Changes in Some Photosynthesis Indicators Under Different Donor-Acceptor Relations of Wheat Under the Influence of Drought

The results of studies of changes in some parameters of photosynthesis - the formation of leaf surface and the area of ​​other assimilating organs, the accumulation of dry above-ground biomass, chlorophyll content in the ontogenesis of wheat genotypes at different donor-acceptor relationships are presented. In the studied varieties, the dynamics of leaf surface area and the amount of increase in dry biomass during ontogenesis depend not only on the developmental phase and genotypic characteristics of the plants, but also on the state of donor-acceptor relationships in the whole plant system, as well as on the influence of drought. In all studied varieties, when half the ear was removed under both conditions, an increase in the area and dry biomass of stems and leaves was observed. With a decrease in the attracting ability of the ear, it needs significantly less leaf photosynthesis products and the remainder of the assimilates is spent on increasing the area of ​​the leaves themselves. At the same time, changes in donor-acceptor relationships affect the chlorophyll content in leaves. In all cases, the removal of leaves of the 7th tier leads to an increase in the chlorophyll content in the leaves of the 8th tier and vice versa. When half of the ear is removed, the chlorophyll content of both leaves of the 7th and 8th tiers decreases significantly.