【作者】 纳明亮；

【导师】 张建新；

【作者基本信息】 西北农林科技大学 ， 食品科学， 2007， 硕士

【摘要】 本文以3种典型土壤,黄泥土,褐土,红壤为供试土壤,研究了不同浓度Cu、Zn、Pb以及其在老化条件下对小白菜、包菜、萝卜、洋葱、番茄和黄瓜的早期根伸长,以阐明不同重金属及用量对蔬菜根生长的抑制及毒性效应。研究表明:黄泥土上,番茄对Cu、Zn、Pb的毒性响应最敏感,小白菜则最不敏感;红壤上番茄和小白菜对Cu、Zn、Pb的毒性响应最敏感,黄瓜和萝卜则最不敏感;褐土上,洋葱对Cu、Zn、Pb的毒性响应最敏感,黄瓜则不敏感。不同重金属对蔬菜生长抑制不同,蔬菜对铜的毒性响应最敏感,其次是锌和铅。土壤中重金属有效态与蔬菜根长呈显著负相关,对3种土壤比较得出相同Cu、Zn、Pb浓度下,重金属对番茄和小白菜的根伸长抑制率大小顺序为:红壤>黄棕壤>褐土。重金属老化时间的不同,其对蔬菜根长的影响不同,但随着老化时间的延长,其根长有增加趋势。种植蔬菜的土壤中有效态重金属含量随着土壤中加入重金属浓度的增加而增大。土壤中重金属老化趋势因其浓度的不同而异,高浓度时,在0~30d老化迅速,且达到平稳老化的时间就越长。不同老化时间对蔬菜的毒性作用2d最强,180d最弱,可见随着重金属在土壤中的老化时间延长,其对蔬菜的毒性就会降低。土壤中重金属有效态与蔬菜吸收重金属的量呈极显著正相关(rCu=0.952**, rZn=0.998**),在受重金属污染的土壤上施加石灰,能有效地降低土壤中重金属有效态含量,提高蔬菜的生物量,减少蔬菜对重金属的吸收(Cu100 ,Cu400 mg?kg-1时,施加石灰后小白菜中Cu的全量分别下降了61.1%,55.0%;Zn250,Zn500 mg?kg-1时,施加石灰后小白菜中Zn的全量分别下降了82.4%,87.6%),尤其在重金属污染土壤二级水平下,施加石灰能够使得蔬菜中的重金属含量符合蔬菜卫生标准,确保蔬菜食用的安全性。从根伸长试验得出了不同土壤上对重金属敏感的指示蔬菜,及不同种类蔬菜对Cu、Zn、Pb的EC10,EC50,EC90值。EC10值可以作为蔬菜能够正常生长的临界值,低于EC10,蔬菜基本能正常生长;EC90值可以作为蔬菜受重金属毒害致死的临界值,超过EC90,蔬菜几乎不能生长,为确保蔬菜的安全生产提供了科学依据。更多还原

【Abstract】 Three classical soils,paddy soil, brown soil and red soil are adopted to study the root elongation of pakchoi and cabbage, radish and onion, tomato and cucumber in different concentration of Cu, Zn, Pb ,and to demonstrate the toxicity and inhibition of vegetable root in different dose of heavy metal .As the study shows, tomato is the most sensitive to Cu, Zn, Pb in paddy soil, and pakchoi was insensible. Tomato and pakchoi are both the most sensitive to Cu, Zn, Pb, to the contrary, cucumber and radish are the least sensitive in red soil.. Onion is is the most sensitive to Cu, Zn, Pb, while cucumber is not sensitive in brown soil .Different heavy metal inhibits vegetable growth differently , Cu is the most sensitive, Zn、Pb are infer. A significantly negative relationship was found between root elongation and available concentration of heavy metal in the involved soil, which shows the heavy metal concentration is important factor as for inhibiting vegetable elongation. After being compared among three soils at the same concentration level, the sequence of inhibition ratio of heavy metal to tomato and pakchoi elongation is as fellows: red soil is the most sensitive, paddy soil the next, brown soil the last.Heavy metal affects vegetable differently due to different heavy metal’s aging time, with time prolonging, vegetable’s elongation tends to increase, while heavy metal inhibits vegetable less and less. The account of heavy metal in the soil planting vegetable increaseswhen adding more into the soil, which means when the aging time for heavy metal in soil prolongs, the efficiency of heavy metal will descend. The heavy metal aging tendency is different at different concentration level. The bigger the concentration is, the quicker its aging velocity becomes within 30 days, and the time it reaches steady aging time becomes longer. Different aging time shows distinct toxic effect, it is the most toxiferous on the second day ,and the least toxiferous on the 180th day, which displays when the aging time for the heavy metal in soil becomes longer, its toxicity will descend.A most significantly relationship was found between available metal in the involved soil and heavy metal absorbed by plan(trCu=0.952**, rZn=0.998** ). I t can cut down concentration of heavy metal and improve vegetable biomass, lower the absorption of heavy metal when appendding lime in soil which had polluted by heavy metal(the total content of Cu descend 61.1%,55% at Cu100 ,Cu400 mg?kg-1; when the concentration of Zn in soil at 250,500 mg?kg-1,the total content of Zn descend 82.4%,87.6% ).Especially,it can make the content of heavy metal accord with the sanitation standard of vegetables when we add lime into soil polluted by heavy metal under the two level.So we adds lime into soil polluted by heavy metal in order to better the polluted soil, reduce its poison and ensure vegetable safety.The paper gets sensitive indicating plant for different soil by elongation experiment, and gets EC10,EC50 and EC90 to Cu、Zn、Pb for every vegetable. EC10 can be treated as physeal critical value for vegetable normal growth, if the index is inferior to EC10, the vegetable basically keeps normal growth. Meanwhile, EC90 is the critical value for vegetable′s being poisoned to death, if the index is above EC90 , the vegetable nearly can’t vegetate.,which supply us foundation for vegetable safety production.更多还原