绿素在D中相对于环境水的损耗约为189‰，在C-13中相对于散装组织的富集约为1.6‰。这些数据可以用叶绿醇和叶绿内酯生物合成过程中同位素分馏的贡献来解释。叶绿醇在D（类似于308‰）和C-13（类似于4.3‰）中的耗竭更大，而叶绿素素在D（类似于44%‰）中的耗竭更少，在C-13中富集（类似于4.8‰）。叶绿素中同位素分布的不均匀性表明：(1)在甲基赤藓糖醇磷酸途径中，由于同位素分异导致叶绿素中的D-和c -13的强烈消耗，然后是加氢；(2)在三羧酸循环中，叶绿素内酯反映了D-和（13）根富集。另一方面，叶绿素在N-15中相对于整体组织略有减少（类似于1.2‰），这表明叶绿素生物合成过程中氮的净同位素分异与氢和碳的净同位素分异相比较小。(c) 2005 Elsevier Ltd版权所有。
We determined hydrogen, carbon and nitrogen isotopic compositions of chlorophylls a and b isolated from leaves of five C3 higher plant species (Benthantidiajaponica, Primitsjaponica, Acer carpinifolium, Acer argutum and Querus mongloica), and hydrogen and carbon isotopic compositions of phytol and chlorophyllides in the chlorophylls to understand isotopic fractionations associated with chlorophyll biosynthesis in these species. Chlorophylls are depleted in D relative to ambient water by similar to 189 parts per thousand and enriched in C-13 relative to bulk tissue by similar to 1.6 parts per thousand. These data can be explained by the contribution of isotopic fractionations during phytol and chlorophyllide biosyntheses. Phytol is more depleted in both D (by similar to 308 parts per thousand) and C-13 (by similar to 4.3 parts per thousand), while chlorophyllides are less depleted in D (by parts per thousand 44%.) and enriched in C-13 (by similar to 4.8 parts per thousand). Such inhomogeneous distribution of isotopes in chlorophylls suggests that (1) the phytol in chlorophylls reflects strong D- and C-13-depletions due to the isotopic fractionations during the methylerythritol phosphate pathway followed by hydrogenation, and (2) the chlorophyllides reflect D- and (13)Genrichments in tricarboxylic acid cycle. On the other hand, chlorophylls are slightly (similar to 1.2 parts per thousand) depleted in N-15 relative to the bulk tissue, indicating that net isotopic fractionation of nitrogen during chlorophyll biosynthesis is small compared with those of hydrogen and carbon. (c) 2005 Elsevier Ltd. All rights reserved.