镉胁迫对茳芏生理生态特征的影响

Effect of Cadmium Stress on the Physiological and Ecological Characteristics of Cyperus malaccensis L.

[目的]从生理生态学角度揭示镉污染对盐沼植物环境的破坏,探索植物受毒害过程与抗性机制,以期为重金属污染植物的生态毒理学研究提供科学依据。[方法]以茳芏为供试材料,用盆栽试验研究了镉胁迫下茳芏生理生态响应及耐性机理。以植株的株高、地下直径、地上茎直径、地上部分和地下部分鲜重及干重为基本生理指标,以叶面积指数、叶绿素a、b含量、可溶性蛋白含量、可溶性总糖含量和CAT、POD酶活性为生化指标,描述镉胁迫下的茳芏生理生长过程。[结果]低浓度镉胁迫对茳芏生长起促进作用,当Cd2+≥5.0mg/L时则表现为抑制效应,且浓度越高抑制作用越明显;叶绿素随镉浓度的增加而逐步降低,且镉胁迫对叶绿素a的抑制作用大于叶绿素b;根系活力和可溶性蛋白在镉胁迫下呈现出"低促高抑";可溶性总糖在镉浓度(Cd2+≤10 mg/L)呈上升趋势;CAT随镉浓度的增加先升后降,而POD活性持续升高。说明镉在一定程度上对茳芏生长生理起促进作用,而高浓度镉(Cd2+≥5.0 mg/L)则抑制茳芏生长。[结论]茳芏的抗逆性较强。

[Objective] To reveal the destructive effect of cadmium pollution on salt marsh plant environment from physiological ecology perspective,and investigate the injured process and resistance mechanism of plant,aiming at provide scientific basis for the ecotoxicology research on heavy metal polluted plants.[Method] Cyperus malaccensis L.was taken as test material,the physiological response and resistance mechanism of which under cadmium stress were investigated.Plant height,rhizome diameter,fresh and dry weights of aboveground and underground parts were taken as physiological indexes.Leaf area index,contents of chlorophyll a,b,soluble sugar and soluble protein,activities of CAT,POD were taken as biochemical indicators.[Result] Low concentration of cadmium was favorable for the growth of Cyperus malaccensis,while high concentration of cadmium（≥5.0 mg/L） played inhibitory role.Content of chlorophyll decreased with cadmium concentration increased,and chlorophyll a was more vulnerable to cadmium stress.The viability of root system and soluble protein content were improved with low concentration cadmium,and inhibited with high concentration cadmium.Content of soluble sugar was on rise when cadmium concentration was in the range of 0-10 mg/L.The activity of CAT increased first then decreased with cadmium concentration increased,while that of POD kept rising,which suggested within the range of 0-5 mg/L,cadmium was favorable for the growth of Cyperus malaccensis.[Conclusion] Cyperus malaccensis was endowed with strong resistance with strong resistance.