Impact oF Hydrogen Sulfide and Nitric Oxide on Productivity, Heat Use Efficiency and Quality of Potato Tubers Under Heat Stress

The study was carried out on potato plants to assess the effects of foliar spraying with sodium hydrosulfide (NaSH) a donor of hydrogen sulfide (H2S ) at a concentration of 0, 1, 2.5, and 5.0 ml/L-1 and nitric acid (HNO3) a donor of nitric oxide ( NO ) at a concentration of 0, 1, 5.0, 7.5 and 10 ml/L-1, either separately or in combination. However The experiment was conducted during the summers of 2024 and 2025 on a private vegetable farm in Bosat Karm El-Din Village, Sherbin district, Dakahlia Governorate, Egypt.Foliar of potato plants grown in summer plantation with sodium hydrosulfide (NaSH) a donor of hydrogen sulfide (H2S) at 5 ml/l-1 and with nitric acid (HNO3) a donor of nitric oxide ( NO ) at 7.5 ml/l-1 increased vegetative growth parameters, dry weight /plant, average tuber weight , yield / plant and total yield /fed. as well as heat use efficiency , in addition, the interaction between foliar spray with NaSH (H2S - donor) at 2.5 ml/l-1 and foliar spray with HNO3 ( NO donor) at 7.5 ml/l-1 increased total chlorophyll and Superoxide dismutase enzyme (SOD) in leaves , while control treatment ( spraying with water ) increased Malondialdehyde (MDA) in leaves at 90 days after planting in both seasons . Whereas, spraying with NaSH (H2S - donor) at 5 ml/l-1 and nitric acid at 10 ml/l-1 increased dry matter (%), TSS ( Brixo), total sugars and starch content in tubers.