重金属Cr6+胁迫对茳芏生理生态特征的影响

Physiological and ecological characteristics of Cyperus malaccensis to Cr6+ stress

关键词:  Cr⁶⁺  茳芏  胁迫  生理生态特征

Key words:  Cr⁶⁺  Cyperus malaccensis  stress  physiological and biochemical characteristics

摘要:

采用盆栽模拟试验,研究了不同水平重金属Cr⁶⁺对茳芏生理生态的影响,探索了茳芏对重金属的抗性机理,充实有关盐沼植物的污染生态学研究。结果表明:(1)Cr⁶⁺胁迫对茳芏生物量具抑制作用;(2)叶绿素含量及叶绿素a/b比值显著降低,并对净光合速率(Pn)、胞间 CO₂浓度(Ci)、蒸腾速率(Tr)及气孔导度(Gs)产生显著负面影响;(3)各浓度Cr⁶⁺胁迫对茳芏根系活力表现为抑制效应;(4)在Cr⁶⁺胁迫下,茳芏过氧化氢酶(CAT)活性均比对照低(除50mg/L外),超氧化歧化酶(SOD)活性随 Cr⁶⁺浓度增加呈降低趋势,而过氧化物酶(POD)活性则持续上升。丙二醛(MDA)、细胞膜透性和脯氨酸(Pro)随Cr⁶⁺浓度增加显著增加,表明Cr⁶⁺胁迫对茳芏细胞质膜系统及主要细胞器的结构与功能都具有较强的破坏作用。

Abstract:

This study adopted a simulated experiment method by the means of planting Cyperus malaccensis in pots in order to study the different concentrations of Cr⁶⁺ stress effects on the plant eco-physiological characteristics and its resistance to the stress,aiming to obtain the species's toxicity mechanisms as well as its resistance to the metal,so as to provide reference to the pollution ecology of salt marsh plants. The results were as follows:(1)The biomass was inhibited drastically as the stress increased;(2)The contents of chlorophyll and the ratio of chlorophyll a and chlorophyll b reduced obviously,and there were obviously negative effects to net photosynthesis rate(Pn), intercellular CO₂ concentration(Ci), transpiration rate(Tr)and stoma conductivity(Gs);(3)The root vigor was inhibited significantly under Cr⁶⁺ stress;(4)The activity of CAT under Cr⁶⁺ stress were lower than the control group(except the concentrations of 50 mg·L^-1), the activity of SOD decreased, but the activity of POD increased all the time. The contents of MDA,proline and cytomembrane permeability increased obviously with the increasing of Cr⁶⁺concentrations. Therefore, it highlighted that the Cr⁶⁺stresses could mangle the cytomembrane system,the structures and functions of the major organelles of tea plant.