摘要
研究了Pb在水蕴草中的积累、亚细胞分布和赋存形态,以期揭示水蕴草对Pb的耐性机制。结果表明,在9 d的水培实验中,水蕴草对Pb的富集量随着Pb处理浓度的升高而增加,最大可富集103.55 mg/g DW,可以修复较高Pb污染(<100 mg/L)的水体。通过差速离心法测定Pb在水蕴草亚细胞中的含量表明,Pb在水蕴草体内的分布规律为细胞壁>细胞器与膜>可溶性部分,其中细胞壁是Pb的主要贮存部位。采用化学试剂逐步提取法分析Pb存在的化学形态表明,水蕴草体内的Pb主要以盐酸提取态为主,其次为醋酸和氯化钠提取态,其他Pb提取态的含量则较少。而细胞壁中Pb的赋存形态主要以盐酸提取态和醋酸提取态为主,细胞器和膜中的Pb主要以氯化钠和醋酸提取态为主。综上表明,水蕴草主要通过将Pb与草酸盐和磷酸盐相结合,从而将其束缚在细胞壁中,限制了Pb进入细胞内部,从而减轻了Pb对水蕴草的毒害,增强了水蕴草对Pb的耐性。
The accumulation,subcellular distribution and chemical forms of lead（ Pb） in Elodea densa（ Planch.） Casp. were investigated in order to determine the mechanisms involved in Pb tolerance. We found that the accumulation of Pb in Elodea densa（ Planch.） Casp. increased along with the rise of Pb in sulution under different Pb solution for 9 days. Elodea densa（ Planch.） Casp. could accumulate of Pb with a maximum of103. 55 mg / g（ dry weight） after being exposed to 100 mg / L Pb,which enabled it to repair a higher contaminated water of Pb（ 100 mg / L）. According to the contents of Pb in subcellular fractions that were separated by the differential centrifugation,we determined that the distribution of Pb in Eodea densa（ Planch.） Casp. decreased as the following pattern： cell wall cell organelle and membrane soluble fraction,among which indicating that cell wall was apparently the major storage of site for Pb in the plant. Through the sequential chemical extraction method,we also determined that the Pb in Eodea densa（ Planch.） Casp. was proved to be mainly most existing soluble in the extration of HCl,followed by HAc and Na Cl,others being the least. Moreover,the chemical forms of Pb were chiefly HCl- and HAc-extractable forms in the cell wall,whereas Na Cl- and HAc-extractable forms were recovered from cell organelles and membranes. Thus,we determined that when combined with other compounds,which including oxalate and phosphate,the Pb of Elodea densa（ Planch.） Casp. was prevented from moving within the cell,and was instead bound to the cell wall,which,as a result,diminished the potential of the Pb toxicity and increased the plant＇s tolerance.
出处
《环境工程学报》
CAS
CSCD
北大核心
2016年第6期3063-3070,共8页
Chinese Journal of Environmental Engineering
关键词
水蕴草
亚细胞分布
化学形态
PB
Elodea densa（Planch.） Casp
subcellular distribution
chemical forms
lead
