【摘要】 以10 mmol/L Pb(NO3)2处理紫花苜蓿幼苗10 d,分析了Pb在紫花苜蓿幼苗根、茎、叶中的积累情况,Pb在根表皮细胞中的亚细胞区域化特点,以及Pb在紫花苜蓿体内的主要存在形式。结果表明,Pb在紫花苜蓿幼苗中积累量(M)特点为:M根 >M茎 >M叶。同时X-ray微区分析显示,胞间隙是紫花苜蓿积累Pb浓度最高的部位,细胞壁和液泡次之,胞质中最低。Pb的存在形式分析表明Pb在紫花苜蓿体内主要以难溶的形式存在,另外BSO能够加剧Pb污染对紫花苜蓿幼苗Pn和生长的抑制作用,显示了紫花苜蓿对Pb的耐受与植物络和素的形成有关。这些都表明紫花苜蓿对Pb具有一定的耐受机制,避免其对胞质代谢的毒性。同时紫花苜蓿具有很高的生物量和对Pb较高的富集作用,因此是一种很有利用价值的土壤铅污染修复植物。更多还原

【Abstract】 After being treated with 10 mmol/L Pb(NO3)2 for 10 days, alfalfa (Medicago sativa L.) seedlings were analyzed for Pb contents in the different parts (roots, stems and leaves) of the plant, subcellular compartmentation of Pb in the epidermal cells in roots by X-ray microanalysis and the main chemical forms of Pb in the plant body. Results showed that the trait of Pb accumulation (M) in alfalfa seedlings was Mroot>Mstem>Mleaf. At the same time X-ray microanalysis indicated that Pb relative content in the inter-cellular space was the highest, followed by that in cell wall and vacuoles and the lowest Pb concentration was recorded in the cyto-plasma. The determination of Pb chemical forms demonstrated that Pb was accumulated in alfalfa seedlings mainly in insoluble forms. All of this indicated that he plant was competent to stand Pb contamination to some degree and avoid its toxicity with the certain mechanisms. At the same time alfalfa had a very high biomass and was able to accumulate relatively high Pb content in its body, indicating that the plant may be valuable in the phytoremediation of Pb-contaminated soil.更多还原