土壤铜植物毒害的不同评价终点和室内外测定差别研究

本论文对山东陵县、湖南祁阳和浙江嘉兴3种性质差异较大的土壤上进行的室内外的土壤外源铜(Cu)的植物毒性试验结果进行了比较。结果发现3种室内评价终点(大麦根长、西红柿和小白菜苗期生物量)和田间植物(玉米、小麦、水稻和油菜产量)对土壤中Cu毒性的敏感性存在较大的差异。大麦根伸长和小白菜生物量法高估了土壤中Cu对田间小麦、玉米和水稻产量的毒害,而室内西红柿生物量法则低估了土壤中Cu对田间小麦、玉米和水稻产量的毒害。小白菜和田间油菜的敏感性接近,可以用室内小白菜苗期生物量作为土壤中Cu对田间油菜产量毒性评价的植物。当采用相同植物比较时,陵县小麦、祁阳玉米和嘉兴油菜的室内苗期值可以作为土壤Cu对相同田间植物产量的毒害作用(EC_(10))的评价指标。但是,室内苗期毒害指标会低估Cu对田间祁阳小麦和高估嘉兴水稻的毒害作用,说明土壤Cu植物毒害室内外测定的差别受土壤和植物的影响。

Differences between Laboratory and Field Tests for Phytotoxicity of Copper in Soils Using Different Assessment Endpoints

In this paper, field experiments were conducted to study the phytotoxicity of added copper (Cu) to local main crops in three field sites with contrasting soil physicochemical properties. Meanwhile, the phytotoxicity of corresponding soil samples were also measured using laboratory bioassays (barley root elongation, tomato, bok choy and local main crops seedling stage biomass). The results indicated that the phytotoxicity of Cu to field wheat, maize and rice was overestimated by laboratory bioassays of barley root elongation and bok choy biomass but was underestimated by tomato biomass. The similar sensitivity of field rape and bok choy suggested that the bok choy biomass in laboratory testing may be a suitable method to assess the toxicity of Cu to rape yield in field. When laboratory bioassays and field tests were conducted by using same plants, the seedling stage biomass of wheat, maize and rape in the laboratory could be used to estimate the phytotoxicity of Cu to grain yields of wheat at Lingxian, maize at Qiyang and rape at Jiaxing in the field (expressed as Cu toxicity threshold values EC₁₀). However, the phytotoxicity of Cu to wheat grain yield in the field at Qiyang was underestimated but rice grain yield at Jiaxing in the field was overestimated by laboratory bioassay, which indicated the differences of the Cu phytotoxicity measured using laboratory and filed bioassay were influenced by the soil types and plant species.