Subdivision of C4-Pathway Species Based on Differing C4 Acid Decarboxylating Systems and Ultrastructural Features
Subdivision of C4-Pathway Species Based on Differing C4 Acid Decarboxylating Systems and Ultrastructural Features
复制标题
DOI：
10.1071/pp9750111
复制
发表时间：
1975
影响因子：
3
通讯作者：
M. Hatch;T. Kagawa;S. Craig
中科院分区：
文献类型：
--
作者：
M. Hatch;T. Kagawa;S. Craig
选择的C4物种进行了调查，以确定它们的C4酸脱羧酶的含量之间的关系，其他几种酶的活动涉及的C4途径，和它们的解剖和超微结构特征。根据它们是否含有高水平的NADP苹果酸酶（EC 1.1.1.40）、磷酸烯醇丙酮酸羧激酶（EC 4.1.1.49）或NAD苹果酸酶（EC 1.1.1.39），所检查的物种明显分为三组。高NADP苹果酸酶活性的发生总是与较高的NADP苹果酸脱氢酶活性相关，而那些以其他两种脱羧酶的高活性区分的物种总是含有高天冬氨酸转氨酶和丙氨酸氨基转移酶活性。这些脱羧酶都位于维管束鞘细胞中。NAD苹果酸酶，但不是磷酸烯醇式丙酮酸羧激酶，与线粒体。光镜和电镜照片显示，这些群体之间的差异就细胞内的位置叶绿体和线粒体在束鞘细胞，线粒体的内容和超微结构。具有高NAD苹果酸酶的物种的趋势是在束鞘细胞中含有最多的线粒体，其嵴膜系统明显最广泛地发达。然而，线粒体呼吸酶活性的三组物种相似。三组C4植物区分其不同的C4酸脱羧系统之间的基本相似性和差异进行了讨论，并提出了可能的光合作用在维管束鞘细胞的反应计划。提出了区分这些群体的命名法。
A selection of C4 species was surveyed to determine the relationship between their content of C4 acid decarboxylating enzymes, the activities of several other enzymes implicated in the C4 pathway, and their anatomical and ultrastructural features. The species examined clearly fell into three groups according to whether they contained high levels of either NADP malic enzyme (EC 1.1.1.40), phosphoenolpyruvate carboxykinase (EC 4.1.1.49) or NAD malic enzyme (EC 1.1 .1.39). The occurrence of high NADP malic enzyme activity was always associated with higher NADP malate dehydrogenase activity, while those species distinguished by high activities of either of the other two decarboxylases invariably contained high aspartate aminotransferase and alanine amino- transferase activities. Each of these decarboxylating enzymes was located in bundle sheath cells. NAD malic enzyme, but not phosphoenolpyruvate carboxykinase, was associated with mitochondria. Light and electron micrographs revealed differences between these groups with respect to the intracellular location of chloroplasts and mitochondria in bundle sheath cells, and the content and ultrastructure of mitochondria. The trend was for species with high NAD malic enzyme to contain the most mitochondria in the bundle sheath cells with apparently the most extensively developed cristae membrane systems. However, mitochondrial respiratory enzyme activities were similar for the three groups of species. The basic similarities and differences between the three groups of C4 plants distinguished by their differing C4 acid decarboxylating systems are discussed, and schemes for the probable photosynthetic reactions in bundle sheath cells are presented. A nomenclature to distinguish between these groups is proposed.