【摘要】 通过田间调查及盆栽试验,探讨砷、镉元素在茶树中的分布规律及吸收累积特性。结果表明,砷、镉元素在茶树体内活性较低,大部分被吸收根固定,向地上部运输的比例较低。正常状况下,砷、镉元素在茶树体内由高到低的分布次序是:吸收根>茎(生产枝)或主根>老叶(当年生成熟叶)>新梢(1芽2叶)。茶树受砷、镉污染时,吸收根对阻止土壤砷、镉向新梢转移起到明显的缓冲及屏障作用。当镉添加量为6 mg.kg-1时,茶树的叶绿素含量开始受到显著的负面影响,但光合速率、蒸腾速率及气孔导度变化不明显;当镉添加量为20 mg.kg-1时,上述4项指标均显著降低。砷添加量为50 mg.kg-1时,对茶树光合速率、蒸腾速率及气孔导度产生显著负面影响,但对叶绿素含量的影响不明显;砷添加量为200 mg.kg-1时,则对光合速率、蒸腾速率及气孔导度无显著影响。更多还原

【Abstract】 Through field investigations and pot trials,it was found that As and Cd was low in mobility in tea plant.Most of the As and Cd absorbed by the plant is fixed in feeder roots and only a small amount is transported to above ground parts.Distribution of As and Cd,based on their concentrations per unit dry matter,in tea plants growing on un-contaminated soil,is in the order as feeder roots>stems or main roots>old leaves>young leaves.When tea plants were growing on polluted soils,simulated by addition of salts of these two metals,feeder roots possibly acted as both buffer and defense,inhibiting As and Cd from moving up to above ground parts.The concentration of Cd from 6 to 20 mg·kg^-1 in soil was significantly and negatively correlated with chlorophyll content,photosynthetic rate,transpiration rate and biomass production rate of tea plants,whereas the concentration of As from 50 to 200 mg·kg^-1 was first negatively,but late little correlated.更多还原