镉污染环境下中华蚊母树的镉积累与生长及叶绿素荧光动力学响应

摘要

Distylium chinense (growth similar), a dominant species in the Three Gorges Reservoir area, is selected as object for the study to investigate responses of the tree to Cd stress in Cd accumulation, growth and chlorophyll fluorescence parameters.Results show that Cd stress, moderate and high in concentration, inhibited significantly growth in height and total chlorophyll content of the plant under stress.Chlorophyll fluorescence parameters of the plant can be used to explain Cd tolerance of the plant physiologically.Cd stress damaged the plant′s photoreactive center PSⅡ, though reversibly.Chlorophyll fluorescence parameters (Fv/Fm and RET) declined first and gradually came back with the stress going on.Under the Cd stress of 2 mg·kg-1, Cd enrichment coefficient of the plant reached up to 7.4, 8.1 and 8.2 in roots, stems and leaves, respectively, and Cd transfer coefficient up to 1.01 and 0.94 in stem and leaves, respectively.Obviously Distylium chinense possesses a high Cd accumulation and transfer capacity.According to the pollution status of the Three Gorges Reservoir area, Distylium chinense can be used as a potential species for phytoremediation of Cd contaminated soils.%以三峡库区优势物种中华蚊母树(Distylium chinense)为试验对象,在其生长土壤中添加不同w(Cd2+)(0、2、5、15、30 mg·kg-1),研究植物镉积累、生长高度及叶绿素荧光参数对不同含量镉胁迫的响应.结果表明,中、高含量镉胁迫对植物的生长高度及叶绿素总量具有显著抑制作用;叶绿素荧光参数对植物的耐受性可以进行生理学解释,镉胁迫下植物光反应中心PSⅡ受到可逆性损伤,叶绿素荧光参数Fv/Fm与RET值随胁迫时间先降低后逐渐恢复;添加w(Cd2+)为2 mg·kg-1时,根、茎、叶的镉富集系数最大,分别为7.4、8.1和8.2;茎、叶的转移系数最大,分别为1.01和0.94;中华蚊母树具有很强的富集性和转移能力,可以作为镉污染土壤植物修复技术的潜能物种.