聚乙二醇(PEG6000)模拟干旱胁迫抑制矮沙冬青种子的萌发

Inhibition of Seed Germination of Ammmopiptanthus nanus (M. Pop.) Cheng f. under Simulated Drought Stress with Polyethylene Glycol (PEG6000)

本研究以新疆特有濒危保护植物矮沙冬青(Ammmopiptanthus nanus(M.Pop.)Cheng f.)的种子为材料,用不同渗透势浓度的聚乙二醇(PEG6000)模拟干旱胁迫,探讨干旱胁迫对矮沙冬青种子发芽率、平均发芽速度、胚轴和胚根长度及发芽指数、活力指数的影响。结果表明,不同浓度PEG胁迫处理均降低了种子的发芽率,延缓了矮沙冬青种子萌发进程;种子的发芽率、发芽指数和活力指数均随胁迫强度的增加呈明显下降趋势。当-1.20MPa的PEG胁迫处理的种子在试验结束时仍未能萌发,表明-1.20MPa是矮沙冬青种子萌发的临界水势。PEG模拟干旱胁迫中,当PEG处理为-0.2MPa时,虽然最终发芽率与对照一样,但其胚根、胚轴的长度都比对照短,说明矮沙冬青胚根、胚轴的生长比发芽率对干旱胁迫更敏感。干旱胁迫可能是导致矮沙冬青种群天然更新能力弱的原因之一。本研究将为矮沙冬青种质资源的保护和种群的恢复提供科学依据。

In this paper, we have taken the seeds of endangered species A mmmopiptanthus nanus （M. Pop.） Cheng f. as the test material, and studied on the effects of simulated drought stress with different concentration and osmotic potential of polyethylene glycol （PEG6000） on their seminal germination, such as germination capacity, average speed of germination, length of radicle and hypocotyls, germination index and viability index. The results showed that PEG could retard the proceeding of seeds germination ofA mrnmopiptanthus nanus （M.Pop.） Cheng f. and the germination percentage, germination index, and seed viability index were all showed the downtrend obviously with increasing concentration of PEG. The seeds treated with - 1.20 MPa water potential of PEG could not germinate at all after the experiment finished, so we suggested that -1.20 MPa water potential was the threshold for the germination ofA mmmopiptanthus nanus （M.Pop.） Cheng f. seeds. Under the treat condiction of-0.20 MPa water potential of PEG, test material even have a same germination percentage comparing with contrast （CK）, the lengths of radicle and hypocotyl were shorter, it illustrated that the growth of radicle and hypocotyl may be more sensitive to PEG-simulated drought stress than germination percentage. Then drought stress might be a possible cause that inhibited the natural regeneration ofA mmmopiptanthus nanus （M.Pop.） Cheng f.. This paper should be provide a scientific foundation for the protection of species resources and the populations recovery ofA mmmopiptanthus nanus （M. Pop.） Cheng f..