文冠果幼苗对盐胁迫的生长策略响应和耐盐性阈值研究

为探讨盐胁迫对文冠果幼苗生长影响,对不同浓度配比(0%、0.2%、0.5%、0.8%)盐分(Na Cl:Na2SO4=9:1)胁迫处理下一年生文冠果幼苗的存活率、苗高、地径、生物量、根冠比、茎叶比进行测定。结果表明:随着盐浓度的增加,幼苗生长指标呈现逐渐下降趋势,生长明显受到抑制,在轻度盐胁迫(0.2%)处理下,地径、根系干重、根冠比高于对照;而中度(0.5%)和重度(0.8%)胁迫处理幼苗各生长指标均显著低于对照。对照、轻度和中度胁迫幼苗存活率为100%,重度胁迫幼苗存活率下降明显。试验表明在盐胁迫条件下,轻度胁迫对幼苗存活和抑制作用弱于中度和重度胁迫,当幼苗受轻度胁迫后通过增粗茎干,增加根系的生长发育,来维持幼苗的正常生长;将总生物量抑制率为50%的盐浓度定义为该幼苗的耐盐性阈值,文冠果幼苗的耐受阈值的盐浓度为0.8%。

Growth Strategy Response to Salt Stress and Salt Tolerance Threshold of Xanthocera ssorbifolia Bunge Seedlings

In order to investigate the effects of salt stress on seedling growth of Xanthocera ssorbifolia Bunge, the survival rate, seedling height, ground diameter, biomass, root-shoot ratio and stem-leaf ratio of annual Xanthocera ssorbifolia Bunge seedlings were analyzed under different concentrations (0%, 0.2%, 0.5%, 0.8%) of salt (NaCl:Na2SO4=9:1) stress treatment. The results showed that seedling growth indicators presented a gradual downward trend with the increase of salt concentration, the growth was inhibited obviously, ground diameter, root dry weight, root-shoot ratio were higher than that of control under mild salt stress (0.2%); seedling growth indexes were significantly lower than that of control under moderate (0.5%) and severe (0.8%) salt stress. The seedling survival rate reached 100% under control, mild and moderate salt stress, the seedling survival rate decreased significantly under severe salt stress. Tests showed that under salt stress, seedling survival and inhibiting effect under control and mild salt stress were weaker than that of moderate and severe salt stress. The seedling could maintain normal growth by thickening the stem, increasing root growth under mild salt stress; 50% of the total biomass was defined as the threshold of salt-tolerance of seedlings, and the threshold of salt-tolerance of Xanthocera ssorbifolia Bunge seedlings was 0.8%.