四种外生菌根真菌对黑松吸收转运镉的影响
毕业论文关键词：外生菌根真菌；镉；宿主植物；促进吸收
Effects of four Ectomycorrhizal Fungi on Absorption and Transport of Cadmium in Pinus thunbergii Parl
Abstract：We examined the effects of four ectomycorrhizal fungi (EMF), Laccaria amethystina (La), Pisolithus tinctorius (Pt), Cenococcum geophilum (Cg), and Laccaria laccata (Ll), on the absorption and transport of cadmium (Cd) in plant hosts. First, in pure culture experiments, we determined the Cd tolerance of the EMF species, which was, from highest to lowest, La > Ll > Pt > Cg, with 50% inhibition concentration (EC50) values of 12.50, 7.75, 2.68, and 0.34 mg kg−1, respectively. Then, in root bag experiments, Pinus thunbergii Parl. seedlings either alone or inoculated with each of the four EMF species were exposed to soil amended with 0, 30, 75, or 150 mg kg−1 Cd. Inoculation with EMF improved the host plants’ Cd tolerance compared to the non-inoculated seedlings. Furthermore, external hyphae were able to absorb Cd outside the root bag and transfer it to the host plant, and strains with higher Cd tolerances were associated with greater heavy metal accumulation in both the rhizosphere and the whole plants. These results demonstrate the role of EMF in promoting heavy metal absorption by host plants and show that EMF does not inhibit heavy metal absorption in host plants. Instead, EMF increases heavy metal tolerance in host plants by improving plant nutritional status and promoting plant growth, diluting heavy metal concentrations in the process.
Key words: Ectomycorrhizal fungi; cadmium; host plants; promote absorption
目 录
摘要 1
关键词1
Abstract 1
Key words 1
引言1
1材料与方法2
1.1外生菌根真菌的Cd耐性2
1.2外生菌根黑松准备2
1.3基质准备2
1.4实验设计3
1.5测定指标及方法3
1.6数据处理4
2结果与分析 4
2.1 4种EMF对Cd的耐性 4
2.2菌丝生长情况 4
2.3生物量5
2.4植物体内Cd浓度 6
2.5 Cd的固定6
2.6植物营养水平7
3 讨论 8
致谢9
参考文献 10
四种外生菌根真菌对黑松吸收转运镉的影响重金属是指密度大于5 g cm-3的元素，主要包括过渡金属、部分类金属、镧系以及锕系元素[1]。重金属在土壤中自然发生并且浓度变化很大。尤其是因为工业活动的迅速扩张和重金属的难降解性，它们在环境中不断积累[2]。Cd作为一种生物非必需重金属元素，生物半衰期很长，是一类存在较广的衡量环境污染物[3]。土壤中的Cd能被植物吸收并在可食用部位积累，最终会通过食物链进入人体内，给人类健康带来了巨大的威胁 [4]。因此，修复Cd污染土壤对于人类的健康和环境的保护尤其急迫。