The Simple Molecule Putrescine Enhances Drought Stress Resilience in Camelina sativa L.

Camelina sativa L. is an important plant as a rich source of vegetable oil and omega-3 fatty acids, but drought reduces its growth. In this study, the effect of foliar spraying of putrescine at different concentrations (50, 100, 150, and 200 µmol L⁻¹) on the physiological and biochemical responses of the plant under irrigation regimes (I) (30%, 60%, and 90% depletion of field capacity moisture) was investigated. The results showed that foliar spraying with 150 µmol L⁻¹ putrescine (P150) significantly improved plant growth and yield and photosynthetic efficiency (29%) compared to the control. Also, an increase in proline content (72%), protein (36%), relative water content (25%), soluble sugar (43%), and antioxidant enzyme activity was observed. Seeds of plants sprayed with P150 had higher phosphorus uptake (35%) and their oil yield increased by 49%. Seed fatty acid composition was also improved, with levels of linolenic acid and linoleic acid increasing by 25 and 32%, respectively. The novelty of this study shows that spraying P150 in the presence of moderate drought stress (60% drainage) is the most optimal treatment in Camelina sativa. Graphical abstract