【作者】 房娟；

【导师】 楼崇；

【作者基本信息】 南京林业大学 ， 生态学， 2011， 硕士

【摘要】 本文以苏柳172(Salix jiangsuenses CL’J172’)和垂柳(Salix babylonica Linn.)为试验材料,通过水培和盆栽两种栽培方式,研究了重金属铅(Pb)对其生理生化指标的影响、吸收动力学特性、对重金属胁迫的响应情况以及对土壤酶活性的影响。具体结果如下：1.铅处理显著抑制2种柳树的根系伸长,垂柳根系表面积、根体积、根平均直径出现先增后降,苏柳172根系表面积、根体积、根平均直径均受到铅的显著抑制。2种柳树的根系活力均下降；超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性和脯氨酸(Pro)含量均为先增加后下降；可溶性蛋白含量、叶绿素含量在一定程度内均降低,只是变化的幅度和进程不同。2.在溶液Pb浓度为0.25～100μmol·L-1时,两种柳树对Pb的吸收动力学都呈非饱和曲线,积累量随浓度的增大及时间的延长而增加。垂柳根的吸收力α(Vmax/km)值明显高于苏柳172根的α值,垂柳对Pb的吸收积累能力强于苏柳172。柳树根尖区的Pb含量远远大于成熟区,根尖区是吸收Pb最活跃的区域。施加乙酸和苹果酸一定摩尔浓度配比下可以促进Pb的吸收,施加高浓度苹果酸未促进铅向地上部的运输和根系的吸收。3.盆栽柳树在一个生长期内对Pb的吸收积累量可超过对照植株含Pb量,根系对Pb的吸收积累量随土壤中Pb含量的增加而增加,垂柳在Pb 1600处理下达到峰值,根系对Pb的吸收量为42.63mg·g-1,茎和叶也表现出类似规律。苏柳172也表现出类似的规律。两种柳树根系吸收的Pb绝大部分积累在根部。两种柳树根富集重金属元素的能力显著强于茎和叶。随着铅处理浓度的增加,两种柳树生物量、根系长度、根系表面积、根体积、根直径均持续下降。4.重金属Pb对脲酶活性有一定的抑制作用,而且浓度越高,抑制作用越明显。重金属Pb降低磷酸酶的活性,但随着处理浓度的增大,酶活性呈现波动变化趋势。土壤脱氢酶活性随着土壤重金属Pb含量的增加而提高。更多还原

【Abstract】 The study focused on ability of uptake kinetic characteristics of lead, the effect on biomass, physiology and biochemical, soil enzymes activity under lead stress. The experimental material was Salix babylonica Linn and Salix jiangsuensis CL’J172’, experimental method was hydroponic and soil culture. The main results are described as follows:1. Root length significantly decreased under lead stress. Root surface area, root volume、and average diameter of root in Salix babylonica increased under moderate lead stress, root surface area, root volume、and average diameter of root in Salix jiangsuensis CL’J172’decreased significantly exposed to lead. SOD activity, proline content and POD activity increased under moderate lead stress, but declined under extreme lead stress. Leaf soluble protein and chlorophyll content decreased under lead stress, though the trends differed for different species.2. The net concentration-dependent uptake influx of Pb in both willows were characterized by Michaelis-Menten type nonsaturating kinetic curves. The amount of lead uptake by roots of both willow species increased with lead concentration and exposed time. Root cap lead content was significantly higher than that in the mature root which suggests that the root cap was more active in the uptake of Pb.The addition of acetic and malic acids enhanced the uptake of Pb in salix roots.3. The accumulation of lead in examined salix exceeded that of contrast in a growing period. The accumulation of lead in roots increased with the increase lead concentration in the soil. At 1600mg·kg-1 Pb, roots reached maximum,being 42.63 mg·g-1. And stems and leaves reflected similar laws. The absorption of lead mainly accumulated in roots, but hardly transferred to stems and leaves. The accumulative ability of roots was larger than that of stems and leaves. The results show that biomass, root length, root surface area, root volume、and root vigor significantly decreased with the increase of Pb concentrations.4. Urease activities was depressed under lead stress. The higher the concentra-tion of Pb, the greater the effect. Phosphatase activities were depressed by Pb, though the trends differ for different Pb concentrations. Dehydrogenase activities increased with an increase of Pb concentrations.更多还原