Toxic Effect Of Cu²⁺,Cd²⁺ Pollution On Hypnum Fertile Sendtn.

As a very sensitive indicator to pollution,moss has been widely used to monitor heavy metal pollution.In this paper,we studied the toxic effects of Cu²⁺ pollution on Hypnum fertile,Polytrichum commune,Pogonatum inflexum and Thuidium cymbifolium by means of simulated test,measurement of physiological index observation of microstructure,with the most important content of the toxic effects of Cu²⁺,Cd²⁺and their combined pollution on Hypnum fertile.The experimental results showed:1.The effects of Cu²⁺pollution on the physiological characteristics of Hypnum fertile,Polytrichum commune,Pogonatum inflexum and Thuidium cymbifolium indicated that the chlorophyll,MDA,Pro content and the CAT activity were influenced by different concentrations of Cu²⁺.Hypnum fertile Sendtn.is more sensitive to Cu²⁺pollution than Thuidium cymbifolium,while Polytrichum commune and Pogonatum inflexum were available to Cu²⁺ pollution.2.Different stress concentrations of Cu²⁺,Cd²⁺led to different poisoning symptoms to Hypnum fertile and the injury on external morphology has a positive correlation with culture concentration and time.With the increase of stress concentration and stress time,the poisoning symptoms became more and more serious.Mainly symptom was losing green,some mosses materials even died in high stress concentration at last.The anatomical structure also showed abnomal.The degree of lignification of cells in stem cortex got much heavier. Experimental results indicated that toxicity of Cd²⁺on mosses is heavier than that of Cu²⁺under the same treating time and concentration,and the effects of combined pollution are stronger than those of single pollution.3.The heavy metal content of leaves of Hypnum fertile Sendtn.after exposuring to Cu²⁺and Cd²⁺7d and 14d indicated that bioaccumulation proceeded slowly whereas extracellular biosorption was an extremely rapid and passive process,reaching equilibrium within some time,while most of the heavy metal content had not entered into the cell.Effects of Cu²⁺,Cd²⁺pollution on K,Ca,Fe,Mg mineral contents of Hypnum fertile Sendtn.indicated that the content of K,Ca,Fe,Mg of Hypnum fertile Sendtn.obviously decreased with enhancing treatment concentration and time,and the effects of Cu²⁺and Cd²⁺ combined pollution were stronger than those of single pollution.4.Under the stresses of Cu²⁺and Cd²⁺,a series of change occurred in the substance and protective enzymes related with the adversity,and all indexes demonstrated a correlation between the does and effect,the higher the pollution concentration and the longer the pollution time are,the more serious the damage is.Chlorophyll content and soluble protein content deceased with enhancing treatment concentration and time.The SS content,MDA content,Pro content and ASA content increased first and deceased afterwards with enhancing treatment concentration and time.Under low concentration stress and short time treatment,protective systems reacted on Hypnum fertile Sendtn.,the activitie of CAT was induced in high level to eliminate and resolve ractive oxygen species(ROS)in order to maintain stability of membrane systems.But with more serious damage,the defensive system of cells could not protect cells.The effects of Cu²⁺and Cd²⁺combined pollution were stronger than those of single pollution.5.Bryophytes are accepted as indicator plants for monitoring the pollution degree of heavy metal in environment.In this paper,Fourrier transform infrared spectrometer was applied to gain the infrared spectra of Hypnum fertile Sendtn. samples with different concentration of Cd²⁺for 7 days to study the changes of chemical components,and some physiological characteristics such as malondialdehyde(MDA),solubility sugar(SS)and solubility protein(Pr)were also studied.The results showed that with enhancement of the Cd²⁺ concentration,the content of solubility sugar and solubility protein were enhanced at first and followed decreased.However,it was just the opposite for the content of malondialdehyde.Based on the indices of wave number-absorbance,the differences of the samples with different concentration of Cd²⁺infrared spectra were compared by the changes of the physiological characteristics.The results showed that there was good correspondence between the changes of the physiological characteristics and the changes of samples based on the indices of wave number-absorbance of FTIR spectra,and the FTIR was more sensitivity and convenient.Therefore,Fourrier transform infrared spectrometer can be accepted as a fast and effective method to study Bryophytes for monitoring the pollution degree of heavy metal in environment.