Wang Donghong, Wang Yun, Yin Yuanming, Min Shan, Wang Shaoyun, Yu Yunlong
Department of Plant Protection, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China.
Environ Sci Pollut Res Int. 2015 Apr;22(7):5437-43. doi: 10.1007/s11356-014-3757-z. Epub 2014 Oct 30.
The injury to sensitive rotational crops caused by residual herbicides from their applications has happened frequently. The assessment of activity of residual herbicide in soil has been of agronomic concern. To accurately determine the toxicity and obtain a comparable concentration that inhibits growth by 50% (IC50) in different soils, the concentrations of imazaquin in CaCl2 (CCaCl2) and H2O (CH2O) extraction and in in situ pore water (CPW) were adopted for the estimation of IC50 to sorghum. The IC50 values based on CCaCl2 and CH2O were 0.06 mg L(-1) in soil Ansai (AS) to 0.13 mg L(-1) in soil Huajiachi (HJC), 0.32 mg L(-1) in soil AS to 0.71 mg L(-1) in soil HJC, respectively, with variation coefficients of 38.32 and 34.93%. However, CPW-based IC50 values ranged from 0.90 mg L(-1) in soil Xiaoshan (XS) to 1.09 mg L(-1) in soil HJC with a variation coefficient of 6.96%. This implies that the IC50 based on imazaquin concentration in in situ pore water is almost identical in the five soils. With further studies with more herbicides and plant species, this method might be expanded for the estimation of phytotoxicity of residual herbicide(s) to plant(s).
除草剂施用后残留药剂对敏感轮作作物造成的伤害屡见不鲜。土壤中残留除草剂活性的评估一直是农学关注的问题。为准确测定毒性并获得不同土壤中抑制生长50%（IC50）的可比浓度，采用在CaCl2（CCaCl2）和H2O（CH2O）提取液以及原位孔隙水中的咪草喹浓度来估算对高粱的IC50。基于CCaCl2和CH2O的IC50值在安塞土壤（AS）中为0.06 mg L(-1)至华家池土壤（HJC）中的0.13 mg L(-1)，在AS土壤中为0.32 mg L(-1)至HJC土壤中的0.71 mg L(-1)，变异系数分别为38.32%和34.93%。然而，基于原位孔隙水的IC50值范围从萧山土壤（XS）中的0.90 mg L(-1)至HJC土壤中的1.09 mg L(-1)，变异系数为6.96%。这意味着基于原位孔隙水中咪草喹浓度的IC50在这五种土壤中几乎相同。随着对更多除草剂和植物种类的进一步研究，该方法可能会扩展用于估算残留除草剂对植物的植物毒性。
