盐旱胁迫对3种新疆造林树木种子萌发的影响

Seeds Germination of Three Common Afforestating Trees under Salt and Drought Stress in Xinjiang

以3种新疆常见造林树木白榆、大叶白蜡、梭梭种子为材料,通过测定不同土壤含盐量(0.1%～0.5%)和含水量(9%～23%)复合胁迫作用下种子的发芽率、发芽指数,以探讨3种种子萌发对盐分和干旱胁迫的响应特征.结果显示:(1)梭梭种子对盐和干旱胁迫的适应范围最广,大叶白蜡次之,然后是白榆.(2)在土壤含盐量不超过0.2%情况下,土壤含水量达到17%以后,3种树木种子发芽率都在50%以上;而当土壤含盐量为0.3%时,3树种种子仅在23%含水量下有较高发芽率;0.4%土壤含盐量条件下,只在含水量为23%时,梭梭、大叶白蜡萌发率能达到50%以上;0.5%土壤含盐量时,仅梭梭种子萌发率达到50%.(3)白榆、大叶白蜡、梭梭的耐旱临界值分别为15.1%、10.7%、9.6%,耐盐临界值分别为0.34%、0.41%、1.03%.研究表明,盐旱胁迫存在明显互作效应,盐旱复合胁迫对种子萌发的危害性明显强于单一的盐胁迫或旱胁迫.

Based on investigating seeds germination and germination index of Ulmus pumila L.,Fraxinus rhynchophylla Hance and Haloxylon ammodendron（C.A.Mey.） Bunge under different content of soil salt and water content,we discussed the response of seeds germination of those three familiar afforestating trees to salt and drought stress.The results showed that：（1）the adaptive capacity of H.ammodendron seeds was the best of all,and then F.rhynchophylla,U.pumila at last.（2）When the content of soil total salt under 0.2% and soil moisture reach 17%,the seeds germination of all three trees were over 50%.While the content of soil total salt at 0.3%,the three trees had better seeds germination just at the soil moisture of 23%.At the condition of 0.4% soil total salt,the seeds germination of H.ammodendron and F.rhynchophylla could reach 50% with the soil moisture of 23%.And just the seeds germination of H.ammodendron could reach 50% at the soil total salt of 0.5%.（3）The drought critical value of U.pumila,F.rhynchophylla and H.ammodendron was 15.1%,10.7% and 9.6%,respectively and the salt critical value was 0.34%,0.41% and 1.03%,respectively.It can be clearly seen that salt and drought stress have obvious interaction effects,and the harmfulness of salt and drought combined stress on seeds germination was more serious than single salt or drought stress.