Biostimulant derived from Spirulina platensis improves emergence and quality of melon seedlings

Abstract

This study hypothesized that seed treatment with Spirulina platensis enhances melon seedling emergence and quality. The objective was to evaluate the effect of an S. platensis-based biostimulant applied via seed treatment on melon seedling development. The experiment followed a completely randomized design in a 2 × 3 + 2 factorial arrangement, with four replicates of 25 seedlings per treatment. The treatments consisted of two types of S. platensis-based biostimulants (filtrate and residue), each applied at three concentrations (5, 15, and 25%). Additionally, two controls were included: seeds immersed in distilled water and seeds sown under dry conditions (without immersion). Twenty-five days after emergence, the filtrate treatments positively influenced stem diameter, root fresh mass, and leaf greenness index (colorimetry), with the 25% concentration notably enhancing root system development. The biostimulant filtrate at a concentration of 25% resulted in a higher number of leaves and higher Dickson quality index values. The largest seedlings were obtained with the biostimulant residue at a concentration of 5%. Interestingly, the dry condition (no seed immersion) yielded the highest average values for both emergence percentage and emergence speed index. Conversely, immersion in water alone negatively affects these parameters. Biostimulant filtrate at concentrations ranging from 5 to 25% promotes superior emergence speed and overall seedling vigor, effectively optimizing biomass distribution. It thus represents an efficient and sustainable biotechnological tool for improving crop establishment.