The role of various organs of the wheat plant in photosynthesis

The characteristics of CO2 assimilation were studied in photosynthesizing organs of wheat varieties with contrasting morphophysiological characteristics during ontogenesis in different irrigation regimes. The maximum values of the total amount of assimilated CO2 in both studied varieties and both variants were observed in the phase of grain formation, and the minimum values were detected in the phase of wax ripeness. In the initial phases, leaves had a greater share of CO2 assimilation. Towards the end of vegetation, the role of leaves in photosynthesis decreased, and the role of organs such as the leaf sheath, the spike base, and the spike increased. In both varieties, the total amount of CO2 assimilated by phases decreased more in the drought variant. The photosynthesis of other organs along with leaves was found to be also important in the process of grain-filling, especially under drought conditions.