Reproductive phenology of Scaevola plumieri; a key coloniser of the coastal foredunes of South Africa
2004
Knevel, I.C. | Lubke, R.A.
Given the role of Scaevola plumieri as a major pioneer species in the dune environment, as well as the need forindigenous sand stabilisers for South Africa's coastal dunes, the reproductive phenology was unravelled as a firststep to establish the potential usefulness of the species in dune stabilisation programmes. In the highly variablecoastal environment the plants must cope with many problems for successful reproduction to take place. Theplants of S. plumieri overcome these difficulties through vegetative reproduction, but sexual reproduction is byno means insignificant. Numerous peduncles, each carrying multiple buds, were produced per stem, but only few developed into ripe seeds. Several of the flowers were unfertilised and of the seeds produced many were infected and/or aborted. There was a strong effect of dune position on the reproductive phenology of S. plumieri. The stems situated at the landward face of the foredunes showed an overall higher reproductive performance number of buds, flowers, unripe seeds, ripe seeds. The phenogram showed that the reproduction of stems at the landwardside of the foredunes started on average 34 days earlier and showed a tendency for a longer reproduction period. For the duration of the different stages in the reproduction sequence, the bud stage' took the shortest time and the 'ripe seed stage' longest time. Between the different sample years, the production of the number of peduncles, buds, flowers and seeds was the similar; only differences in reproduction time (duration) of the differentstages were observed for the bud, flower an unripe seeds stage between the sample years.
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