Salicylic Acid and Superabsorbent Polymers Could Alleviate Water Deficit Stress in Camelina (Camelina Sativa L.)

Agronomic management and application of growth regulators mitigated the negative effects of water deficit and improved seed oil yield and other traits in camelina. This study assessed the effects of salicylic acid (SA) foliar application and soil application of superabsorbent polymer hydrogel (SPH) on the growth and antioxidant production of camelina (Camelina sativa L.) in 50% and 75% field capacity (FC) groups, as well as in a well-watered treatment. Application of SA and SPH significantly increased camelina yield and its components in 75% FC and well-watered treatments. In the control (no SA or SPH), water deficit reduced seed oil by 13% and 35% in 75% FC and 50% FC, respectively. Application of SA and SPH increased seed oil by 5% and 11%, respectively. Photosynthetic rate (A), stomatal conductance (g(s)), and chlorophyll content decreased in the 75% FC and 50% FC treatments. Application of SA and SPH increased in A (26% and 19%) and g(s) (17% and 12%) compared to the control. Superoxide dismutase (SOD), peroxidases (POD), catalases (CAT), and ascorbate peroxidase (APX) activity increased with increased drought stress. The activity of these enzymes increased when SA was applied. Generally, foliar application of SA was more effective than soil application of SPH in camelina to alleviate the injurious effects of drought stress.