摘要
为研究无机三价砷As(Ⅲ)对生菜的生态毒性及其生物积累,采用生菜种子发芽试验和土培试验相结合的方法,从种子萌发、植株生长、生理特性以及生菜砷含量等方面研究了生菜对无机砷污染的响应。种子发芽试验表明,随着As(Ⅲ)浓度的升高,生菜种子的发芽率、发芽势逐渐减低,当As(Ⅲ)浓度高于1 mg·L-1时,显著抑制生菜种子的萌发,其抑制比例大于6.67%。土培盆栽试验表明:当土壤中添加的As(Ⅲ)浓度高于50 mg·kg-1时,生菜的株高和生物量显著低于对照组,当土壤中添加的As(Ⅲ)浓度升至200 mg·kg-1时,生菜的株高只有对照组的86.07%,地上部和地下部干重则只有对照组的72.39%和72.73%;随着土壤砷浓度的升高,生菜叶片的叶绿素含量、叶绿荧光参数和抗氧化酶活性均呈现出'低浓度促进高浓度抑制'的趋势,高浓度的砷可导致生菜叶片丙二醛含量显著升高;随着土壤砷含量的升高,生菜地上部和地下部的砷含量也明显增加,其范围分别介于0.39~2.15 mg·kg-1和1.18~2.56 mg·kg-1,当土壤砷含量高于14.98 mg·kg-1时,生菜可食用部分的砷含量超出了我国《食品卫生标准》中所规定的限值标准0.5 mg·kg-1。
Seed germination test and pot experiment were conducted to investigate the eco-toxicity and accumulation of inorganic trivalent arsenic in lettuce. The seed germination, plant growth, physiological characteristics and arsenic accumulation in lettuce were examined. The germination rates and germination potential of lettuce seeds decreased as As(Ⅲ) concentrations increased. At As(Ⅲ) concentrations greater than 1.00 mg·L-1, the seed germination was inhibited significantly, with over 6.67% reduction. In the pot experiment, plant height and biomass of lettuce were lower than those in the control when As(Ⅲ)was added to soil at more than 50.00 mg·kg-1. When As(Ⅲ)concentration was 200.00 mg·kg-1, the plant height was only 86.07% of the control, and the dry weights of the aboveground and underground parts were only 72.39% and 72.73% of the control, respectively. The chlorophyll content, leaf fluorescence parameters and antioxidant enzyme activities increased at low arsenic concentrations and then decreased at higher concentrations. High levels of soil arsenic could lead to a significant rise of malondialdehyde content in lettuce leaves. Arsenic concentrations in both aboveground and belowground parts of lettuce increased significantly with increasing soil arsenic, which were respectively 0.39~2.15 mg·kg-1and 1.18~2.56 mg·kg-1. When arsenic concentrations in soil were higher than 14.98 mg·kg-1, the arsenic concentrations detected in the edible part of lettuce would be beyond the food health standard value of 0.5 mg·kg-1.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2015年第5期831-836,共6页
Journal of Agro-Environment Science
基金
863项目(2013AA102402)
关键词
无机三价砷
生菜
生态毒理
生物积累
inorganic trivalent arsenic
lettuce
eco-toxicity
accumulation
