水培茶树对铅的吸收与累积特性研究

添加铅盐进行水培茶树试验,用火焰原子吸收光度法测定铅含量,研究茶树对铅的吸收、累积及分布特性。结果表明,铅离子能被根系或叶片大量吸收和累积,并按浓度差通过茎段转运与再分布;根施或叶部喷施2500mg/L的铅盐溶液,根系铅含量分别为8.00×10⁴mg/kg和8.38×10³mg/kg,叶片铅含量分别为551.79mg/kg和1.03×10⁴mg/kg,两者的铅富集量很高,但仍未见茶树死亡;当铅盐质量浓度为800~2000mg/L时,茶树逐渐受到铅危害,早期吸收根转为透明状,再褐变,后期叶片部分脱落;当铅盐质量浓度为300~800mg/L,水培茶树35d,茶树长势良好,未见受害症状。研究表明,水培茶树对铅具有大量吸收与累积的能力,并对铅危害有很强的抵抗与耐受力。

Uptake and Accumulation Characters of Lead in Tea Plants (Camellia sinensis) Grown in Hydroponics

Lead(Pb) concentration was investigated in tea plants(Camellia sinensis) grown in hydroponics by the FAAS method to understand the Pb uptake,accumulation and distribution characters in tea plants.The results showed that Pb ion can be uptaken and accumulated by roots in a large quantity,transported through stems along with concentration gradient,and redistributed.Cultured in 2500 mg/L Pb solution or sprayed the same solution on leaves(cultured in distilled water),Pb concentration in roots were 8.00×104 mg/kg and 8.38×103 mg/kg,respectively,in leaves were 551.79 mg/kg and 1.03×104 mg/kg respectively.Even such high accumulation the tea plants were still alived.At the range of 800～2000 mg/L Pb solution,tea plants were gradually damaged;in the early time,absorbing roots became transparent,and then turned brown,and leaves were defoliated in the latter period.Tea plant cultured under the 300～800 mg/L Pb solution for 35 d,these plants grew well,and no damaged symptoms can be observed.Results indicated that tea plants possessed a strong ability of Pb uptake,accumulation and tolerance.