PHOTOSYNTHETIC ENZYMES OF WHEAT GENOTYPES DIFFERING IN PRODUCTIVITY

Activities of carbonic anhydrase, ribulose-1,5-bisphosphate carboxylas e (RuBPC) and ribulose-1,5-bisphosphate oxygenase (RuBPO) were changin g in a similar way during the leaf development but with individual gen otypes at the same developmental phase the RuBPC/RuBPO activities rati o was stable. The ear of an intensive wheat cultivar had higher activi ty of these enzymes than that of an extensive cultivar. During grain m aturation the period of a significant increase in the RuBPC activity i n the glume of both the intensive and extensive genotypes coincided wi th that of a decrease in its activity in the flag leaf, and hence the photosynthetic activity of the elements of the ear and of the glume in particular played a significant role in the process of grain maturati on. A close positive correlation was found between the activity of the se enzymes and the productivity of wheat genotypes. Exogenous applicat ion of carbonic anhydrase stimulated the RuBPC activity, and thus the role of plant carbonic anhydrase was to accelerate the HCO3- dehydrati on reaction, increase the CO2 concentration in places of carboxylation , and thereby make the activity of RuBPC in a cell more effective.