Changes in donor-acceptor relations and leaf photosynthesis activity as a result of buckwheat plant selection for seed productivity

The article presents the results of many years of research on the study of donor-acceptor relations in buckwheat varieties of different selection periods. The purpose of the research is to study the role of donor-acceptor relations between the organs of buckwheat plants in changing the activity and efficiency of photosynthesis in connection with selection for seed productivity. The objects of research were varietal samples of culture of different periods of selection. The studies have shown that in plants, most (57.9%) of dry matter is spent on the stem, side shoots and leaves, and only 25.9% on fruit formation. It has been established that as a result of artificial selection, the intensity of photosynthesis of buckwheat plant leaves increases significantly, mainly during the formation and filling of seeds, when the demand for photoassimilates increases sharply. Modern crop varieties in the "flowering + 10 days" phase exceed the intensity of leaf photosynthesis of old varieties and local populations by an average of 8.3%, and in the "flowering + 20 days" phase by 20.3%. The results of model field experiments on the study of photosynthetic load on different plant leaves have shown that these mechanisms are well developed in buckwheat. In particular, the removal of a certain number of leaves from plants in different layers (while preserving inflorescences) led to an increase in the photosynthesis activity of the remaining leaves on average: the leaves of the main stem - by 17.1%; the leaves of the lateral shoots - by 10%, the leaves of the generative sphere - by 11.5%. Whereas, when generative organs were removed from plants in the "flowering +30 days" phase, the intensity of leaf photosynthesis, on the contrary, decreased by an average of 68.1%, compared with intact plants. That is, the influence of the attenuating centers (generative organs) on the photoactivity of the leaves is significantly higher than their interaction with each other. It is concluded that the creation of varieties with a high harvesting index is the most reliable way to intensify photosynthesis at the genetic level.