Changes in chlorophyll content in wheat leaves when changing the water regime

Background. The pigment composition of plants is an indicator that determines the work of the photosynthetic apparatus of plants. The quantitative content of photosynthetic pigments during the growing season is a dynamically changing indicator. The purpose of the research was to study the content of chlorophyll and the strength of its bond with the proteinlipid complex in the leaves of various varieties of winter wheat under various moisture conditions. Materials and methods. The varieties of winter soft wheat zoned in the Republic of Dagestan were studied: Grom, Vassa, Bezostaya 1 (control). The experiments were carried out in two variants: I – cultivation of varieties with soil moisture of 80% PV; II–cultivation of varieties with soil moisture of 30% PV. Results. The content of total chlorophyll varied under conditions of insufficient moisture (30% PV) in the tube exit phase from 10.18 (Thunder) to 11.44 (Wassa) mg/g of dry matter. The increase in the total chlorophyll content in the developmental phase in the experiment of 30% humidification compared with the control (Non-stop 1) was 3.6% and 4.1% (Vassa). The level of strongly bound chlorophyll in the leaves of varieties in the experiment of 30% PV ranged from 3.78 (Thunder) to 10.67 (Wassa) mg/g of dry matter, and in the 80% PV variant, respectively, from 1,73 (Non-stop 1) to 10.35 (Wassa) mg/g of dry matter. The residual water deficiency of the leaves of the varieties varied under conditions of insufficient moisture (30 %) in the earing-flowering phase from 68.8% (Thunder) to 76.8% (Vassa), and under conditions of optimal moisture (80%) from 69.3% (Thunder) to 75.7% (Vassa). The leaves of the Vassa variety were the most resistant to moisture loss in all phases of plant development. The leaves of the Grom variety are the least stable. The increase in the water retention capacity of leaves in the experience of insufficient moisture (30%) compared with the control (Non-stop 1) was 17.4% (Vassa) in the grain filling phase. The increase in the content of strongly bound chlorophyll compared with the control (Nonstop 1) in all phases was shown by the Vassa variety. The largest increase in the content of the degree of ordered water in the experiment by 30% compared with the control (Non-stop 1) was shown by the Grom variety in the grain filling phase (16.1%), followed by the Vassa variety (13.8%). Conclusions. The Vassa variety shows the greatest resistance to lack of moisture. The leaves of plants of this variety, grown at 30% soil moisture, are characterized by a high water retention capacity, a high content of an ordered fraction of water, a good ability to resist dehydration compared with the control (Bezostaya 1) and the Grom variety.