Abstract:
Objective To investigate whether β-aminobutyric acid (BABA) could protect Rhododendron from NaHCO3 stress.
Method 2-year-old Rhododendron 'shen zhou qi' cuttage seedlings were subjected to sandy culture in nutrient solution to study the effects of different concentrations of BABA (0, 50, 100, 200, and 400μmol·L-1) on photosynthetic characteristics and antioxidative system of Rhododendron leaves under 50 mmol·L-1 NaHCO3 stress.
Result The biomass of Rhododendron significantly reduced under NaHCO3 stress. Exogenous BABA of 200μmol·L-1 significantly improved the biomass. Exogenous BABA increased chlorophyll a, chlorophyll b and carotenoid content in Rhododendron leaves under NaHCO3 stress, and significantly increased net photosynthetic rate, reduced stomatal conductance and intercellular CO2 concentration. Application of BABA could increase activities of some antioxidant enzymes including superoxide dismutase, peroxidase, catalase, glutathione reductase, ascorbate peroxidase and dehydroascorbate reductase under NaHCO3 stress, resulting in significant lower reactive oxygen species accumulation and membrane lipid peroxidation in alkali-treated Rhododendron leaves.
Conclusion It is suggested that 100-200μmol·L-1 exogenous BABA can effectively alleviate the harm of Rhododendron under NaHCO3 stress.