Responses to Seed Dormancy Breaking Treatments in Wild Hibiscus species

摘要

To determine the most suitable means of overcoming seed dormancy in seven wild species of Hibiscus (Hibiscus acetosella Welw. ex Fie, Hibiscus calyphyllus Cav., Hibiscus surattensis L, Hibiscus lobata Kuntze, Hibiscus radiatus Cav, Hibiscus vitifoliusL, Hibiscus panduriformis Burm. f) and their accessions, seeds were exposed to various pre-treatments such as scarification with hot water and sulphuric acid for varying durations. Treated seeds were evaluated for their viability to assess the impact ofgiven treatments. The results revealed that concentrated sulphuric acid scarification treatment for 10 min was highly effective in breaking hard-seed dormancy in all accessions of H. calyphyllus .Concentrated sulphuric acid treatment for 10-20 min in H.vitifolius, 25 min in H. surattensis; 30 min in H. radiatus; 5min in H. lobatus was effective in overcoming hardseededness. Hot water treatment at 80°C for 10 min was effective in H. acetosella and H. panduriformis. However in H. panduriformis concentrated acid treatment for 5min was equally effective as hot water treatment. This study therefore clearly demonstrates the efficacy of concentrated sulphuric acid pre-treatment for 10-30 min and hot water treatment at 80°C for 10 min as an effective enhancer of seed germination of wild species of Hibiscus. Because of the variation in the seed size and degree of hardseededness among the species no single treatment can be recommended for breaking dormancy in all species.