芸薹属作物在发根农杆菌介导下的最适转化条件

Optimal Conditions for Transformation of Brassica Crops with Agrobocterium rhizogenes

光照和温度对甘蓝、花椰菜和油菜在发根农杆菌介导下的离体遗传转化具有很 大的影响。光下培养的下胚轴切段比暗中培养的下轴胚切段诱发出较多的转化根,而暗中培 养的毛状根比光下培养的毛状根具有较强的侧根分生和伸长生长能力。在25℃的温度条件 下,甘蓝切段的转化频率最高,然而在28℃的温度条件下,甘蓝毛状根的相对生长速度最 高。在5.2～6.7的范围内,pH值对毛状根的生长速率无明显影响。根据环境条件的不同反 应,可以将转化过程分为两个阶段:根诱导阶段和根生长阶段。

______ Light and temperature have had an important effect on in vitrogenetic transformation of cabbage, cauliflower and oilseed rape by Afrhizoge-nes. In the light more transformed roots were induced on hypocotyl segments than in dark.In contrast to this, the hairy root initials in the dark produced more, longer lateral roots and larger hairy root lines than those in the Light.With cabbage segments,the highest transformation frequency was attained at 25 whereas the highest relative growth rate of hairy roots was reached at 28.Growth rate of hairy roots was not affected by pH in the range 5.2.-6.7 but some outgrowth of A,rhizogenes occurred when pH was above 6.2. This pattern of environmental responses makes it possible to divide such transformation procedures into two stages; a root induction stage and a root growth stage.