Impact of emerging bio-stimulants on the morpho-physiological performance of underutilized fruit crops

Abstract

Emerging bio-stimulants including natural plant extracts, beneficial microbes and novel organic compounds are gaining attention as sustainable tools to enhance crop growth and stress resilience. This review examines how such bio-stimulants influence the morphological and physiological development of underutilized fruit crops worldwide. Underutilized fruits (e.g. baobab, dragonfruit, Indian gooseberry and many indigenous species) are valued for their nutrient density and climate resilience but often suffer from low yields and limited research. Bio-stimulants derived from seaweed, humic substances, protein hydrolysates, chitosan, silicon and microbial inoculants can significantly improve plant height, root development, leaf area, flowering, fruit set and overall yield in diverse fruit species. They also enhance physiological functions such as photosynthesis, nutrient uptake, hormone balance and antioxidant activity, helping plants cope with stresses like drought, salinity, or pests. Global studies indicate consistent benefits: for example, seaweed extract sprays boost fruit size and vitamin content in apples and peaches, while microbial inoculants (e.g. Rhizobium, Bacillus) fix nitrogen or mobilize phosphorus to benefit legumes and fruit trees. By integrating examples from major and minor fruit crops, this article highlights how bio-stimulants can unlock the potential of neglected fruit species. The review covers the historical context of bio-stimulant use, key categories of stimulants, specific effects on growth and physiology, practical applications and worldwide perspectives. It concludes that expanding bio-stimulant research and application in underutilized fruit cultivation could promote sustainable production, nutritional security and climate adaptation on a global scale.