成年型桂夏橙茎段组织培养中的脱落现象及其生理原因初探

成年型桂夏橙茎段组织培养中的脱落现象与营养水平、激素水平以及外植体的生理发育状态有关。当脱落发生时,培养体的总糖及可溶性蛋白的含量降低,但还原糖含量升高。同时,内源激素水平发生明显变化:培养两周后,脱落将出现之前,内源吲哚乙酸(IAA)含量快速下降,内源脱落酸(ABA)含量与幼年型材料相比,由起始的3.5倍升高到约15倍。培养30d 脱落出现后,内源细胞分裂素 iPA 等价物iPA(eq)]的含量与脱落酸的比值iPA(eq)/ABA]特别高。这种脱落现象以秋梢茎段为外植体时最为严重,而春梢最轻。

STUDY ON ABSCISSION AND ITS PHYSIOLOGICAL REASON IN MATURE CITRUS MATS UDAIDAI HAYATA STEM TISSUE CULTURE

The phenomenon of abscission during the course of culturing mature Citrus matsudaidai Hayata stem sections was closely related to hormone balance,nutritive material levels and physiological development status of explants.When abscission occurred,total sugar and soluble protein were decreased,but reducing sugar was increased.At the same time,endogenous hormone levels varied obviously.After two weeks of culturing when abscission was going to occur,the endogenous IAA content of mature explant was rapidly decreased.However,the endogenous ABA content of mature explant was about 15 times higher than,that of juvenile one,in contrast to only 3.5 times at the beginning of the culture. At the 30th day of culturing,after abscission occurred,endogenous iPA(eq)/ABA ratio was very high.This phenomenon of abscission became more distinct when explants were cut from sprouting shoots in autumn than from those in spring.