低溫馴化對綠豆（Vigna radiata L.）幼苗之生理與生化改變的影響

Abstract

本論文以低溫敏感性植物-綠豆（Vigna radiata L., VC3890A）為實驗材料，取五天大的綠豆幼苗，在4℃下處理兩天，即可造成不可逆性的傷害。將綠豆幼苗予以10℃的馴化處理，則在4℃的環境下，可視性傷害（visible injury）能獲得明顯改善。和未馴化植株做比較，經過低溫馴化處理的植株，在生理及生化代謝方面亦有差異，包括細胞膜系完整度提高、光合作用及乙烯合成能力增強、陽離子（K＋、Ca2＋、Mg2＋）濃度改變、可溶性醣類之累積、極性胺基酸的增加、可溶性蛋白質含量提高及蛋白質合成能力增強等。這些變化都是為了減輕低溫壓迫（4℃）所造成的傷害，以增加植株生存能力的因應之道。 以電泳分析來比較馴化及未馴化植株蛋白質合成類型與量的變化，發現馴化植物會合成三群新的蛋白質，分子量分別為36、21.5及19KD，這三群蛋白質在10℃，8小時之內便已合成，且在常溫下，除了36KD蛋白質外，在24小時內多能迅速分解。 控制植株根部溫度，以研究根溫在寒害中扮演的角色，由結果得知低根溫會造成植株失水，礦物營養吸收不良，導致生理代謝作用不正常但仍能合成低溫馴化蛋白質，由電泳分析結果，得知低溫馴化蛋白質的誘導?生可能是植株地上部分對低溫環境變化所產生的反應。

Exposure of 5-day-old mung bean (Vigna radiata L.) seedlings (chilling-sensitive plants) to a chilling treatment of 4℃ for 2 days induced an irreversible chilling injury. Pretreatment of mung bean seedlings with 10℃ for the cold-acclimation process resulted in protection from the injury caused by a treatment at 4℃. There were many differences in physiological and biochemical changes between the acclimated and nonacclimated plants, such as cell leakage, photosynthetic activity, protein synthesis, ethylene produuction and concentrations of cations (K+, Ca2+, Mg2+), soluble sugars and the free amino acids. All these alterations produced seems resulted to release from chilling injury, and improve the survivality of chilling-sensitive plants. Changes of protein synthetic patterns during cold acclimation of mung bean seedlings were analyzed by acrylamide gel electrophoresis. Three newly synthesized proteins (acclimated proteins) with the molecular weight of 36, 21.5 and 19 KD, respectively were found by acclimation temperature of 10℃. They were induced within 8 hours and synthesis declined after one day at room temperature except 36 KD protein. When only the shoots of the seedlings were exposed to 4℃ and the lest of the seedlings were kept at 28℃ for two days, no noticeable differences were found compared to the whole seedlings were kept at 28℃. The protein synthetic patterns obtained from the shoots were also not affected by the exposure of the roots of the seedlings to 28℃.