Lead and Cadmium Absorption and Accumulation in Tobacco at Different Growth Stages

Abstract

A pot culture experiment on FCT and BT treated with different rates of Cd and Pb was carried out,the contents of Cd and Pb in tobacco leaves at rosette stage(RS),late fast growing stage(LFGS),beginning flowering stage(BFS) and full flowering stage(FFS) were determined and the difference between FCT and BT was analyzed.The results showed that: 1) the Pb content in FCT and BT leaves reduced continuously from RS to BFS,while it increased from BFS to FFS,which was a sensitive stage for Pb Absorbing of FCT and BT.The Pb and Cd application would change Pb Absorption and accumulation dynamically, and bring about another sensitive stage(from transplant to RS);2) Cd content in FCT leaves reduced continuously from RS to BFS,while it increased from BFS to FFS,which was a sensitive stage for Cd Absorbing of FCT;3) Cd content in BT leaves without Pb and Cd application reduced continuously from RS to BFS,while it increased from BFS to FFS.As for BT applied with Pb and Cd,Cd content increased from RS to LFGS,decreased from LFGS to BFS,and raised again from BFS to FFS.The sensitive stage for Cd Absorbing of BT without Pb and Cd application was from BFS to FFS,while for BT applied with Pb and Cd,there are two sensitive stages,which were from RS to LFGS and from BFS to FFS respectively; 4) both FCT and BT had better Absorbing ability to Cd than that to Pb,and Cd and Pb application intensified the difference,however,the difference was not obvious in BT at RS.