Propagation of Ornamental Plants
19(2): 38-47, 2019
FACTORS AFFECTING SEED PROPAGATION OF HIBISCUS CODDII SUBSP. BARNARDII: A NEW POTENTIAL ORNAMENTAL PLANT
Helena Jacoba du Plessis1*, Riana Kleynhans2, Roumiana Vassileva Nikolova1, and Bronwyn Ann Egan1
1 Department of Biodiversity, University of Limpopo, Private Bag X1106, 0727 Sovenga, South Africa, *Fax: + 27 86 5837133, *E-mail: firstname.lastname@example.org,
2 Department of Horticulture, Tshwane University of Technology, Private Bag X680, 0001 Pretoria, South Africa
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°C, 20°C, 25°C, 30°C, and 35°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°C failed to germinate while 83.3-94% seedling emergence was attained for cultures kept at 20-35°C. However, temperatures above 25°C (30°C and 35°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°C.
Key words: scarification, seed germination, seedling emergence, sulphuric acid