【作者】 孟昭娟；

【导师】 方炎明；

【作者基本信息】 南京林业大学 ， 环境科学， 2009， 硕士

【摘要】 本文以Cd、Pb为胁迫因子,以中华短肠蕨(Allantodia chinensis (Bak.) Ching)和黑足鳞毛蕨(Dryopteris fuscipes C. Chr.)为试验材料,研究了Cd-Pb复合污染在不同浓度、时间对两种蕨生理指标的影响及重金属的累积情况。研究结果表明:(1)在Cd-Pb胁迫下,中华短肠蕨、黑足鳞毛蕨的外部形态发生一定变化,主要表现为:随浓度增大时间延长,叶片逐渐褪绿,甚至枯死,新生卷拳叶数量减少,生长缓慢。存在典型的剂量/效应和时间/效应关系。(2)对中华短肠蕨和黑足鳞毛蕨在胁迫下的生理指标分析表明,Cd-Pb胁迫使两种蕨的叶绿素含量明显降低,a/b升高。SOD、POD活性、GSH和ASA含量具有低浓度下的激活效应和高浓度下的抑制效应。从生理指标变化来看,中华短肠蕨生理抗性强于黑足鳞毛蕨。(3) Cd-Pb胁迫初期两种蕨细胞超微结构基本完整,胁迫浓度增大到1.2+1200mg/kg时,类囊体肿胀,膨大变形,片层结构不清楚,细胞壁扭曲变形,细胞器降解,细胞核结构受到破坏,核膜不清晰,质壁分离,有黑色物质沉积。(4)能谱元素测定发现,中华短肠蕨和黑足鳞毛蕨对Pb均有较强的富集能力,在一定浓度范围内,两种蕨中铅元素主要集中在羽叶和叶柄,部位累积能力是羽叶〉叶柄〉根,但当浓度增大到一定程度时,向上转运铅的能力减弱。二者均有作为植物修复物种的潜力。更多还原

【Abstract】 This paper is about the effects of Cd-Pb stress on Allantodia chinensis (Bak.) Ching and Dryopteris fuscipes C. Chr.,focusing on physiological responses of two fern species to different metal concentration and stress time of. cadmium and lead, as well as their accumulation situation. The results showed:(1).Under Cd -Pb stress, external form of A. chinensis and D. fuscipes changed to certain extents.The chief performance was characterized by the following aspects. With increase of concentration and prolonging of time, leaves faded green gradually, even died. The number of sproutd young leaves decreased. Plant grew slowly. Typical relation of dose/effect and time/effect occurred for the two ferns.(2).Analysis of physiological indices of A. chinensis and D. fuscipes under Cd-Pb metal stress indicated that ,chlorophyll contents in the two ferns decreasd significantly, and chlorophyll a/b ratio rised. Metal stress had a positive effect in lower concentration and a negative one in higher concentration in the activities of Superoxide Dismutase (SOD) and Peroxidase(POD), as well as the contents of Glutathione (GSH) and Ascorbic Acid (ASA). We concluded that A. chinensis had stronger resistance to Cd -Pb stress than D. fuscipes based on physiological indices.(3). In the early stages of Cd-Pb stress, cell ultrastructure of the two ferns were complete and unwounded. When the concentration increase to 1.2+1200mg/kg, chloroplast deformed obviously, chloroplast thylakoids became indistinct, and cell wall distorted. Organelles were degraded, nucleolus structures destroyed, and nuclear membrane blurred. Cells were plasmolyzed, and some black substance deposited on the cell wall.(4).By means of SEM-EDX, we found that A. chinensis and D. fuscipes had strong ability to enrich lead. Within certain concentrations of metals, Lead in the two ferns mainly concentrated on leaves and petiole. It is also clear that the organ with maximum ability of metal accumulating was leaves, while the organ with minimum ability of metal accumulating was roots. When the concentrtion increased to certain extents, the transporting ability of lead was weak. The two ferns were potential material for phytoremediation.更多还原