The response of two potato cultivars on combined effects of selenium and drought

The combined effect of selenium (Se) foliar spraying and drought was studied for 3 months in two cultivars of potato; Bard and Adora in Ljubljana, Slovenia. Four combinations of treatments were conducted: well-watered plants with and without Se foliar spraying, and drought exposed plants with and without Se foliar spraying. Net photosynthesis, transpiration rate, quantum yield of photosystem II (PSII), and respiration potential measured by electron transport system activity were monitored throughout the period. After three months of treatment, leaf water potential, the number and size of leaf stomata, and tuber yield were determined. Several impacts of drought and Se application and their combinations were established, and the responses shown to be cultivar-specific. Net photosynthesis, transpiration rate, effective quantum yield of PSII, and respiratory potential were lower in drought exposed plants. Se lowered respiratory potential in the leaves in cv. Bard. The mass of the tubers in cv. Adora, and photosynthesis in cvs. Bard and Adora were lower in Se treated plants. Se treatment did not significantly affect the number and size of leaf stomata in the cultivars.