水势介导的不同胁迫对虎尾草种子发芽的影响

Effect of different types of water potential mediated soil stress on seed germination of Chloris virgata

虎尾草(Chloris virgata)是我国北方地区广泛分布的优质牧草,对东北地区盐碱地改良与恢复起着至关重要的作用。用NaCl,NaHCO3和PEG分别模拟土壤的盐、碱和干旱条件以明确基于相同水势的不同胁迫特征对虎尾草种子发芽的影响。结果表明,在各胁迫处理下,随着水势的降低,虎尾草种子的发芽率、发芽速率以及芽长与根长均不断下降,且碱胁迫下下降幅度最大。盐胁迫处理下,虎尾草种子复萌率在-1.2Mpa最高,干旱胁迫处理中未发芽的种子80%以上也可以继续萌发,但在此水势的碱胁迫中未发芽的虎尾草种子均难以复萌。研究结果表明,盐、碱和干旱胁迫对于虎尾草种子的发芽有着不同的影响,由于高pH作用,碱胁迫对虎尾草发芽的抑制作用强于盐胁迫与干旱胁迫。

Chloris virgatais considered as a useful grass species for grassland restoration in Northern China.The effect of salinity,alkalinity and drought stresses simulated with NaCl,NaHCO3 and PEG solutions on seed germination and seedling growth was studied under same water potential conditions.And the water potentials were-0.2,-0.4,-0.8and-1.2 MPa.Results showed that the seed germination percentage,germination rate,root length and bud length gradually decreased along with the decrease of water potential.Recover percentage in salinity treatment reached the highest at-1.2MPa,and over 80% of seeds germinated at this water potential after removing drought stress.But it was hard to recover under the same water potential of alkali stress.Salinity,alkalinity and drought stresses had different impacts on seed germination.Due to high pH,the inhibitory effect of alkali stress was stronger than salinity and drought stresses.