Influence of abiotic factors on photosynthesis and production process of different winter wheat varieties

Abstract

Aim. The investigation of photosynthesis and production process in winter wheat varieties, different in their grain productivity, its connection to the active surface area of the root system in optimal conditions, under drought and mineral nutrition defi ciency. Methods. Physiological, biochemical, gas exchange analysis, statisti- cal methods. Results. It was demonstrated that different conditions of mineral nutrition and soil drought have impact on the intensity of photosynthesis, photo- and dark respiration, the content of pigments in the fl ag leaf of winter wheat plants; the results obtained testify to the interrelation of these indices to the active surface area of the root system and grain productivity of winter wheat varieties, different in potential grain productivity. Conclusions. It was determined that under drought the photosynthetic apparatus of a highly productive winter wheat variety Smuhlianka demonstrated higher stability compared to the photosynthetic apparatus of the vari- ety Myronivska 808, moderately resistant to drought conditions. At the same time, highly intensive varieties of winter wheat, Favorytka and Smuhlianka, had a larger active surface area of the root system and chlorophyll content in leaves, compared to Myronivska 808 plants, notable for their lower grain productivity. It was deter- mined that there was considerable reliable correlation between the intensity of fl ag leaf photorespiration and the active surface area of the root system in winter wheat plants of varieties Myronivska 808 and Smuhlianka (r = 0.805). Considerable correlation (r = 0.878) was found between the intensity of fl ag leaf photorespiration in the heading-blossoming phase and the sum of chlorophylls in these leaves. It was determined that the index S r act × chlorophyll may be used to estimate the active surface area of the root system with the error of up to 3.8 % for fi ve winter wheat varieties.