The effects of 5 mg/L 1,2,4-trichlorobenzene （TCB） and 0.1 mmol/L mercury ion （Hg^2＋） stresses on Ca^2＋ fluxion and protein phosphorylation in rice seedlings were investigated by isotope exchange kinetics and in...The effects of 5 mg/L 1,2,4-trichlorobenzene （TCB） and 0.1 mmol/L mercury ion （Hg^2＋） stresses on Ca^2＋ fluxion and protein phosphorylation in rice seedlings were investigated by isotope exchange kinetics and in vitro phosphorylation assay. The Ca^2＋ absorption in rice leaves and Ca^2＋ transportation from roots to leaves were promoted significantly in response to Hg^2＋ and TCB treatments for 4-48 h. The Ca^2＋ absorption peaks presented in the leaves when the rice seedlings were exposed to Hg^2＋ for 8-12 h or to TCB for 12-24 h. Several Ca^2＋ absorption peaks presented in the roots during rice seedlings being exposed to Hg^2＋ and TCB, and the first Ca^2＋ absorption peak was at 8 h after being exposed to Hg^2＋ and TCB The result of isotope exchange kinetic analysis confirmed that short-term （8 h） Hg^2＋ and TCB stresses caused Ca^2＋ channels or pumps located on plasmalemma to open transiently. The phosphorylation assay showed that short-term TCB stress enhanced protein phosphorylation in rice roots （TCB treatment for 4-8 h） and leaves （TCB treatment for 4-24 h）, and short-term （4-8 h） Hg^2＋ stress also enhanced protein phosphorylation in rice leaves. The enhancement of protein phosphorylation in both roots and leaves corresponded with the first Ca^2＋ absorption peak, which confirmed that the enhancement of protein phosphorylation caused by TCB or Hg^2＋ stress might be partly triggered by the increases of cytosolic calcium. TCB treatment over 12 h inhibited protein phosphorylation in rice roots, which might be partly due to that TCB stress suppressed the protein kinase activity. Whereas, Hg^2＋ treatment inhibited protein phosphorylation in rice roots, and Hg^2＋ treatment over 12 h inhibited protein phosphorylation in rice leaves. This might be attributed to that not only the protein kinase activity, but also the expressions of phosphorylation proteins were restrained by Hg^2＋ stress.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.30300026).
文摘The effects of 5 mg/L 1,2,4-trichlorobenzene （TCB） and 0.1 mmol/L mercury ion （Hg^2＋） stresses on Ca^2＋ fluxion and protein phosphorylation in rice seedlings were investigated by isotope exchange kinetics and in vitro phosphorylation assay. The Ca^2＋ absorption in rice leaves and Ca^2＋ transportation from roots to leaves were promoted significantly in response to Hg^2＋ and TCB treatments for 4-48 h. The Ca^2＋ absorption peaks presented in the leaves when the rice seedlings were exposed to Hg^2＋ for 8-12 h or to TCB for 12-24 h. Several Ca^2＋ absorption peaks presented in the roots during rice seedlings being exposed to Hg^2＋ and TCB, and the first Ca^2＋ absorption peak was at 8 h after being exposed to Hg^2＋ and TCB The result of isotope exchange kinetic analysis confirmed that short-term （8 h） Hg^2＋ and TCB stresses caused Ca^2＋ channels or pumps located on plasmalemma to open transiently. The phosphorylation assay showed that short-term TCB stress enhanced protein phosphorylation in rice roots （TCB treatment for 4-8 h） and leaves （TCB treatment for 4-24 h）, and short-term （4-8 h） Hg^2＋ stress also enhanced protein phosphorylation in rice leaves. The enhancement of protein phosphorylation in both roots and leaves corresponded with the first Ca^2＋ absorption peak, which confirmed that the enhancement of protein phosphorylation caused by TCB or Hg^2＋ stress might be partly triggered by the increases of cytosolic calcium. TCB treatment over 12 h inhibited protein phosphorylation in rice roots, which might be partly due to that TCB stress suppressed the protein kinase activity. Whereas, Hg^2＋ treatment inhibited protein phosphorylation in rice roots, and Hg^2＋ treatment over 12 h inhibited protein phosphorylation in rice leaves. This might be attributed to that not only the protein kinase activity, but also the expressions of phosphorylation proteins were restrained by Hg^2＋ stress.
