低温诱导芹菜种子次生休眠及其调控机制.

[Objectives] The paper aimed to investigate the inhibitory effect of 5 °C low temperature treatment on seed germination of celery and its regulatory mechanism. [Methods] The seeds of Shanghai yellow heart' were treated at 5 and 20 °C to explore the germination, gibberellin(GA) and abscisic acid(ABA) contents, the dynamic changes of key genes expression in metabolic pathways, and the dynamic changes of starch and soluble sugar contents. [Results]5 °C low temperature treatment significantly inhibited the seed germination rate, seedling emergence rate, relative water absorption and embryo growth of celery, while 20 °C treatment could rapidly promote the seed germination. And after the seeds treated at 5 °C for 15 days were transferred to 20 °C (T5-20 treatment), the seeds could quickly recover their germination vitality, which indicated that 5 °C low temperature did not cause irreversible damage to the seeds. The results of seed vitality staining also indicated that low temperature did not cause damage to the embryo structure. Low temperature at 5 °C also markedly inhibited the synthesis of GA during germination, and the expression of related metabolism and downstream genes was also markedly inhibited, while 20°C treatment significantly promoted the synthesis of GA, and the high expression of GA3ox1 gene in seeds treated at 20 °C and T5-20 meant that it might play a key role in the synthesis of GA. ABA content showed a dynamic change in 5 °C treatment, but GA/ABA showed a downward trend in adults. The expression of the ABA degrading gene CYP707A1 had a significant negative correlation with ABA content in the middle and late stages of seed germination 5 °C treatment. In addition, 5 °C also significantly inhibited the sugar metabolism capacity of celery seeds. The starch content of celery seeds treated at 5 °C was significantly higher than that treated at 20 °C, but the soluble sugar content was significantly lower than that treated at 20 °C. [Conclusions] Low temperature at 5 °C induced secondary dormancy of celery seeds. GA/ABA might be an with low temperature. in important signal of celery seeds' response to ambient temperature, and GA3ox1 and CYP707A1 were potential key genes to cope. [ABSTRACT FROM AUTHOR]