钾调节茎用芥菜同化物运输及茎部膨大的作用机理

STUDIES ON MECHANISM OF THE ACTION OF POTASSIUM ON THE ASSIMILATE TRANSPORT AND STEM ESPAND OF STEM MUSTARD (BRASSICA JUNCEA CASS VAR. TUMIDA TSEN ET LEE

The effect of potassium on the assimilate.transport of stem mustard cultivars was studied with field test and pot experiment by measuring the activity of SPS,invertase,ATPase and the export rate of ~(14)C-assi-milate of leaves. The results showed that the export rate of assimilate of leaves was accelerated by potassium and the more assimilate was distributed to the harvest organ-expaneing stem. Potassium depressedthe activity of acid invertase significantly, but unaffected the neutral invertase. The SPS activity of leaf was evidently increase and more sucrose were synthesized by higher potassium treatment. The ATPase activity, especially ATPase of plasmalemma was significantly increased in leaves of stem mustard by higher potassium treatment. In normal potassium concentrations, the activity of ATPase of plasmalemma was corresponding to the potassium contents in leaves.The ATPase activity of plasmalemma was increaseed 39.8% by exogenous 50mml K~+ in reaction mixture. The electrograph of ATPase activity in the leaf cells of stem mustard showed that the ATPase activity was located at plasma-lemma, vacuolar membrane, plasmodesma, nucleus, chloroplast, mitochondria and cell wall. The activity of ATPase of leaf in higher potassium treatment was higher than in lower potassium treatment. And the activity of ATPase in plasmalemma and tonoplast was higher than other parts of cell.