Regulatory Role of Plant-Based Biostimulants in Chlorophyll Biosynthesis and Endogenous Hormone Regulation in Plants

Plant-based bio-stimulants offer a sustainable approach to enhancing plant growth by influencing physiological processes such as chlorophyll biosynthesis and hormone regulation. This study investigates the effects of aqueous leaf extracts from Justicia gendarussa , Osmunda regalis , and Senna occidentalis on chlorophyll content and endogenous hormone levels in rice ( Oryza sativa ) plants. Seeds were treated with varying extract concentrations (10%, 20%, and 50%) and analyzed after four weeks. Results showed a significant, dose-dependent increase in chlorophyll a and b content, with J. gendarussa at 100% concentration yielding the highest chlorophyll a (7.21 mg/g) and chlorophyll b (3.23 mg/g) levels. Endogenous hormone levels were also elevated, with J. gendarussa treatment resulting in auxin (12.53 µg/g), gibberellin (9.63 µg/g), and cytokinin (6.57 µg/g) concentrations. ANOVA confirmed the statistical significance of both plant type and extract concentration on chlorophyll and hormone levels ( p  < 0.05). These findings highlight the potential of these natural extracts, particularly J. gendarussa , as eco-friendly bio-stimulants for improving rice plant physiology and promoting sustainable agriculture.