【作者】 顾艳红；

【导师】 刘鹏；

【作者基本信息】 浙江师范大学 ， 植物学， 2008， 硕士

【摘要】 苔藓植物作为非常敏感的污染指示植物,已被广泛应用于重金属污染的监测。本文采用室内模拟培养、生理生化测定、显微观察等实验手段,研究了铜(Cu²⁺)污染对多蒴灰藓（Hypnum fertile）及其伴生藓金发藓（Polytrichum commune）、东亚小金发藓（Pogonatum inflexum）和大羽藓（Thuidium cymbifolium）这4种苔藓植物的毒害作用,其中重点研究了铜(Cu²⁺)、镉(Cd²⁺)单一及其复合污染对多蒴灰藓的毒害作用。研究结果摘要如下:1.研究了不同浓度的Cu²⁺污染对多蒴灰藓及其3种伴生藓的生理特性的影响,结果表明,Cu²⁺污染对4种藓类植物的叶绿素含量、丙二醛（MDA）含量、游离脯氨酸（Pro）含量以及过氧化氢酶（CAT）活性均有不同程度的影响。其中多蒴灰藓对Cu²⁺污染最为敏感,大羽藓次之,东亚小金发藓和金发藓对Cu²⁺污染表现出了较强的耐性。2.不同浓度的Cu²⁺、Cd²⁺单一及其复合污染不同时间下对多蒴灰藓外部形态以及茎解剖结构的影响表明,不同浓度的Cu²⁺、Cd²⁺对多蒴灰藓造成不同程度的伤害,培养浓度、培养时间与伤害程度呈正相关。随着Cu²⁺、Cd²⁺处理浓度的增加,多蒴灰藓表现出逐渐严重的伤害症状,植株失绿,解剖结构也表现出明显异常,茎皮部细胞木质化程度加深。且Cd²⁺污染影响要明显大于相同浓度相同时间处理下的Cu²⁺污染,Cu²⁺、Cd²⁺复合污染毒性效应要大于单一污染。3.Cu²⁺、Cd²⁺单一及其复合污染下重金属在生物体内积累过程较慢,而细胞外生物吸附作用则极其快,这一负作用过程在一定的时间内可以达到平衡,并且大部分的重金属是被吸附在细胞壁上而没有进入细胞内的。Cu²⁺、Cd²⁺单一及其复合污染对矿质元素吸收的影响表明重金属污染造成多蒴灰藓体内K、Ca、Fe、Mg元素含量不同程度的下降,其中复合污染的效应要明显大于单一污染。4.在Cu²⁺、Cd²⁺两种离子的作用下,多蒴灰藓体内与逆境密切相关的物质和保护酶发生一系列的变化,且表现出明显的剂量/效应关系和时间/效应关系。随着处理浓度的加大、处理时间的延长,叶绿素含量、可溶性蛋白含量等生理指标下降;低浓度短时间处理诱导可溶性糖、丙二醛、游离脯氨酸、抗坏血酸含量和过氧化氢酶活性等生理指标上升,但随着污染时间的延长和污染浓度的增加,这些生理指标又呈现下降趋势。其中,Cu²⁺、Cd²⁺复合污染比单一污染的毒性大,二者对上述生理指标的影响呈现明显的协同作用。5.以苔藓植物多蒴灰藓为实验材料,用不同浓度的重金属镉处理7 d后,借助傅立叶红外光谱法（FTIR）分析重金属镉胁迫下多蒴灰藓各化学成分的变化,同时测定可溶性糖（SS）、可溶性蛋白（Pr）、丙二醛含量（MDA）三种重金属胁迫生理指标。结果发现,随着镉处理浓度的升高,SS含量和Pr含量呈现先上升后下降的趋势,MDA含量先下降后上升。傅立叶变换红外光谱的分析与多蒴灰藓响应重金属镉胁迫的各生理指标变化趋势较一致,且傅立叶红外光谱法比传统的生理指标测定更敏感、便捷。因此,傅立叶变换红外光谱法可以作为研究苔藓植物应用于环境重金属污染监测的一种快速、有效的方法。更多还原

【Abstract】 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.更多还原