J Integr Plant Biol. ›› 2003, Vol. 45 ›› Issue (6): 705-711.

• Research Articles • Previous Articles     Next Articles

Fluctuations of Endogenous Hormones in Isolated Rice Embryos During Embryogenesis and Early Stages of Germination

YANG Jun, ZHAO Jie, ZHOU Xie, YANG Hong-Yuan   


Fluctuations of levels of several endogenous plant hormones in isolated rice (Oryza sativa ssp. japonica) embryos during early and mid-embryogenesis and early stages of germination were studied by enzyme-linked immunosorbent assay (ELISA). Embryos were collected at different days after pollination (DAP) and different days after imbibition (DAI) of mature seeds. The contents of gibberellin 1 (GA1), abscisic acid (ABA), isopentenyladenine and isopentenyladenosine (iPAs), zeatin and zeatin riboside (ZRs) were immunochemically assayed. The GA1 level was the highest among all hormones tested. The variations of GA1 levels were opposite with the ABA levels, with some exceptions. During early and mid_embryogenesis, the levels of GA1 and ABA were the highest at 4 DAP. From 8 to 18 DAP, GA1 level declined, whereas the ABA level increased. During germination, GA1 level increased at 2 DAI whereas simultaneously the ABA content decreased. The highest ratio of GA1/ABA was observed at 2 DAI. The levels of iPAs and ZRs were maxima in the embryos at 4 DAP, decreased to a very low level and maintained constant thereafter. Our results provide further evidence that GA1 plays an important role in the early stages of embryo development and germination. The balance between GA1 and ABA, rather than their absolute contents, controls these processes throughout the development, whereas iPAs and ZRs may play important roles in early embryogenesis. The use of isolated embryos as starting material avoids the usual interferences with other tissues such as the endosperm. In addition, this is the first report dealing with the hormonal balance of early-embryos in rice.  

杨 军  赵 洁  周 燮  杨弘远
(1.  武汉大学植物发育生物学教育部重点实验室,武汉430072; 南京农业大学农学院,南京210095)

摘要: 以酶联免疫吸附检测技术分析了水稻(Oryza sativa ssp. japonica)分离胚不同发育时期及萌发早期的内源激素含量的动态变化.GA1含量是所测激素中含量最高的.GA1的变化趋势基本上与ABA相反.花后4 d的胚中GA1和ABA的含量最高;花后8 d到18 d,GA1的含量下降,而ABA含量增加.在早期萌发过程中,种子吸涨后2 d的胚中GA1含量迅速上升,而ABA下降.GA1/ABA的最高比值也出现在吸涨后2 d的胚中.iPAs和ZRs的最高含量也出现在开花后4 d的胚中,但随后含量均下降到相当低的水平,并几乎没有变化.研究结果进一步证实了GA1在早期胚胎发生和萌发过程中起重要的作用;推测iPAs和ZRs可能仅在胚胎发生的早期起作用;GA1与ABA含量之间的相对平衡控制着胚胎发育的过程.用分离胚作为测试材料可以避免胚乳等其他组织成分的干扰,从而比较准确地反映了胚的内源激素变化.此外,本研究是首次用4 d的水稻幼胚作为激素含量测定的起始材料.

关键词: 植物激素;胚胎发生;萌发;分离胚;水稻

通讯作者。E-mail: <hyyang 2@ whu.edu.cn>。


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