盐胁迫对海滨雀稗生长和生理特性的影响

本研究采用不同浓度NaCl溶液(0,100,200,300,400和500 mmol/L)对海滨雀稗进行盐处理,测定了生长势、生物量、叶片相对含水量、质膜透性、叶绿素含量、渗透调节物质含量以及抗氧化酶活性等指标,分析不同程度盐胁迫对海滨雀稗生长和生理特性的影响,并且对其耐盐性进行了评价。结果表明,NaCl胁迫对海滨雀稗的株高、叶长、叶宽和直立茎茎粗产生了抑制作用,对根、茎和叶的干物质积累产生显著影响,并且随着盐浓度的增加呈逐渐降低的趋势;海滨雀稗叶片相对含水量随着NaCl浓度的增加呈下降趋势,而质膜透性、叶绿素(Chl)、丙二醛(MDA)和可溶性糖含量则呈升高趋势;海滨雀稗叶片脯氨酸含量、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性均在300 mmol/L NaCl浓度下达到最大值,而且都随NaCl浓度的增加呈先升高后降低的趋势,表明海滨雀稗具有较高的耐盐能力,在盐胁迫下可采取自我保护机制以适应盐逆境,其耐盐阈值为300 mmol/L NaCl浓度。以上生理指标的动态变化反映出海滨雀稗对盐逆境的适应性变化,是抵御盐胁迫的一种积极调节机制。

Impacts of salt stress on the growth and physiological characteristics of Paspalum vaginatum

The effects of different concentrations of NaCl solution (0,100,200,300,400 and 500 mmol/L)on growth,biomass,relative water content,membrane permeability,photosynthetic pigments,organic osmolyte content and protective enzyme activity of Paspalum vaginatum were assessed to determine the response of growth and physiological parameters to salt stress.The results indicated that plant height,leaf length,leaf width,root dry weight,stem dry weight,leaf dry weight and erect stem diameter of P .vaginatum under NaCl treatment were significantly reduced compared with the control (no salt).Compared with the control,the rela-tive water content of P .vaginatum leaves was decreased significantly,while the membrane permeability,pho-tosynthetic pigment,MDA and soluble sugar content increased.The activities of SOD and POD and leaf pro-line content all increased at lower salt levels and then declined,peaking at 300 mmol/L NaCl.This study showed that P .vaginatum has self protecting mechanisms providing tolerance to salinity stress;the threshold of salt tolerance was 300 mmol/L NaCl.The improvement of salt-tolerance in P .vaginatum resulted from themodulation of physiological characteristics.