Hermetic effect of Moringa oleifera leaf extract mitigates salinity stress in maize by modulating photosynthetic efficiency, and antioxidant activities

Abstract

Salinity poses a significant constraint to cereal productivity particularly in arid and semiarid regions. The application of allelochemical has shown promising results in mitigating the intensity of abiotic stresses. A pot experiment was conducted to assess the efficacy of different concentrations of aqueous allelopathic extract derived from moringa leaves in mitigating the adverse impacts of salinity on the germination and growth of maize cultivars via seed priming. The study involved three variables: two cultivars of maize, ‘Pioneer 30Y87’ (salt tolerant) and ‘Pioneer 30T60’ (salt sensitive) e seed priming with moringa leaf extract (MLE) at varying concentrations of 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, and hydro-priming as control; and different salinity levels of 0, 6, and 12 dS m-1. Salinity had a negative impact on the germination process, leading to delayed and suboptimal growth of seedlings. Additionally, salinity reduced the synthesis of photosynthetic pigments (20-50%), photosynthesis, transpiration, internal carbon, and stomatal conductance. Further, MLE also improved the antioxidant activities (catalase: CAT and peroxidase: POD) by 22-56% which reduced the hydrogen peroxide production. Moreover, ‘P-30Y87’ exhibited favorable performance in terms of better germination, growth, photosynthesis and antioxidant activities. The application of moringa leaf extract (3%) resulted in a more notable hermetic effect in elevating salinity stress thereby enhancing germination, growth, photosynthesis and antioxidant activities. In the conclusion, application of MLE (3%) is a promising approach to mitigate the adverse impacts of salinity by improving germination, growth, photosynthesis and antioxidant activities.

Keywords

• abiotic stress
• allelopathic hormesis
• Moringa oleifera
• priming
• salinity