Abstract
M.Sc. (Botany)
Seed dormancy in Cyclopia spp. (Fabaceae) was investigated using seed from the seeder C. subternata and the resprouter C. intermedia obtained from the Southern Cape region. Seed of both species exhibited seed coat imposed dormancy which could be broken by scarification of the seed coat. However, in addition to an impermeable seed coat, seeds from C. intermedia also exhibit an embryo imposed dormancy which could be
broken by cold treatment. Treatment of the seeds with gibberellic acid (GA3 ) , cytokinin (BA) and ethylene could be substituted for the cold treatment. The ethylene sensitivity of the seeds could be enhanced with short-chain saturated fatty acids (octanoic acid)
which further stimulated germination. The effect of plant-derived smoke was also investigated and it appears that, in combination, ethylene and short-chain saturated fatty acids present in the smoke stimulate germination of the seeds. Treatment of the seeds
with norbornadiene (NBD) before the above treatments resulted in the inhibition of germination, indicating that germination of the seeds of Cyclopia spp. is primarily controlled by the action of ethylene. The interaction between cold treatment, GA3 , BA and ethylene during germination of the seeds will be discussed.