土壤盐度对加拿利海枣幼苗生长与生理指标的影响

将加拿利海枣(Phoenix canariensis Hort. ex Chab.)幼苗培养在不同盐度(1.2~14.5)的土壤中,探讨土壤含盐量对其生长及生理指标的影响。结果表明:随基质盐度的提高,幼苗新生叶片数降低且叶片死亡数增加。随基质盐度的提高,叶绿素含量增加,叶绿素a/b在低盐度时增加而当盐度超过5.1时下降。土壤盐度在1.2~5.1时,MDA含量约为4.30 μmol g^-1,以后随土壤盐度的升高而升高。SOD活性在低盐时升高,土壤盐度超过10.8时,SOD活性迅速下降。盐胁迫下叶片Na⁺和Cl^-含量升高,K⁺、Ca²⁺、Mg²⁺含量及K⁺/Na⁺下降。盐胁迫导致加拿利海枣生长下降的主要原因是叶片有效光合面积减少,离子平衡破坏。这些表明加拿利海枣具有很高的耐盐能力,其幼苗在土壤盐度5.1时生长正常,当土壤盐度为10.8时才开始出现受害症状,适宜在滨海地区推广应用。

Influence of Soil Salinity on Growth and Physiological Indexes of Phoenix canariensis Seedlings

The growth and physiology characteristics of Phoenix canariensis seedlings were studied cultured on different soil salinity ranged from 1.2 to 14.5.The results showed that the number of new leaves decreased and death leaves increased with soil salinity increment.The chlorophyll content increased under high soil salinity,while chlorophyll a/b increased under low salinity and declined under high salinity more than 5.1.MDA content maintained about 4.30 μmol g-1 under salinity from 1.2 to 5.1,then increased with soil salinity.The SOD activity increased under low salinity,while decreased rapidly when salinity higher than 10.8.Under salt stress,Na+ and Cl-contents in leaves increased,while K+,Ca2+ and Mg2+ contents and ratio of K+/Na+ declined.The main reasons of growth decline under salt stress were effective photosynthetic area decrease and destroy of ions balance.These indicated that Phoenix canariensis displayed high resistance to salt stress was suitable to plant widely in coastal districts,which could grow normally under soil salinity lower than 5.1 and only shown damage symptoms above salinity of 10.8.