Enhancement of Somatic Embryogenesis by a Novel Control Method of Phytohormone

本研究从工程角度探讨了体细胞胚胎发生技术对植株再生效率的影响。1）核黄素对体细胞胚胎发生的影响核黄素对2，4-D（一种人工合成的生长素）的降解率与光照强度密切相关。FAD和EMN对2，4-D的降解也有催化作用，而2，4-D降解的主要产物光色素对2，4-D的降解没有催化作用。B）核黄素的加入提高了胡萝卜细胞和培养基中2，4-D的降解速率，也提高了再生效率。c）核黄素固定化珠（RF-珠粒）合成，其中疏水性烷基链作为生长素分解的接头。d）具有RF-珠粒的胡萝卜细胞培养物增加了体细胞胚形成的效率，然而过量的珠粒抑制了再生可能是因为通过2，4-D降解。c）提出了一种新的带有生长素降解容器的培养体系，以实现有效的体细胞胚发生。2）气相组成分析和气体交换方法a）研究了胡萝卜细胞培养瓶顶空气体组分对体细胞冷冻的影响。B）在水稻愈伤组织悬浮培养液的顶空中，检测到少量的乙醇、乙醛等物质，可能是水稻胚状体发生的抑制因子。然而，在顶空气体中没有观察到任何促进胚胎发生的物质。

In this research, somatic embryogenesis was investigated for the enhanced regeneration efficiency from the engineering viewpoints.1) Effects of riboflavin (RF) addition in the culture systema) Decomposition rate of 2,4-D, a synthetic auxin, by riboflavin depended greatly on light irradiation intensity. FAD and EMN also showed the catalytic activity for the 2,4-D degradation, but lumichrome, the main product of 2,4-D decomposition, cannot.b) Riboflavin addition into carrot cells suspension culture increased the decrease rate of 2,4-D in the cells and the medium, also enhanced the regeneration efficiency.c) Riboflavin immobilized beads (RF-beads) were synthesized with a hydrophobic alkyl chain as a linker for the auxin decomposition.d) The carrot cell culture with RF-beads increased the efficiency of somatic embryo formation, however the excess amount of the beads inhibited the regeneration probably because the damage to the cells by activated oxygen generated through the 2,4-D degradation.c) A novel culture system with an auxin degradation vessel is proposed for the effective somatic embryogenesis.2) Analysis of gas-phase composition and gas-exchanging methoda) Effects of gas components in flask headspace of carrot cell cultures were investigated for somatic cmryogcnesis. Inhibition of ethylene gas and the suppressive effect of carbon dioxide gas on it were suggested.b) In the headspace of rice callus suspension culture, a small amount of ethanol and acetaldehyde etc. was detected, which could be an inhibitory factor for embryogenesis. However, there could not be observed any substances in the headspace gas that enhance embyogenesis.