白刺对不同浓度混合盐碱胁迫的生理响应

Effect of complex saline-alkali stress on physiological parameters of Nitratia tangutorum

为研究白刺(Nitratia tangutorum)对盐碱生境的适应能力,对二年生白刺实生苗进行了20组不同盐、碱浓度的胁迫处理。研究结果表明:随着盐、碱浓度加大,白刺叶片质膜所受伤害逐渐增加,在300mmol·L-1盐浓度下,白刺膜透性大幅度增加,电解质大量外渗,质膜的选择透过性遭到破坏;丙二醛作为膜脂过氧化的产物,它的变化规律与质膜透性的变化规律相一致,两者呈极显著正相关(r=0.796);白刺叶片中的超氧化物歧化酶、过氧化物酶和过氧化氢酶活性随着盐胁迫浓度和pH的增加而有不同程度的升高,增强了清除细胞内活性氧的能力,对膜系统起到了一定的保护作用;线性回归分析表明对白刺生长有重要影响的4个胁迫因素的重要性排序是盐浓度>pH>[HCO3-]>[CO32-]。综合各项指标,盐浓度在300mmol·L-1以下,pH小于10.59时,白刺能够较好耐受,具有较强的耐盐碱适应能力。

Aims Our objective was to investigate the saline-alkali tolerance mechanism of Nitratia tangutorum to provide the basis for its use in saline areas in Heilongjiang Province of China and contribute to the theoretical understanding of urban tree species.Methods We treated seedlings of N.tangutorum to 20 kinds of mixed salt solutions with different salinities and alkalinities and examined saline-alkali stress on lipid peroxidation and enzyme activities.Important findings Injury to the plasma membrane of leaves increased with increasing salinity and alkalinity.Cell membrane permeability and electrolyte leakage of leaves were enhanced under salinity of 300 mmol·L^-1.The selectivity of plasma membrane permeability was damaged.The variation of malondialdehyde lipid peroxidation as plasmalemma peroxide product was consistent with that of electrolyte leakage,which showed a significant positive correlation（r = 0.796）.The activities of superoxide dismutase,peroxidase and catalase increased with both increased salinity and pH,which enhanced the ability of the active cell membrane system.Linear regression analysis showed that the significance order of four stress factors is salinity pH [HCO3^-] [CO3^2-].Nitratia tangutorum had a high tolerance to complex saline-alkali stress when the salinity was〈 300 mmol·L^-1 and pH was 〈10.59.