Nitric Oxide Increases the Physiological and Biochemical Stability of Soybean Plants under High Temperature

• Published in: Agronomy (Basel) Vol. 9; no. 8; p. 412
• Main Authors: Vital, Roberto Gomes, Müller, Caroline, da Silva, Fábia Barbosa, Batista, Priscila Ferreira, Merchant, Andrew, Fuentes, David, Rodrigues, Arthur Almeida, Costa, Alan Carlos
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 26.07.2019
• Subjects: Acclimatization; Amino acids; antioxidant system; Antioxidants; Ascorbic acid; Cell membranes; Chlorophyll; Cultivated plants; Damage prevention; Design of experiments; Economic impact; Enzymatic activity; Enzyme activity; Experimental design; Exposure; Fluorescence; Gas exchange; Growth chambers; Heat; High temperature; Humidity; L-Ascorbate peroxidase; Lipid peroxidation; Lipids; Metabolism; Metabolites; Nitric oxide; Organic compounds; Peroxidase; Peroxidation; Photochemicals; Photosynthesis; photosynthetic efficiency; Photosynthetic pigments; Photosystem II; Physiological effects; Physiology; Pigments; Plant growth; Potassium; Sodium nitroprusside; Soil temperature; soybean; Soybeans; Substrates; Temperature effects; Thermal stress; thermo tolerance; Brazil; United States > US; Germany
• ISSN: 2073-4395; 2073-4395
• DOI: 10.3390/agronomy9080412

Thermal stress reduces plant growth and development, resulting in considerable economic losses in crops such as soybeans. Nitric oxide (NO) in plants is associated with tolerance to various abiotic stresses. Nevertheless, there are few studies of the range of observed effects of NO in modulating physiological and metabolic functions in soybean plants under high temperature. In the present study, we investigated the effects of sodium nitroprusside (SNP, NO donor), on anatomical, physiological, biochemical, and metabolic processes of soybean plants exposed to high temperature. Soybean plants were grown in soil: sand (2:1) substrate in acclimatized growth chambers. At developmental V3 stage, plants were exposed to two temperatures (25 °C and 40 °C) and SNP (0 and 100 μM), in a randomized block experimental design, with five replicates. After six days, we quantified NO concentration, leaf anatomy, gas exchange, chlorophyll a fluorescence, photosynthetic pigments, lipid peroxidation, antioxidant enzyme activity, and metabolite profiles. Higher NO concentration in soybean plants exposed to high temperature and SNP showed increased effective quantum yields of photosystem II (PSII) and photochemical dissipation, thereby maintaining the photosynthetic rate. Under high temperature, NO also promoted greater activity of ascorbate peroxidase and peroxidase activity, avoiding lipid peroxidation of cell membranes, in addition to regulating amino acid and organic compound levels. These results suggest that NO prevented damage caused by high temperature in soybean plants, illustrating the potential to mitigate thermal stress in cultivated plants.