大白菜下胚轴不定芽再生过程中内源激素和多胺含量的变化

Changes of endogenous hormone and polyamine contents during in vitro adventitious shoot regeneration from hypocotyI explants of Chinese cabbage

研究了大白菜[Brassica campestris ssp．pekinensis(L．)Olsson]下胚轴不定芽再生过程中内源激素和多胺含量的动态变化。结果表明,芽原基出现以前(接种后0～8d)外植体内源玉米素核苷(ZRs)和脱落酸(ABA)含量上升,而吲哚乙酸(IAA)含量下降；不定芽出现(接种后8d)后变化趋势相反；ABA／IAA值和ZRs／IAA值在培养初期(接种0～8d)增大,不定芽出现以后逐渐减小。不定芽分化过程中外植体内源腐胺(Put)、精胺(Spm)和亚精胺(Spd)含量都表现为先上升后下降,均在培养第8d时达到峰值；Spm／Put值和Spd／Put值的变化趋势也与此相似。说明大白菜下胚轴不定芽的再生与内源激素和多胺含量及平衡有密切关系。

Dynamic changes of endogenous hormone and polyamine contents were investigated during in vitro shoot regeneration from hypocotyl explants of Chinese cabbage [Brassica campestris ssp. pekinensis （L.） Olsson]. The results were as follows. Before shoot primordia occurred （0 to 8 days after inoculation）, endogenous zeatin ribosides （ZRs） and abscisic acid （ABA） contents increased, while indole-3-acetic acid （IAA） content decreased. After shoot promordia occurred （on the 8th day of inoculation）, the contrary changing patterns of ZRs, ABA and IAA contents were observed. At the early stage of culture （0 to 8 days after inoculation）, ABA/IAA and ZRs/IAA ratios increased, then gradually decreased after adventitious shoots occurred. Endogenous putrescine （Put）, spermine （Spm） and spermidine （Spd） contents increased at the early stage and then gradually declined during the culture course, these indexes reached their peaks on the 8th day of culture. Similar changing patterns were also observed in the ratios of Spm/Put and Spd/Put. The results indicated that endogenous hormone and polyamine contents and their balance were closely associated with the in vitro adventitious shoots regeneration from hypoeotyl explants of Chinese cabbage.