Experimental studies on seed germination of Nothopegia castaneifolia an endemic & critically endangered tree of the Western Ghats, India

Abstract Nothopegia castaneifolia (Roth) Ding Hou (Anacardiaceae) is a critically endangered tree species with a narrow endemic range, restricted to semi-evergreen and evergreen forests of the Western Ghats, one of India’s biodiversity hotspots. Owing to the highly recalcitrant nature of its seeds and the decline of natural populations, x ex-situ conservation strategies are essential for population restoration. The effectiveness of pre-sowing treatments, including H2SO4 scarification, GA3 at 500 and 1000 ppm, and hot water, was evaluated for enhancing seed germination. Germination varied significantly among treatments, with H2SO4 scarification (3 min, 80.0 ± 2.3%) and GA3 application (500–1000 ppm; 75.0 ± 2.0% and 72.0 ± 2.1%) being the most effective, as confirmed by ANOVA and Tukey’s HSD analyses. These findings demonstrate that H2SO4 scarification and GA3 treatments effectively break dormancy and enhance germination, supporting ex-situ conservation of Nothopegia castaneifolia.