MGBG对苜蓿愈伤组织生长、体细胞胚胎诱导及其乙烯生物合成的影响

EFFECT OF MGBG ON GROWTH OF THE CALLUS TISSUE,INDUCTION OF SOMATIC EMBRYOGENESIS OF ALFALFA AND THEIR ETHYLENE BIOSYNTHESIS

在苜蓿（ＭｅｄｉｃａｇｏｓａｔｉｖａＬ．）愈伤组织继代之初加入不同浓度的甲基乙二醛双（脒腙）（ＭＧＢＧ）（０．５，１，２ｍｍｏｌ／Ｌ），可不同程度地抑制愈伤组织及其后体胚诱导悬浮培养物的生长和体胚形成；若在体胚诱导阶段加入，则上述的抑制作用更为强烈。ＭＧＢＧ不但促进愈伤组织乙烯释放量、内源ＡＣＣ（１氨基环丙烷１羧酸）水平和ＡＣＣ合成酶活性，也促进体胚诱导悬浮培养物的ＡＣＣ水平及ＡＣＣ合成酶的活性，但降低体胚诱导悬浮培养物的ＭＡＣＣ（丙二酰ＡＣＣ）水平。ＭＧＢＧ对体胚诱导和培养物的生长的抑制作用与其上述的对ＡＣＣ和乙烯生成促进作用及降低ＡＣＣ转化成ＭＡＣＣ的效应有关。

MGBG [methylglyoxal bis(guanylhydrazone)], when added to the initial of callus subculture, promoted ethylene production in callus grawn in B5h medium, and enhanced the ACC (1aminocyclopropane1carboxylic acid) level and the ACC synthase activity both in the callus grown in B5h medium, and in the suspension cultures in B5g liquid medium for induction of somatic embryogenesis. However, MGBG reduced the malonylACC (MACC) level of the suspension tissues. The treatments of MGBG caused growth of the cultured tissues and induction efficiency of somatic embryogenesis to reduce. Moreover, the effects of MGBG was enhanced when it was added at induction medium of somatic embryogenesis. It could be concluded that this inhibitory effect of MGBG could be due to its promotion of ethylene, ACC levels and ACC synthase activity which has shown to inhibit somatic embryogenesis. The reduction of MACC level could be also involved in the MGBG effect on induction of the embryogenesis.