Studies on the Tolerance of Salix matsudana to Heavy Metals Determined by Root Elongation Method
ZHOU Jiang-li et al(School of Life Sciences,Anhui Agricultural University,Hefei,Anhui 230036)
[Objective] The research aimed to discuss the tolerance of Salix matsudana to single or compound heavy metals and provide theoretical basis for renovating polluted soil by heavy metals with woody plants.[Method] Using root elongation method,the effects of heavy metal Cu2+,Pb2+,Zn2+ and their mixed solution on the adventitious roots' growth of S.matsudana cuttings were studied.[Result] The adventitious roots' growth of S.matsudana cuttings was obviously affected by different concentrations of heavy metals solution.Adventitious roots of S.matsudana cuttings could not grow while the concentration of Cu2+ was higher than 15 mg/L,the mixture solution concentration was higher than 20 mg/L and Zn2+ concentration was higher than 30 mg/L.When the solution concentration reached 40 mg/L,adventitious roots of S.matsudana cuttings could grow only in Pb2+ treatment group.With the increasing of the solution concentration,the number of adventitious roots of S.matsudana cuttings gradually decreased.In 5 mg/L Zn2+ treatment group,the number of adventitious roots of S.matsudana cuttings was the most,the longest root length and average root length were the longest and the rooting rate was the highest.[Conclusion] The tolerance of S.matsudana to Pb2+ was strongest and its tolerance to Cu2+ was the weakest.The tolerance order of S.matsudana to three kinds of heavy metals and their mixed solution was as following: Pb2+ Zn2+ Cu2++Pb2++Zn2+ Cu2+.