Effect of chrome stress on polyamine metabolism of callus of Alternanthera philoxeroides

Callus of Alternanthera philoxeroides,as experimental material,was cultured by tissue culture technique.In this study,the calluses were subjected to different concentrations of Cr6+(0,0.1,0.3,0.6 and 0.9 mmol/L) and the impacts on contents of putrescine(Put),spermidine(Spd),spermine(Spm)and proline(Pro),activities of arginine decarboxylase(ADC),ornithine decarboxylase(ODC),polyamine oxidase(PAO) and Diamine Oxidase(DAO) were investigated.Results indicated that,with the increasing of Cr6+ concentration,(1) the contents of three free PAs increased at first and then decreased,and reached their peak values at 0.6 mmol/L Cr6+ treatments;(2) the content of PS-conjugated Put reached its peak value at 0.1 mmol/L Cr6+ treatment and then decreased slowly,while the contents of PS-conjugated spermidine(Spd) and spermine(Spm) increased significantly;(3) the peak values of PIS-conjugated Put and Spd were present at 0.6 mmol/L Cr6+ treatment;meantime the peak value of PIS-conjugated Spm was present at 0.1 mmol/L Cr6+ treatment;(4)the activities of ADC and ODC increased gradually,while PAO and DAO activities decreased sharply after a transient increase;(5) the level of Pro increased at 0.1-0.3 mmol/L Cr6+ treatments and decreased at 0.6-0.9 mmol/L Cr6+ treatments.These results suggested that Cr6+ stress disturbed metabolic balance of polyamines and increased the level of PAs.Obviously,the changes of PAs levels might be essential to Cr6+ adaption of cells.