Folate distribution during higher plant development
Folate distribution during higher plant development
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DOI：
10.1002/jsfa.870
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发表时间：
2001-07-01
影响因子：
4.1
通讯作者：
Rébeillé, F
中科院分区：
文献类型：
--
作者：
Gambonnet, B;Jabrin, S;Rébeillé, F
使用微生物测定法测定豌豆幼苗各种组织的总叶酸含量。在种子中，大部分叶酸位于子叶中，但仅占种子总鲜重 2% 的胚的叶酸浓度大约高出三倍。在存在磺胺（一种叶酸生物合成抑制剂）的情况下，最初的叶酸含量在前 1-2 天内支持根的伸长。然而，幼苗的进一步生长是不可能的，并且需要叶酸的从头合成。器官发生后，幼根和芽的叶酸含量与初始胚胎中的叶酸含量相似。相比之下，幼叶的叶酸含量在生长7天后迅速增加，达到其他组织的两到三倍，此后基本保持不变。评估 12 天龄叶片中叶酸的细胞内分布。线粒体是叶酸合成的场所，约占细胞叶酸总量的 30%。叶绿体中的叶酸水平比线粒体中的叶酸水平低约 100 倍，按蛋白质计算，叶酸含量不到总叶酸水平的 4%。我们将大部分叶酸与细胞质和细胞核（池的 65-70%）联系起来，尽管线粒体（小于细胞质体积的 5%）浓度最高。以鲜重计，为什么叶子中的叶酸含量比其他组织中的叶酸含量还不清楚。参与光呼吸的叶酸依赖性酶（甘氨酸脱羧酶和丝氨酸羟甲基转移酶）位于线粒体中，它们在绿化过程中积累。相比之下，从根、黄化叶或绿叶中纯化的线粒体内的叶酸在蛋白质基础上是相似的，这表明可能涉及与光和光合作用相关的其他因素。 (C) 2001 年化学工业学会。
The total folate content of various tissues from pea seedlings was determined using a microbiological assay. m the seed the bulk of folate was located in cotyledons, but the embryo, representing only 2% of the total seed fresh weight, had a folate concentration about three times higher. In the presence of sulphanilamide, an inhibitor of folate biosynthesis, the initial folate content supported root elongation during the first 1-2 days. However, further growth of the seedling was not possible and required a de novo synthesis of folate. Following organogenesis, the folate content of young roots and shoots was similar to that in the initial embryo. In contrast, the folate content of young leaves increased rapidly to reach a value two to three times higher than in other tissues after 7 days of growth and remained roughly constant thereafter. The intracellular distribution of folate was estimated in 12-day-old leaves. Mitochondria, the site of folate synthesis, contained approximately 30% of the total cellular folate. The folate level in chloroplasts was about 100 times lower than in mitochondria, representing, on a protein basis, less than 4% of the total pool. We associate the bulk of folate with the cytosol plus nucleus (65-70% of the pool), although mitochondria (less than 5% of the cytoplasmic volume) had the highest concentration. Why there should be more folate in leaves, on a fresh weight basis, than in other tissues is not clear. The folate-dependent enzymes involved in photorespiration (glycine decarboxylase and serine hydroxymethyltransferase) are located in mitochondria where they accumulate during greening. In contrast, the folate within mitochondria purified from either roots, etiolated leaves or green leaves was, on a protein basis, similar, suggesting that other factors related to Light and photosynthesis might be involved. (C) 2001 Society of Chemical Industry.