FACTORS AFFECTING SEED PROPAGATION OF HIBISCUS CODDII SUBSP. BARNARDII: A NEW POTENTIAL ORNAMENTAL PLANT

摘要

Hibiscus coddii subsp. barnardii, an endemic South African species, has potential as an ornamental flowering plant. It produces small, hard seeds that are difficult to germinate. The effect of scarification with 25%, 50%, and 98% sulphuric acid (H2SO4) for different durations (5-40 min), and the effect of temperature (15 degrees C, 20 degrees C, 25 degrees C, 30 degrees C, and 35 degrees C) on seed germination on both moist filter paper and vermiculite were studied. Scarification of seeds in 98% H2SO4 for 30 min resulted in the highest final germination on filter paper (88.6%) and vermiculite (80%) cultures which was significantly different from seeds scarified for 5 min (52.9%) and the non-scarified seeds (< 5%). Scarified seeds cultured on filter paper attained 92.7-96% germination for all temperature treatments with no significant difference between the treatments. Seeds in vermiculite cultures incubated at 15 degrees C failed to germinate while 83.3-94% seedling emergence was attained for cultures kept at 20-35 degrees C. However, temperatures above 25 degrees C (30 degrees C and 35 degrees C) had a detrimental effect on seedling survival. The best performance with regard to seed germination and subsequent seedling development (90% survival) was obtained when seeds were scarified with 98% H2SO4 for 30 min and germinated at 25 degrees C.