加拿大一枝黄花对土壤砷污染的生长响应

摘要

为了认识入侵植物对土壤砷污染的生长响应,进行土壤加砷种植加拿大一枝黄花的盆栽实验,观察一枝黄花的长势、测定一枝黄花的株高、茎粗和生物量.结果表明,高砷对一枝黄花具有毒害作用,其中毒症状为植株矮化,新叶发黄,叶尖焦枯,根系腐烂.与对照相比,当土壤加砷浓度不大于100 mg·kg-1时,一枝黄花的株高和茎粗无显著变化;加砷200和500 mg·kg-时,株高分别降低49.9％和89.1％,茎粗分别降低48.4％和58.3％.土壤加砷不大于50 mg·kg-1时,一枝黄花的生物量没有显著变化.土壤加砷水平达到100 mg·kg-1时,一枝黄花的根、茎、叶和总生物量均显著下降.土壤加砷水平达到500mg·kg-1时,一枝黄花根、茎、叶和总生物量降低95％以上.相关分析表明,加拿大一枝黄花的根、茎、叶生物量和总生物量均与土壤砷浓度存在显著的指数函数关系.根据指数回归方程计算得到一枝黄花根、茎、叶生物量和总生物量的半衰减浓度分别为119.2、110.3、125.3和126.1 mg·kg-1.综合来看,一枝黄花可以正常适应含砷100 mg·kg-1以下的土壤环境,但高砷环境会抑制其生长并改变其生物量的分配.%Invasive plants have strong adaptability to environment,but their adaptabilities to the contaminated soil environment are rarely reported.In order to understand the response of invasive plants to arsenic polluted soil,a pot experiment cultivating Solidago Canadensis L.(SCL) in arsenic addition soil was conducted,in which the growth of SCL was observed,and the plant height,stem diameter and biomass of SCL was measured.The results showed that high soil arsenic addition caused toxicity to SCL,and the toxic symptoms included dwarfed plants,yellow new leaves,withered leaf tips and root rot.Compared to control,arsenic additions had no significant effects on the plant height and stem diameter of SCL when arsenic concentration was no more than 100 mg · kg-1,but 200 and 500 mg · kg-1 of soil arsenic addition caused 49.9％ and 89.1％ decrease in plant height,and 48.4％ and 58.5％ decrease in stem diameter,respectively.When arsenic concentration was no more than 50 mg · kg-1,arsenic addition did not influence the biomass of SCL significantly,but caused significant decrease in the root,stem and leaf biomass of SCL at 100 mg · kg-1,and the root,stem and leaf biomass were decreased by more than 95％ at 500 mg · kg-1.The correlation analysis showed that there was a significant exponential relationship between soil arsenic additions and the root,stem and leaf biomass of SCL.Based on the exponential regression equation,the half decay arsenic concentration of the root,stem and leaf biomass of SCL was 119.2,110.3,125.3 and 126.1 mg ·kg-1,respectively.In conclusion,SCL would grow normally at no more than 100 mg· kg-1 of soil arsenic addition,but a higher concentration significantly inhibited SCL's growth and changed the allocation of its biomass among different parts of the plants.