Plant Biostimulants: Mechanisms and Applications for Enhancing Plant Resilience to Abiotic Stresses

Abiotic stresses are global challenges that cause significant drop in crop yield by interfering with the plant’s metabolism. Biostimulants have emerged as a potentially innovative and ecologically sustainable approach to enhance plant growth and crop productivity under stressful conditions. Through a comprehensive and critical analysis of existing literature, this review provides insight into the mechanisms and effects of biostimulants in promoting plant resilience under stressful conditions. These mechanisms include nutrient uptake enhancement, stress-responsive genes regulation, plant hormone biosynthesis, osmotic adjustment, and antioxidant activity, ultimately leading to improved plant growth and resistance to abiotic stresses. This review deals with major categories of plant biostimulants (seaweeds, microbial biostimulants, humic substances and protein hydrolysates) and explores the mechanisms by which these biostimulants alleviate abiotic stresses. By summarizing the diverse mechanisms and effects of these biostimulants, this review provides valuable insights into their potential application as sustainable strategies for mitigating abiotic stresses.