盐胁迫对枸杞(Lycium barbarum)叶片生理的影响

Effect of Single and Mixed Salt Stress on Leaf Physiological Characteristics of Lycium barbarum

枸杞(Lycium barbarum)耐盐碱能力强,在盐渍化土壤中种植枸杞具有一定程度改良土壤的功效。然而对枸杞在不同盐渍生境和不同盐渍化程度下的生理适应基础研究较少。选取扦插的"宁杞5号"一年实生苗为材料,分别在渗透势为-0.48、-0.82、-1.18 MPa下采用单盐(NaCl或Na_2SO_4)和混合盐NaCl+Na_2SO_4进行处理,对比分析不同处理时段内枸杞生理活性的响应。结果表明:随着渗透势降低,叶绿素(Chl)含量呈下降趋势;代表膜脂过氧化程度的丙二醛(MDA)、渗透调节物质脯氨酸(Pro)和可溶性糖(SS)含量明显增加;抗氧化酶系统超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性增加;渗透势为-1.18 MPa盐处理则抑制了过氧化物酶(POD)的活性。相同渗透势的不同盐处理之间,Chl、Pro、MDA和SS含量以及SOD和CAT活性在混合盐处理下或多或少都有增加;随着处理时间的延长,MDA、Pro、SS含量和CAT活性增加。这说明盐渍化程度增加,渗透调节物质和抗氧化酶系统的保护加强;不同盐渍环境下枸杞的生理响应不同,-1.18 MPa下混合盐胁迫相对于单盐影响更大;胁迫时间延长,渗透调节物质的累积增加,枸杞的适应性增强。

Lycium barbarum has strong ability to salt and alkali resistance, and its cultivation in salinized soil can improve soil quality to a certain extent. However, less information was found about physiological ad- aptation to different saline habitats under different salinization level in L. barbarum. In order to analyze the physiological response difference of L. barbarum to single salt （NaC1 or Na2 S04 ） and mixed salt （NaC1 ＋Na2S04 ）, we selected one year seedling of Ningqi No. 5 as the materials to treatment under different sa- line solution with different osmotic potential gradients （--0.48, --0.82 and --1.18 MPa, respectively）. The results showed that chlorophyll （Chl） content decreased, but the content of malondialdehyde （MDA）, proline （Pro） and soluble sugar （SS）, and activities of anti-oxidant enzyme superoxide dismutase （SOD） and catalase （CAT） increased with the decreasing of osmotic potential under different salt treatment. Peroxidase （POD） activity was inhibited at osmotic potential of --1.18 MPa. Among different salt solution with the same osmotic potential, the contents of Chl, Pro, MDA and SS and activities of SOD and CAT more or less increased under mixed salt treatment. MDA, Pro and SS contents and CAT activity increased during treat- ment. All these results suggested that the protective capability enhanced from osmo-regulated substances and anti-oxidant enzyme system of L, barbarum at high salinization level. The physiological responses of L. barbarum were different in different saline environments, and the effect of mixed Salt stress was grea- ter than that of single salt at --1.18 MPa. The accumulation of osmo-regulated substances and ability to sa- line adaptation of L. barbarum increased during salt treatment.