Enhancing Irrigation Salinity Stress Tolerance and Increasing Yield in Tomato Using a Precision Engineered Protein Hydrolysate and Ascophyllum nodosum-Derived Biostimulant

Most vegetable crops are salt sensitive, growing inadequately in salinised soils due to the accumulation of toxic ions from prolonged irrigation regimes. Plant biostimulants are a potential tool that can be used to counteract salinity stress and increase crop yield. The aim of this study was to investigate the ability of the proprietary protein hydrolysate and Ascophyllum nodosum-derived biostimulant PSI-475 to activate salinity stress tolerance responses in plants. After characterising PSI-475 composition, initial biostimulant activity screening was performed using Arabidopsis thaliana. PSI-475 stimulated primary root growth (+5.5-20.0%) and photosynthetic pigments content (18.8-63.0%) under unstressed and salinity stressed conditions. Subsequently, PSI-475 was assessed by foliar application on tomato plants (cv. Micro-Tom) that received a saline irrigation water program, which caused a significant decrease in fruit yield (-37.5%). Stressed plants treated with PSI-475 increased this parameter by 31.8% versus the stressed control. Experimental data suggest that PSI-475 can alleviate the negative effects of saline irrigation by improving osmotic adjustment and ion homeostasis markers. PSI-475 was also able to provide significant yield benefits in unstressed plants (+16.9%) that were associated with improved leaf biochemical markers. The data presented support the use of this precision biostimulant to target the negative effects of salinity stress from irrigation.

Automated summary

This study investigated the effectiveness of a proprietary protein hydrolysate and Ascophyllum nodosum-derived biostimulant PSI-475 in improving plant tolerance to salinity stress. Results showed that PSI-475 stimulated root growth and photosynthetic pigments content in both unstressed and salinity stressed conditions. Foliar application of PSI-475 on tomato plants also increased fruit yield and improved osmotic adjustment and ion homeostasis markers. The use of PSI-475 as a precision biostimulant to mitigate the negative effects of salinity stress from irrigation is supported by the experimental data.