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Keywords: n Gymnocladus assamicusn , Seed priming, Germination behavior, Morpho-physiological responses, Critically endangered Himalayan plant
The critically endangered tree species Gymnocladus assamicus ex P.C. Kanjilal, endemic to the Eastern Himalayas, faces severe challenges to its regeneration and survival due to habitat loss and changing climatic conditions. To explore strategies that enhance its propagation and stress resilience, two independent experiments were conducted. In the first experiment, the effects of different seed priming treatments were evaluated on germination behavior. Seed priming, particularly water soaking combined with heat treatment or GA3 (50 ppm), significantly improved germination and physiological performance under both control and stress conditions. Seed priming significantly improved germination percentage, rate, and uniformity compared to unprimed controls, indicating its effectiveness in overcoming dormancy and promoting early seedling establishment. In the second experiment, unprimed seedlings were exposed to various abiotic stresses, i.e., heat, cold, drought, submergence, and low pH to assess their morphological and physiological responses. Stress treatments markedly reduced growth parameters, membrane stability, and chlorophyll fluorescence efficiency (Fv/Fm), while increasing relative electrolyte leakage. Histochemical staining using Schiff’s reagent, Evans Blue, Nitroblue Tetrazolium (NBT), and 3,3′-Diaminobenzidine (DAB) confirmed oxidative stress and associated cellular damage. Together, these findings highlight the potential of seed priming as an effective pre-sowing strategy to enhance germination and early establishment, while also providing insights into the abiotic stress tolerance mechanisms of G. assamicus. Such integrated understanding contributes to the development of informed conservation and restoration strategies for this endangered Himalayan species.
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Department of Botany, Gauhati University, Guwahati, India