6种陕北适生豆科植物生长对原油污染土壤的响应

Growth Responses of Six Leguminous Plants Adaptable in Northern Shaanxi to Petroleum Contaminated Soil

为筛选优良的石油污染土壤修复植物,选取陕北适生的6种豆科乡土植物,对不同浓度原油污染土壤中植物的生长差异进行研究.采用混油法盆栽试验,分设0、5 000、10 000、20 000、40 000 mg·kg-1共5个不同的原油污染浓度,分析其对土壤理化性质的改变,对植物出芽时间、出芽率、株高、植物干重、叶绿素含量和枯萎率的影响.结果表明,原油污染显著改变土壤理化性质.5 000 mg·kg-1低浓度原油污染,对受试植物的发芽率和植物株高有促进作用,后随原油浓度加大植物生长受到明显抑制.原油污染浓度低时草本植物耐受力较强,其中紫花苜蓿(Medicago sativa)在出芽时间、出芽率、株高及枯萎率等方面综合表现较优.从40 000 mg·kg-1浓度时枯萎率及叶绿素含量分析,刺槐(Robinia pseudoacacia)表现较高的耐受力.相关分析表明,原油污染浓度与植物出芽时间、出芽率、株高、干重均呈显著负相关,但与叶绿素含量呈极显著正相关.

To select appropriate native species in Northern Shaanxi for phytoremediation, the growth index of six kinds of leguminous plants planted in petroleum contaminated soils were investigated through pot culture. Petroleum concentrations were set at 0, 5 000, 10 000, 20 000, 40 000 mg. kg^-l respectively with three replicates. Using different levels of seed germination rate, germination time, individual height, wilting rate, dry weight and chlorophyll content in leaves of tested plants as the ecological indicator. The results showed that tested plants have significantly different responses to petroleum pollution. Compared with those planted in clean soils, seed germination rate and individual height were promoted when petroleum concentration was lower than 5 000 mg.kg^-1, but inhibition occurred when petroleum concentrations were higher than 10000 mg.kg^-1. Strong endurance of Medicago sativa was observed to petroleum polluted soil, especially at lower petroleum concentration. Leaf wilting of Robinia pseudoacacia was unobserved even when petroleum concentration was 40 000 mg. kg^-1 , thus displaying the potential of remediating petroleum contaminated soils. The petroleum concentration was significantly and negatively correlated with seed germination rate, individual height and dry weight, but positively correlated with chlorophyll content in leaves.