盐分胁迫对杨树苗期生长和土壤酶活性的影响

通过盐分胁迫下杨树2个无性系的盆栽试验，发现盐分对苗木的生长有一定的抑制作用.随着盐分浓度的提高，苗高、地上与地下部分生物量都呈下降趋势；当盐分浓度为0.2%、0.4%、0.6% 和0.8%时，P₁、P₂的新稍生长量分别比对照下降23.24%、48.56%、70.76%、83.33%和71.77%、83.25%、86.28%、91.39%；P₂地上生物量分别比对照下降72.44%、82.92%、92.82%和94.41%.回归分析发现，盐分浓度与叶片叶绿素含量之间存在线性相关关系，与脯氨酸含量之间存在抛物线形相关关系.土壤中盐分的增加不仅影响到植物的生长发育，而且对土壤自身的物理、化学性状也产生不良效应.同时测定了盆栽土壤中葡萄糖苷酶和左旋天门冬酰胺酶活性的变化.结果表明,两种酶活性都随土壤中盐分浓度的提高而下降.当盐分浓度为0.2%、0.4%、0.6%和0.8%时，P₁土壤中葡萄糖苷酶活性分别比对照下降了10.96%、20.07%、30.96%和37.44%；而P₂土壤中葡萄糖苷酶活性分别比对照下降11.21%、18.94%、34.89%和41.31%，说明盐分对土壤的理化性状和肥力状况都产生了不良影响.参试的2个无性系中，P₁的耐盐能力强于P₂.

Effects of salinity stress on poplars seedling growth and soil enzyme activity

A pot culture experiment with two clones of poplars (P1 and P2) showed that soil salinity had a definite inhibitory effect on the establishment and growth of seedlings. The survival rate, seedling height and weight, and root weight were all declined with increasing soil salinity. When the salinity was 0.2%, 0.4%, 0.6% and 0.8%, the shoot growth of P1 and P2 decreased by 23.24%, 48.56%, 70.76% and 83.33%, and 71.77%, 83.25%, 86.28% and 91.39%, respectively, in comparing with the control. Regressive analyses showed that soil salinity had a linear relationship with chlorophyll content, and a binomial relationship with leaf proline content. The activities of soil beta-glucosidase and L-asparaginase were decreased with increasing soil salinity. When the salinity was 0.2%, 0.4%, 0.6% and 0.8%, the beta-glucosidase activity in P1 and P2 soils decreased by 10.96%, 20.07%, 30.96% and 37.44%, and 11.21%, 18.94%, 34.89% and 41.31%, respectively. The salinity tolerance of P1 was better than that of P2.