Photosynthesis, photorespiration and productivity of wheat genotypes (Triticum L.)

Abstract

The results of the numerous measurements obtained during the last 40 years on gas exchange intensity using of infrared gas analyzer URAS-2T (Germany), photosynthetic carbon metabolism by exposition in 14CO2 and activities of enzyme of primary carbon fixation, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPC/O) in various wheat genotypes grown over a wide area in sowings and contrasting on photosynthetic traits and productivity are presented in this paper. It was established that high productive wheat genotypes with the best architectonics (7—9 t ha−1) possess higher intensity of CO2 assimilation and high values of photorespiration in leaf ontogenesis. Genotypes with moderate (4–5 t ha−1) and low (3 t ha−1) grain yield are characterized by relatively low intensity both of CO2 assimilation and photorespiration. Activities of RuBP carboxylase and RuBP oxygenase were changing in a similar way in the course of the flag leaf and ear elements development. The rates of sucrose (the main transport metabolite in plants) biosynthesis and products of glycolate metabolism also correlate with the CO2 assimilation rate and the activity of RuBP oxygenase. Hence, taking into account the versatile investigations on different aspects of photorespiration it was proved that photorespiration is one of the evolutionary developed vital metabolic processes in plants.