THE CAM-SPECIFIC ISOFORM OF PHOSPHOENOLPYRUVATE CARBOXYLASE FROM MESEMBRYANTHEMUM-CRYSTALLINUM IS A STABLE-MOLECULE

After rewatering salt-stressed M. crystallinum plants that contained h igh amounts of phosphoenolpyruvate carboxylase (PEPC) protein and corr esponding mRNA, the leaves' water content increased. The messenger RNA for PEPC decreased rapidly with a half-life of less than 24 h, wherea s the PEPC protein, PEPC enzymic activity and CAM, as measured by noct urnal acid accumulation, had several days' half-lives.