Changes in activities and levels of pyruvate, orthophosphate dikinase with induction of Crassulacean acid metabolism in mesembryanthemum crystallinum L.

Abstract

In Mesembryanthetnum crystallinum L.leaves exhibiting C3 photosynthesis, Crassulacean acid metabolism (CAM), as characterized by CO2 uptake during the dark period, was induced by exposing the plant roots to high NaCl concentration over a week. The increase in malate content in the leaves at the end of the dark period correlated with the increases in the activities of phosphoenolpyruvate carboxylase (PEPCase), NADP malic enzyme (NADP-ME) and pyruvate, orthophosphate dikinase (PPDK) which exhibited a maximum about a week after NaCl treatment. It was found that PPDK existed in C3-M. ctystallinum and the increases in the activities of PEPCase and PPDK were accompanied by the de novo synthesis of these proteins