Effect of moisture on photosynthesis and transpiration of buckwheat leaves

¹ Orel State Agrarian University named after N.V. Parakhin, Generala Rodina str., Orel, 302019, Russia
² Federal Scientific Center of Legumes and Groat Crops, 10, Molodezhnaya St., Streletsky village, Orel region, 302502, Russia

Abstract

Currently, the issue of developing adaptive varieties of crops based on evolutionary principles is becoming urgent. The need to develop adaptive varieties for Russia is determined by the contrast of its natural and climatic conditions, global climate changes, and the increasing unpredictability of the weather. This task is highly relevant to the valuable food crop buckwheat, the yields of which are still low due to insufficient resistance of modern varieties to extreme environmental factors. Vegetation experiments to study the genotypic reaction of light and dark phases of photosynthesis of leaves on changes in soil moisture availability were carried out. During the period of buckwheat breeding from local samples to modern varieties the plants showed a significant trend in increasing the activity of photosynthesis and transpiration of plant leaves with a certain decrease in their resistance to moisture limitation. It was established that a decrease of soil moisture content from 70 to 30% of total moisture capacity caused, in modern cultivars, a mean decrease of fluorescence quantum yield by 52.5%, of electron-transport chain activity by 53.7%, of photosynthesis intensity by 66.5%, of transpiration intensity by 82.1%, whereas in local cultivars it decreased by 40.0%, 52.1%, 51.0%, and 76.1%, respectively.