Phosphoenolpyruvate carboxylase isolated from Panicům maximum Jacq. leaf presented a hysteretic behaviour that resulted in a kinetical lag in the reaction progress curve. This lag depended on the concentration of etuiyme, total phosphoenolpyruvate (PEP) and total Mg2+. Through an analysis of these dependences it is suggested that the hysteresis is due to an association-dissociation process influenced by union, to one form of the enzyme, of more than one of the three possible ligands; free Mg2+, free PEP or PEP-Mg2+ complex. The partially purified enzyme showed, during steady statě, a Michaelis-Menten kinetics for PEP and Mg2+ (total concentrations) and pH optima between 7.8 and 8.2.
In the present study, photosynthetic traits and chlorophyll (Chl) fluorescence parameters of Populus sibirica grown under different irrigation regimes were investigated to estimate seedling growth and vitality for reforestation of a desertification area. According to our results, photosynthesis and Chl fluorescence were significantly affected by water deficit only under severe drought conditions., T. Y. Lee, S. Y. Woo, M. J. Kwak, K. Inkyin, K. E. Lee, J. H. Jang, I. R. Kim., and Obsahuje seznam literatury
Carbonic anhydrase (CA) activity and net photosynthetic rate (/’N) in the leaves, and plant dry mass (DM) in twelve cultivars of mustard (Brassica juncea L.) were measured 50, 70 and 90 d after sowing. At different sampling stages CA was strongly associated with PN and DM.