盐旱耦合胁迫对费尔干猪毛菜种子萌发及其幼苗生长的影响

本研究采用双因素组合实验,探讨盐(NaCl)、干旱(PEG 6000)对费尔干猪毛菜(Salsola ferganica)种子萌发和幼苗生长的影响。结果显示:①费尔干猪毛菜种子萌发能耐受较高浓度NaCl和PEG胁迫。低浓度NaCl或PEG胁迫下,费尔干猪毛菜去翅种子和具翅种子萌发率与对照无显著差异,高浓度NaCl或PEG处理下,去翅种子萌发率35%以上,显示较强的耐盐、耐旱性;盐旱耦合处理下,不同低浓度PEG能够显著缓解中浓度NaCl对种子萌发的抑制作用。②随NaCl浓度升高,具翅种子恢复萌发率逐渐上升,而去翅种子则维持较低水平;随着PEG浓度的升高,2种种子恢复萌发能力显著降低;盐旱耦合处理下2种种子的恢复萌发率与NaCl胁迫具有相同趋势。③NaCl或PEG对去翅种子幼苗的影响比具翅种子强,特别是PEG处理;随NaCl或PEG浓度升高,2种种子幼苗的株高和根长均降低;盐旱耦合处理下低浓度NaCl对去翅种子幼苗的影响比具翅种子小(除了100 mmol·L^-1NaCl+25 g·L^-1PEG处理),中浓度NaCl对去翅种子幼苗的影响比具翅种子强,高浓度NaCl处理下随PEG浓度升高,2种种子幼苗的株高和根长均降低。以上结果显示,费尔干猪毛菜在萌发期和幼苗期具有较强的耐盐耐旱性,盐旱耦合在一定程度上能够缓解盐离子毒害效应,这对其度过早期恶劣环境具有重要的生态学意义;果翅对种子在胁迫下进入次级休眠,从而补充土壤种子库起到重要作用。

Effect of Salt Coupled with Drought Stress on Seed Germination and Seedling Growth of Salsola ferganica

In this study,the effects of different stress conditions,e. g.,salt (NaCl),drought (PEG 6000) or salt coupled with drought,on seed germination (SG) and seedling growth (SGr) of Salsola ferganica were researched. Results showed that:① SG of S. ferganica could tolerate relatively high NaCl and PEG concentrations. There was no effect of low NaCl and PEG concentrations on SG;at higher concentration,however,SG was significantly decreased but its percentage still exceeded 35%,which suggested that S. ferganica was salt-or drought-tolerant. Under salt stress coupled with drought stress,the inhibition of seed germination was significantly relieved by increasing the PEG concentration under the low and medium concentration of NaCl.② Under NaCl stress,the recovery rate of winged perianth (WWP) seeds was increased with increasing NaCl concentration,while that of dewing perianth (NWP) seeds was remained at low level. With increasing the PEG concentration,however,the recovery rates of both WWP and NWP seeds were significantly decreased. The recovery of germination of WWP and NWP seeds under salt coupled with drought stress was similar as that under NaCl stress.③ The effect of NaCl or PEG treatment on the growth of the seedlings from NWP seeds of S. ferganica was stronger than that from WWP seeds. With increasing the NaCl or PEG concentration,the growth of plant height and root length of seedlings from WWP and NWP were inhibited. The growth of S. ferganica seedlings Under salt stress coupled with drought stress,the effect of low NaCl concentration on the growth of the WWP seedlings was less than that of NWP seeds (except for 100 mmol ·L^-1 NaCl + 25 g·L^-1 PEG). The effect of NaCl concentration on the seedlings of NWP seeds was stronger than that of WWP seeds. With increasing the PEG concentration at high NaCl level,the growth of plant height and root length of seedlings from WWP and NWP were inhibited. In conclusion,S. ferganica was much more tolerant to salt and drought in seed germination and seedling growth. Salt stress coupled with drought stress could relieve salt ion toxicity to some extent,which has important ecological significance for S. ferganica to survive the early harsh environment. Moreover,the fruit wing plays an important role in puting the seed to dormancy under stress and then replenishing the soil seed bank.