INFUENCE OF DIFFERENT POTTASSIVM LEVELS ON CONTENTS OF CARBOHYDRATE PROTEIN IN CYMBIDIUM SINENSE FOLLOWING POTASSIUM STARVATION Inhibition Effect of Zn2+ on Cytosolic Pyruvate Kinase in Passiflora edulis Leaves Cloning and Expression Characterization of Gene Encoding Pyruvate Kinase from Lonicera japonica Thunb. Cloning and expression analysis of pyruvate kinase gene in Dendrobium officinale