Desiccation sensitivity and germination of recalcitrant Garcinia kola heckel seeds

Investigations were undertaking on the desiccation sensitivity as well as on seed germination of recalcitrant Garcinia kola Heckel. Matured fruits were harvested from a moist semi-deciduous forest at Amantia in the Ashanti Region of Ghana. Depulped seeds were mixed with moistened sawdust and placed in white cotton sacks and quickly transported by air to the Seed Conversation Department of the Royal Botanic Gardens in the United Kingdom. Seed equilibrium relative humidity at 20°C and moisture contents on arrival in the U.K were 96.9 and 58.0%, respectively. As whole seeds and proximal parts/sections of the seeds dried in silica gel at 20°C and under shade at room temperature (26-30°C) moisture content, germination and electrical conductivity were measured. Germination percentages of whole seed and proximal parts reduced gradually as they were dried and at moisture contents below 30.0% germination was drastically reduced. The critical moisture content in seeds and seed pieces of G. kola was therefore around 30.0%. Electrical conductivity of leachate from seed increased as seed moisture contents was lowered. When whole seed, proximal sections, half of proximal sections, proximal end cut and distal end cut pieces were incubated, normal seedlings of the species were produced. Conversely, distal and half of distal sections of the seed produced only roots, while middle and half of middle sections of the seeds produced neither roots nor shoots. Germination characteristics of seeds of G. kola demonstrated the existence of polarity. © 2011 Academic Journals Inc.