Lettuce: Biostimulant screening

Objective

To evaluate the efficacy of several biostimulant prototypes in reducing drought stress in young lettuce plants.

Approach

Young lettuce plants were leaf-sprayed with different biostimulant prototypes and, after five days, were subjected to a 10-day water stress period followed by 7 days of rehydration to assess recovery capacity. Throughout the trial, several morphological and spectral parameters were monitored using a 3D imaging phenotyping system and a multispectral camera.

Results

In lettuce, some biostimulant prototypes induced a slower leaf growth rate before the onset of drought stress, followed by an increase in leaf expansion during the stress period itself. Biomass data collected at the final assessment showed that treated plants did not experience a reduction in leaf biomass compared to controls. Instead, certain prototypes stimulated root growth during the pre-stress phase, which supported greater overall plant growth under drought conditions.

Core insight

Selected biostimulant prototypes promoted root system development prior to drought and sustained canopy growth under stress — enhancing lettuce resilience and maintaining productivity under water-limited conditions.