Cytokinin Biosynthesis and Metabolism
Cytokinin Biosynthesis and Metabolism
复制标题
DOI：
10.1007/978-94-009-3585-3_5
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
B. Mcgaw
中科院分区：
文献类型：
--
作者：
B. Mcgaw
植物细胞分裂受化学控制的观点并不新鲜，事实上，它可以追溯到上个世纪，但正是哈伯兰特在1913年（31）为这一概念提供了第一个实验证据。他指出，韧皮部扩散物可以刺激薄壁马铃薯块茎细胞恢复到分生状态。然而，未确定这些扩散液中活性物质的鉴别。在20世纪40年代末和50年代，Folke Skoog及其同事开始了一系列对烟草茎髓组织培养物营养需求的研究。在含有生长素的成分培养基上，髓组织细胞扩大，但未能分裂。然而，在添加几种复杂和未定义的材料时，恢复了“正常”细胞分裂，最值得注意的是：椰奶，血管组织提取物，高压灭菌的DNA和酵母提取物（58）。1959年（57），从高压灭菌的鲱鱼精子DNA中纯化出6-（糠氨基）嘌呤（图1），从而确定了第一种活性细胞分裂促进剂（或现在已知的细胞分裂素）。该化合物虽然是最具生物活性的细胞分裂素之一（在烟草愈伤组织生长生物测定中记录的活性水平为10- 9 M（72）），但它是加热DNA的人工重排产物，在植物组织中未发现。第一个图1。6-（糠基氨基）天然存在的细胞分裂素在1963年由Letham（40）从玉米的未成熟籽粒中纯化为嘌呤或激动素，并鉴定为6-（4-羟基-3-甲基丁基-反式-2-烯基氨基）嘌呤，更通常称为玉米素。实际上，所有天然存在的细胞分裂素似乎都是嘌呤衍生物（图2），带有一个支链的5个碳原子的N6取代基（尽管这一取代基可以通过共轭作用延长）。细胞分裂素被定义为（80）”与生长素结合刺激植物细胞分裂并与生长素相互作用决定细胞分化方向的物质”。该术语现在被松散地用于涵盖所有具有嘌呤结构的嘌呤化合物。
The view that plant cell division is chemically controlled is not new, indeed it can be traced back to the last century, but it was Haberlandt in 1913 (31) who provided the first experimental evidence for this concept. He showed that phloem diffusates could stimulate parenchymatous potato tuber cells to revert to a meristematic state. However the identity of the active substance/s in these diffusates was not established. In the late 1940s and 1950s Folke Skoog and co-workers began a series of investigations into the nutritional requirements of tissue cultures derived from tobacco stem pith. On defined media in the presence of auxin the pith tissue cells enlarged, but failed to divide.'Normal'cell division was restored, however, on the addition of several complex and undefmed materials, most notably: coconut milk, vascular tissue extracts, autoclaved DNA and yeast extracts (58). The conclusive identification of the first active cell division promotor (or cytokinin as they are now known) was achieved in 1959 (57) when 6-(furfurylamino) purine (Fig. 1) was purified from autoclaved herring sperm DNA. This compound, though one of the most biologically active cytokinins (with activity recorded at levels of 10-9M in tobacco callus growth bioassays (72» is an artefactual rearrangement product of heated DNA and is not found in plant tissues. The first Fig. 1. 6-(furfurylamino) naturally occurring cytokinin was purified in 1963 purine or kinetin by Letham (40) from immature kernels of Zea mays and identified as 6-(4-hydroxy-3-methylbut-trans-2-enylamino) purine, more commonly known as zeatin. Virtually all the naturally occurring cytokinins appear to be purine derivatives (Fig. 2) with a branched 5 carbon N6 substituent (though this may be lengthened by conjugation).Cytokinins have been defined (80)" as substances which, in combination with auxin, stimulate cell division in plants and which interact with auxin in determining the direction which differentiation of cells takes". The term is now loosely used to cover all purine compounds that possess the