不同N、P浓度条件下龙须菜对镉胁迫的生理响应

Physiological response of Gracilaria lemaneiformi to stress of heavy metals Cd^(2+) under the conditions of different nitrogen and phosphorus

通过室内生态学对比实验,研究了龙须菜(Gracilaria lemaneiformis)在不同N、P营养盐浓度条件下对重金属Cd2+胁迫的生理响应。结果表明,环境中加入适当浓度的N、P营养盐(N280μmol/L、P56μmol/L)有利于提高龙须菜光合色素的含量和生长率,同时藻体内超氧化物歧化酶(SOD)和过氧化物酶(POD)酶活性增高,丙二醛(MDA)含量降低,从而增强了龙须菜对重金属Cd2+胁迫的耐受性;而N、P饥饿(N、P均为0μmol/L)或N、P营养盐浓度过量(N、P分别为216μmol/L、1620μmol/L)状态下,龙须菜抗氧化能力下降、脂质过氧化和膜系统受伤害程度加剧,光合色素合成和生长率受到抑制,不利于龙须菜对重金属Cd2+胁迫的生理适应。

The physiological response of Gracilaria lemaneiformi exposed to stress of heavy metals Cd^2＋ was studied under the conditions of different nitrogen and phosphorus and through the indoor ecological experiment. It was found that adding an appropriate concentration phosphate salt（56μmol/L） or nitrogen salt （280 μmol/L） into the environment profited to improve the content of photosynthetic pigments of G. lemaneiformis and growth rate of the algae body at the same time, and increase their SOD and POD activities, decreased their MDA content, thus increasing their tolerance towards the heavy metal Cd^2＋ stress. On the status of nitrogen or phosphorus starvation （0 μmol/L） or excessive nutrient concentrations of phosphorus （216μmol/L） or nitrogen（1 620 μmol/L）, the G. lemaneiformis＇s antioxidant capacity was declined, the harm degrees of lipid peroxidation and membrane system were increased, as well as the synthesis of photosynthetic pigments and the growth rate were inhibited. And the physiological adaptation of G. lemaneiforrnis to heavy metal Cd^2＋ stress is disadvantageeuas.