Mechanisms of branched chain amino acids promoting growth and lipid accumulation in Camelina sativa seedlings under drought and salt stress

Drought and salt stress are important limiting factors affecting the growth of crop seedlings. In this study, the oil crop C. sativa was selected as the experimental material. This study investigated the effects of BCAAs (branched chain amino acids, including Leu, Ile, and Val) on plant growth, lipid content, antioxidant enzymes, intracellular substances, and photosynthetic activity of C. sativa. BCAAs at 100 µM concentration, were foliar sprayed separately, along with an equal amount of water, under normal, PEG (0.20 g mL⁻¹), and NaCl (150 mM) conditions. The results illustrated that both PEG and NaCl markedly reduced the total lipid and soluble protein contents, inhibiting the growth of C. sativa seedlings significantly, including a decrease in height, biomass, and chlorophylls. BCAAs supplementation effectively mitigated the detrimental effects of drought and salt. Foliar spraying BCAAs mainly worked by increasing soluble sugars and proteins, enhancing enzymatic activities of antioxidant enzymes, improving photosynthesis parameters (Fv/Fm and Y(II)), thereby promoted lipid accumulation and seedlings growth of C. sativa, with Val showing the best performance. The current study would provide the theoretical basis and technical support for enhancing lipid production and promoting seedling growth of C. sativa to abiotic stress by applying exogenous BCAAs.