Compost as an eco-friendly alternative to mitigate salt-induced effects on growth, nutritional, physiological and biochemical responses of date palm

Authors

• Mohamed Ait-El-Mokhtar * ^{1, 2}
• Abdessamad Fakhech ²
• Raja Ben-Laouane ²
• Mohamed Anli ²
• Abderrahim Boutasknit ²
• Youssef Ait-Rahou ²
• Said Wahbi ²
• Abdelilah Meddich ²

1. Laboratory of Biochemistry, Environment and Agri-food URAC 36, Department of Biology, Faculty of Science and Techniques – Mohammedia, Hassan II University of Casablanca, Mohammedia, Morocco
2. Laboratory of Agro-Food, Biotechnologies and Valorization of Plant Bioresources (AGROBIOVAL), Department of Biology, Faculty of Science – Semlalia, Cadi Ayyad University, Marrakesh, Morocco

Abstract

Purpose In this study, the role of compost application in alleviating salt stress effects on date palm seedlings growth and development was investigated.
Method The experiment was set in a randomized design, with or without green waste-based compost, and under two salinity levels (0 and 240 mM NaCl). Growth, mineral uptake, photosynthetic pigments content, oxidative stress markers’ accumulation and antioxidant activity were assessed.
Results Plants grown under saline condition showed low values of growth attributes while the application of compost increased these attributes under 240 mM NaCl. Salinity increased sodium (Na⁺) and chlorine (Cl^–) ions concentration in plants and reduced phosphorus (P), nitrogen (N), potassium (K⁺) and calcium (Ca²⁺) uptake. The presence of compost mitigated these effects by improving the concentrations of the essential elements (P, K⁺, N and Ca²⁺) in both plant shoots and roots and by limiting salt ion (Na⁺ and Cl^–) toxicity and thereby induced higher K/Na and Ca/Na ratios. Furthermore, leaf water status, stomatal conductance and photosynthetic efficiency were increased and were coupled with high chlorophyll and protein concentrations in plants amended with compost under salt stress. NaCl stress induced high lipid peroxidation and H₂O₂ accumulation; however, the application of compost lowered these two parameters in stressed plants through stimulation of the antioxidant enzymes activity and increasing soluble sugars and proline accumulation.
Conclusion Results suggest that the green waste-based compost can boost date palm seedlings tolerance in salt-affected soils by mitigating the different adverse effects of salinity stress.

Highlights

• Growth, physiological and biochemical traits of date palm were reduced by salt stress.
• Nutrient uptake and antioxidant system were improved by compost under salt stress.
• The tolerance of date palm to salinity was enhanced by compost application.

Keywords

• Compost
• Antioxidant system
• Date palm
• Mineral uptake
• Salinity
• Salt tolerance