Speaker
Description
The Mediterranean region is increasingly affected by the consequences of climate change, notably in the form of more frequent and intense drought episodes. In Morocco, erratic rainfall patterns and prolonged dry periods are critically impacting agriculture. Olive trees (Olea europaea), a cornerstone of the region’s agroeconomy and ecological stability, are particularly sensitive to water deficits, which lead to compromised growth, impaired physiological function, and reduced yield quality.
To address this challenge, sustainable agronomic strategies are essential. Biostimulants derived from marine algae have gained attention for their ability to enhance plant resilience by modulating physiological processes, improving water use efficiency, and reinforcing antioxidant defense systems.
This study evaluated the effects of a foliar-applied algae-based biostimulant on young Olea europaea var. Moroccan Picholine plants, cultivated under greenhouse conditions. Plants were subjected to two irrigation regimes: well-watered (WW; 75% field capacity) and drought-stressed (DS; 25% field capacity). The biostimulant was prepared from marine algae collected along the Sidi Bouzid shoreline, processed into an aqueous extract, and applied at two concentrations (3% and 5%) every 20 days over 8 months. Growth metrics, stomatal conductance, and chlorophyll fluorescence (Fv/Fm) were recorded monthly.
Our results demonstrate that biostimulant application significantly enhanced growth and biomass accumulation under both irrigation regimes, indicating improved plant vigor and stress adaptation. Notably, treated plants exhibited increased stomatal conductance, suggesting more efficient regulation of gas exchange and potential improvements in water use efficiency. Furthermore, higher Fv/Fm values in treated plants, particularly under drought stress, indicate enhanced photosystem II efficiency and better maintenance of photochemical activity.
A significant reduction in shoot-to-root ratio was also observed in biostimulant-treated groups, pointing to an adaptive shift in biomass partitioning toward root development—a response commonly associated with improved water and nutrient acquisition under limited moisture availability.
These findings highlight the potential of algae-derived biostimulants as a sustainable and effective tool for mitigating the adverse effects of drought stress in olive cultivation. By promoting physiological resilience and optimizing biomass distribution, such treatments could support the long-term productivity and sustainability of olive groves under changing climatic conditions.
