多胺对宁夏枸杞愈伤组织器官发生和体细胞胚发生的影响

EFFECTS OF POLYAMINES ON ORGANOGENESIS AND SOMATIC EMBRYOGENESIS OF LYCIUM BARB ARUM CALLI

利用已建立的宁夏枸杞(Lycium barbarum L.)愈伤组织器官发生和体细胞胚发生体系,对多胺在其离体形态发生中的作用进行研究。通过检测内源多胺含量发现,在所研究的三种多胺中,Put是器官发生途径的主要多胺,而在体细胞胚发生途径Spd含量占优势。Put含量变化在两条途径中相似:在愈伤组织分化的早期迅速积累不久又下降,随着芽原基和球形胚的形成含量又进一步上升。器官发生中Spd最高含量仅在培养的第一天出现;而从诱导愈伤组织发生体细胞胚的第一天后,Spd含量才开始上升,到第十天时达到最高值。三种外源多胺的添加均能有效地促进两条离体分化途径的形态建成:Spd(100μmol/L)能显著增加不定芽数,而体细胞胚发生中Spd(10 μmol/L)或Put(100 μmol/L)的单独处理能最好地促进体细胞胚形成和进一步发育成苗;尽管Spm在离体形态发生中含量较低,但添加外源Spm也促进了不定芽形成和体细胞胚形成然后成苗。多胺生物合成抑制剂CHA处理阻碍不定芽形成和体细胞胚的进一步发育;但是MGBG对器官发生途径中的形态建成没有影响,却降低体细胞胚的发生频率及再生苗数。添加Spd(50μmol/L)能部分逆转CHA、MGBG的抑制效应。以上结果表明,多胺对宁夏枸杞器官发生和体细胞胚发生途径的离体形态建成有一定影响。

Levels of three endogenous free polyamines (PAs), Put, Spd and Spm, were detected during organogenesis and somatic embryogenesis (SE) of Lycium barahrum (L. ) calli. The predominant forms of PAs in organogenesis and SE were found to be Put and Spd, respectively. In both developmental pathways, the changes of Put content were very similar, i.e., it accumulated quickly in the initial stages of calli differentiation and then decreased; with the further morphogenesis, increase in Put level was also observed. The highest level of Spd was obtained at day 1 of calli organogenesis; while, after 1 day of culture for calli SE, Spd level began to increase and reached a maximum at day 10. The treatments with exogenous PAs had positive effects on both organogenesis and SE, especially those of Spd on organogenesis and SE and Put on SE. However, Put showed no effects on adventitious bud formation. CHA, which inhibits the activity of Spd synthetase, prevented both adventitious bud formation and further development of somatic embryo into plantlet. Although MG-BG, a specific inhibitor of S-adenosyl methionine decar-boxylases, had little effects on organogenesis, it reduced the number of somatic embryo and the plantlets subsequently regenerated. Such inhibitions could be reversed by Spd (50 μmol/L). These results from organogenesis and SE of the same specie indicate that PAs influenced these two in vitro morphogenesis pathways.