Physiological responses shown by the apical (green) and basal (brown) leaves of seven taxa of moss family Pottiaceae (Bryophyta): A comparative study from India

Mosses synthesize and preserve a diverse array of secondary metabolites which play a pivotal role in enhancing plant adaptability to environmental fluctuations. These compounds manage reactive oxygen species (ROS) and prevent the uncontrolled oxidation of essential biomolecules. Despite numerous studies highlighting the antibacterial, antifungal, anti-inflammatory, antipyretic, and insecticidal properties of mosses, the antioxidant capacity of mosses remained relatively understudied, with existing research findings dispersed. This investigation aims to evaluate the antioxidant potential and pigment composition of apical green and basal brown leaves of seven species belonging to one of the stress tolerant moss family i.e. Pottiaceae, collected from semi-arid regions of Rajasthan. Remarkable variations in enzymatic responses and chlorophyll concentration were noted among different taxa within the family. The apical green leaves of Hydrogonium consanguineum exhibited the highest superoxide dismutase (SOD) activity, whereas Didymodon vinealis and Hyophila involuta displayed significantly elevated levels of catalase (CAT) and peroxidase (POD), respectively. While previous studies have explored antioxidant activity in various plant parts of angiosperms, such as roots, mature leaves, young leaves, flowers, and fruits, no comparable research has been conducted on moss species within a single family, particularly evaluating apical green and basal brown leaves. Our findings suggest that in contrast to brown leaves, green leaves possess higher antioxidant activity. However, further research is imperative to comprehensively comprehend the antioxidant capacities and active metabolites of the examined moss species.