Physiological and biochemical features of drought resistance of potato plants

Abstract

The purpose of the study is to identify the relationship between drought resistance indicators and the yield of potato plants under unfavorable conditions. A xeromorphic leaf structure is considered a diagnostic sign of plant drought resistance. The objects of the study were 24 potato varieties. Planting of seed, pre-planting tillage, harvesting and crop recording were carried out in the period 2020-2022 on the territory of the Samara Research Institute of Agriculture - a branch of the Samara Scientific Center of the Russian Academy of Sciences. Growing conditions for 2021 and 2022 characterized by elevated temperatures and insufficient moisture. The number and size of stomata per unit leaf area were chosen as the criterion for xeromorphism. The studied varieties were divided into two groups (n=12 each) according to the number of stomata. In the first group, the average number of stomata was 26 thousand pcs./cm2 of leaf, and in the second group - 35 thousand pcs. (F=41, p=0.03). More developed structural features of xeromorphism and the accumulation of certain types of metabolites in the second group of varieties led to a 1.6 times greater yield than in the first less xeromorphic group (F=9, p=0.004). The second group was characterized by a large number of mesophyll cells per unit leaf area (584 thousand pieces/cm2 versus 557 thousand pieces), a high content of phospholipids (36 mg/g dry weight versus 31 mg/g), dry weight (0.19 vs. 0.17 g/g wet weight) and the ratio of membrane lipids to membrane proteins (1.4 vs. 1.2). In the less xeromorphic group of plants, the level of oxidative stress, assessed by LPO products, was 0.050 µM/g fresh weight and was 12 % higher than in the more xeromorphic group (F=6, p=0.08). The revealed positive correlation between yield and xeromorphic genotypes indicates the prospects of using this criterion in potato breeding or creating a variety model.