体细胞胚发生的生化基础

The biochemical base of somatic embryogenesis

在胚性细胞分化和分裂过程中ＡＴＰ酶活性和分布的动态变化表明，这些胚性细胞进行着旺盛的主动物质吸收和活跃的新陈代谢过程。在多种植物的体细胞胚发生中过氧化物酶的活性与同工酶的种类都高于对照，而且在大麦中发现过氧化物酶、酯酶和酸性磷酸酶同工酶的结合应用可以作为体细胞胚发生的标志酶。胚性愈伤组织中可溶性蛋白质含量与组分远高于或多于非胚性愈伤组织。大多数材料中都存在４５ｋＤ～５５ｋＤ的胚胎发生特异性蛋白质组分。而且在体细胞胚发生中蛋白质和核酸代谢动态呈规律性变化，首先是ＲＮＡ合成速率增加，继而是蛋白质的迅速合成，并在胚性细胞分化和发育过程中一直保持相对较高水平；其中ｍＲＮＡ种类丰富，不同发育时期ｍＲＮＡ种类不同，因此转译形成多种蛋白质。ＤＮＡ的代谢相对较稳定；但在胚性细胞系中ＤＮＡ合成量仍高于非胚性细胞系。加入蛋白质或核酸合成抑制剂，不仅抑制了蛋白质和核酸的合成，同时也抑制了体细胞胚的发生与发育，而且抑制剂加入时间愈早，影响愈严重。由此表明，蛋白质与核酸的合成为体细胞胚的分化和发育奠定了分子基础。

The dynamic changes of ATPase activity and distribution in embryogenic cells differentiation and division show that these embryogenic cells are in a state of active material absorption and active metabolism. The activity of peroxidase and the type of its isoenzyme are higher in various plant somatic embryogenesis than in the control. The peroxidase, the esterase in combination with the acid phosphatase can regard as the enzyme marker of somatic embryogenesis in barley. The content and the element of soluble protein in embryogenic calli are higher and more than in non-embryogenic calli. There are embryogenesis-specific proteins (45-55kD) in various materials. The metabolic dynamic state of proteins and nucleic acid appears a regular change in somatic embryogenesis. At first, the rate of RNA synthesis quickened, then proteins are synthesized rapidly and kept in a relative higher level during embryogenic cell differentiation and development. At the same time, there are rich various mRNAs. There are differential types of mRNAs in different stages of development. So it can synthesize various proteins. The metabolism of DNA is relative steady. However, the content of DNA in embryogenic cell line is higher than in non-embryogenic cell line. Adding inhibitors of proteins or nucleic acid synthesis inhibits not only the protein or nucleic acid synthesis but also somatic embryogenesis and development. The earlier inhibitors adding, the more serious it affects. This result shows that the synthesis of proteins and nucleic acid lays a molecular foundation for the differentiation and development of somatic embryos.