مشخصات پژوهش

Salvia officinalis L. (sage) is a valuable medicinal plant with various secondary metabolites. These compounds are usually inducible by different stress conditions, for example, water-deficit stress. Therefore, cost-effective and eco-friendly approaches for alleviating water-deficit stress in medicinal plant crops are in high demand. Polyamines (PAs), such as putrescine, have a significant effect on improving crop yield under water-deficit stress conditions. Therefore, a factorial experiment based on a completely randomized design using two factors and three replications was conducted. Treatments included irrigation regime (IR) and timing of IR after foliar application of putrescine (TIRFP) as follows: irrigation after depletion of 20%, 40%, 60%, and 80% available soil water (ASWD). TIRFP was performed at 0, 24, 48, and 72 h. The treatments affected morphological, physiological, molecular, and biochem- ical attributes. TIRFP of 72 h under IR of 80% ASWD improved the leaf area index, relative water content, antioxidant enzyme activities, and total radical scavenging capacity compared with the controlled treatment. The results of real-time quantitative polymerase chain reaction (qRT-PCR) and gas chromatography/mass spectrometry (GC/MS) analysis showed the highest level of sabinene synthase (SS) and bornyl diphosphate synthase (BPPS), the highest contents of 1,8-cineole, β-thujone, and camphor appeared in plants after 72 h of TIRFP under IR of 80% ASWD. The find- ings of this study confirm the protective role of putrescine against water stress. In conclusion, putrescine foliar application allows for balanced water retention. It pre- serves antioxidant capacity resulting in efficient photosynthesis and the restricted risk of oxidative damage under water-deficit stress. It improves sage plants’ physiological attributes and valuable monoterpenes components of essential oil