多花水仙种球膨大期对乙烯的响应研究

Response of Narcissus tazetta to Ehtylene During Bulb Swelling Phase

为探讨乙烯在水仙鳞茎膨大过程中的作用以及种球对乙烯信号的响应,本试验以多花水仙种球膨大期的鳞片和内芽为供试材料,研究种球的生长与乙烯释放量和NtERFs基因表达之间的关系。结果表明,多花水仙种球在3—5月间种球重量持续增加,为种球的膨大期。鳞片的乙烯释放量在5月中旬显著升高,内芽的乙烯释放量显著高于鳞片,在4月下旬出现释放高峰;内芽释放的乙烯可能与种球的膨大有关,且能够诱导鳞片中乙烯的释放,鳞片乙烯的释放可能会引起地上部叶片的黄化。实时荧光定量PCR结果表明,NtERF1、NtERF4和NtERF118的表达趋势与鳞片乙烯的释放量一致,可能参与了鳞片乙烯信号的响应,NtERF1可能是关键的响应因子。NtERF2、NtERF3、NtERF4和NtERF26基因则可能参与内芽乙烯信号的响应,NtERF2基因可能是内芽响应乙烯信号的主要因子,同时也参与了鳞片对内芽释放的乙烯信号的响应。本研究表明水仙种球在生长期能够响应乙烯信号,而乙烯的释放受到NtERFs的反馈调节。本研究结果为进一步研究水仙种球营养生长期乙烯的作用及其信号传导提供了研究基础。

In order to explore the role of ethylene and the response to ethylene signal of narcissus bulbs during bulb swelling phase, the ethylene amount and NtERFs genes expression in scales and inner buds of narcissus bulbs were detected. The relationships among bulb development, ethylene content and the expression of NtERFs genes were discussed. The results showed that the weight of bulb continually increased from March to May, which indicated that this period was swelling phase of bulbs. Ethylene amount released from scales increased sharply in mid-May. The ethylene released from inner bud was significantly higher than that from scales, and the peak appeared in late April. These results suggest that the ethylene released from inner bud has a bearing on bulb expansion and can induce the releasing of ethylene from scales. The ethylene from scales could lead to leaf chlorosis. The expression profiles of NtERF1, NtERF4 and NtERF118 were consistent with the ethylene releasing pattern of scales, those 3 genes may be involved in ethylene signaling in scales, and NtERF1 could be a key response factor. NtERF2, NtERF3, NtERF4 and NtERF26 might participate in ethylene signaling response in inner bud, and NtERF2 gene was a primary ethylene response factor of inner bud, in addition, the NtERF2 gene from scales could involve in the signaling response to the ethylene released from inner bud. Hence, these results implied the feedback regulation among vegetative growth, ethylene releasing and NtERFs expression in narcissus bulbs. The results of this study provided a basis for further study on the role of ethylene and its signal transduction in the vegetative growth of narcissus bulbs.