NaCl胁迫对不同品种黄瓜幼苗生长、叶绿素荧光特性和活性氧代谢的影响

The Effects of NaCl Stress on Plant Growth,Chlorophyll Fluorescence Characteristics and Active Oxygen Metabolism in Seedlings of Two Cucumber Cultivars

研究了NaCl胁迫下黄瓜‘津研4号’(耐盐性较强)和‘津绿4号’(耐盐性较弱)植株生长、叶片叶绿素荧光特性和活性氧代谢的影响。结果表明,NaCl胁迫明显降低植株生长量、叶片叶绿素含量、PSII非环式电子传递量子效率(ΦPSⅡ)、初始荧光(Fo)和非光化学猝灭系数(NPQ),而对光化学效率(Fv/Fm)的影响不大。‘津研4号’幼苗生长受盐胁迫的影响小于‘津绿4号’,其光合机构受盐胁迫的伤害程度小于‘津绿4号’。随NaCl浓度增加,黄瓜叶片AsA-POD活性升高,而‘津绿4号’叶片SOD活性降低。盐胁迫增加叶片O2·产生速-率、H2O2和MDA含量,尤其是‘津绿4号’叶片中更明显。因此,可以推论,盐胁迫下较高的SOD活性、较低的H2O2和MDA含量与‘津研4号’较高的耐盐性有关。

Two cucumber (Cucumis sativus L.)cultivars,‘Jinyan 4’ (salt tolerant) and ‘Jinlü4’ (salt sensitive) were grown in nutrient solutions with three NaCl levels(0,25,50 mmol·L-1)for the investigation of plant growth, chlorophyll fluorescence and active oxygen metabolism in seedling leaves. The results showed that NaCl stress decreased plant growth, chlorophyll content, quantum yield of PSII (ΦPSII),initial fluorescence yield(Fo)and non-photochemical quenching of fluorescence(NPQ). The plant growth of ‘Jinyan 4’ was less affected by salt stress than ‘Jinlü4’ and the photosynthetic apparatus was less injured by salt stress than ‘Jinlü4’. However, photochemical efficiency of PSII (Fv/Fm) was not affected by salt stress. Meanwhile,salt stress significantly increased the activity of ascorbate peroxidase (AsA-POD) and significantly decreased superoxide dismutase (SOD) activity in ‘Jinlü 4’. Free radical producing rate, and H2O2 and MDA content increased with increasing NaCl levels, however, less H2O2content and lipid peroxidation were observed in the leaves of ‘Jinyan 4’ than ‘Jinlü4’. It is concluded that higher SOD activity, less H2O2 and MDA content may be involved in higher salt tolerance of ‘Jinyan 4’.