四种园林植物对土壤镉污染的耐受性

采用模拟Cd污染土壤培养法,测定了Cd胁迫下山矾、桑树、绣线菊、山茶4种园林植物幼苗的生长、生物量变化,根茎叶的Cd含量,光合色素含量与MDA含量,对耐性指数(Ti)、转移系数(TF)、生物富集系数(BCF)进行了评价。结果表明:(1)山矾、桑树、绣线菊和山茶的平均耐性指数分别为93.99、82.33、82.10和87.25;(2)4个树种幼苗根茎叶的Cd含量都随着Cd处理浓度的增加而增加,转移系数值(TF)都小于1,转移能力为山矾山茶绣线菊桑树。对Cd累积能力为山矾山茶桑树绣线菊;山矾和山茶生物量吸收的Cd总量显著高于绣线菊和桑树。(3)Cd处理浓度的不断增加,叶绿素a/叶绿素b比值与对照相比变化不显著,类胡萝卜素的含量持续增加;桑树、山茶、山矾和绣线菊MDA含量分别平均上升为15%、10.17%、9.69%、12.86%。不同Cd浓度下,MDA上升幅度顺序为桑树绣线菊山茶山矾。研究表明山矾具有很高的Cd耐性、转移能力、以及地上部分积累镉的能力,是一种抗Cd污染较好的园林绿化树种。

Tolerance and accumulation of four ornamental species seedlings to soil cadmium contamination

Four kinds of ornamental plants, Symplocos caudate, Morus alba, Spiraea salicifolia, and Camellia japonica were tested under five cadmium (Cd) application rate levels that range from 0mg/kgto 100mg/kg in a greenhouse pot experiment. Effects of Cd stress on growth indexes, biomass increment, Cd content of root, stem, leaf, content of photosynthetic pigment, and content of MDA in them were investigated after one year growth. Tolerance index (Ti), Translocation factor(TF)and bio concentration factor(BCF)of 4 species are evaluated. The results showed that (1) Cd had distinct inhibition on the growth of plant, the average tolerance index of S. caudate, M. alba, S. salicifolia, and C. japonica were 93.99, 82.33, 82.10 and 87.25 separately. (2) With increasing soil Cd content, the 4 species seedlings had a increase of Cd content of root, stem and leaf. The Translocation factor of these tree species to soil Cd contamination are all lower than 1and followed the order of S.caudate > C. japonica > S. salicifolia > M. alba. BCF values of these tree species to soil Cd contamination followed the order of S. caudate > C. japonica > M. alba >S. salicifolia;The total contents of Cd absorbed in S. caudate and C. japonica are significantly higer than in S. salicifolia and M. alba. (3) Chlorophyll a/b values of them were not obviously changed compared with CK, but the contents of carotenoid of them increased with the increasing Cd concentration. The average content of MDA in M. alba, S. salicifolia, C. japonica and S. caudate increased 15%, 10.17%, 9.69% and 12.86% separately and followed the order of M. alba > S. salicifolia > C. japonica > S. caudate. The study suggested that S. caudate is a good candidate species for phytoremediation of Cd contaminated soil because of its higher Cd tolerance, transfer and accumulation ability of aboveground biomass.