香椿种子萌发初始阶段物质代谢的研究

Matter metabolism of Toona sinensis seeds at initial germination stage

置香椿种子于(25±1)℃培养箱中培养,通过分析种子含水量、呼吸速率和种胚内含物的变化,探讨香椿种子萌发初始阶段的代谢规律。结果表明:香椿种子中含水量和呼吸速率在萌发初始阶段的变化趋势基本一致,含水量变化分为快速升高、滞缓2个阶段,呼吸速率变化分为快速升高、滞缓和重新迅速升高3个阶段;种胚中的内含物质在培养初27 h降解不明显。可溶性糖含量在培养36 h迅速降低,45 h达到最低(0.51%);淀粉含量于36—45 h短暂回升后迅速降低,培养81 h达最低值(28.01%);蛋白质和粗脂肪比淀粉及可溶性糖动员稍快,在培养27 h后就大幅度下降,是香椿种子首先利用的贮藏物质,蛋白质和粗脂肪分别于培养63 h和54 h时降为最低值(0.32%和20.05%)。可见,香椿种子萌发初始阶段,种胚贮藏物质的降解主要在置床27 h后,但贮藏物质代谢的启动时间略有差异。

With Toona sinensis(A.Juss)Roem seeds incubated at(25±1)℃,through analyzing the change of seed moisture content,respiratory rate and embryonic constituents,seed metabolism at initial germination stage were studied.We found that the change trend of moisture content was almost consistent with that of respiratory rate,rapidly rising first and then stagnated for two phases in moisture content,rapidly rising first and then stagnated,but rapidly rising again in respiratory rate.During early 27 h incubation,embryonic constituents was not degraded obviously.But at 36 h duration,soluble sugar content declined rapidly,with minimum value(0.51%)at 45 h duration.Between 36—45 h duration,starch content briefly rose and then quickly declined again,with minimum value(28.01%)at 81 h duration.Protein and crude fat as seed reserves,were metabolized faster than starch and soluble sugar,with dropping by a large scale after 27 h incubation,with minimum value(0.32%)at 63 h duration in protein,and minimum value(20.05%)at 54 h duration in crude fat.So it was concluded that at initial germination stage,the degradation of embryonic reserves started after 27 h incubation,with initiating time of reserve metabolism different slightly.