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Habitat degradation can reduce or even prevent the reproduction of previously abundant plant species. To develop appropriate management strategies, we need to understand the reasons for reduced recruitment in degraded ecosystems. The dioecious coco de mer palm (Lodoicea maldivica) produces by far the largest seeds of any plant. It is a keystone species in an ancient palm forest that occurs only on two small islands in the Seychelles, yet contemporary rates of seed production are low, especially in fragmented populations. We developed a method to infer the recent reproductive history of female trees from morphological evidence present on their inflorescences. We then applied this method to investigate the effects of habitat disturbance and soil nutrient conditions on flower and fruit production. The 57 female trees in our sample showed a 19.5‐fold variation in flower production among individuals over a seven‐year period. Only 77.2% of trees bore developing fruits (or had recently shed fruits), with the number per tree ranging from zero to 43. Flower production was positively correlated with concentrations of available soil nitrogen and potassium and did not differ significantly between closed and degraded habitat. Fruiting success was positively correlated with pollen availability, as measured by numbers and distance of neighboring male trees. Fruit set was lower in degraded habitat than in closed forest, while the proportion of abnormal fruits that failed to develop was higher in degraded habitat. Seed size recorded for a large sample of seeds collected by forest wardens varied widely, with fresh weights ranging from 1 to 18 kg. Synthesis: Shortages of both nutrients and pollen appear to limit seed production of Lodoicea in its natural habitat, with these factors affecting different stages of the reproductive process. Flower production varies widely amongst trees, while seed production is especially low in degraded habitat. The size of seeds is also very variable. We discuss the implications of these findings for managing this ecologically and economically important species.  相似文献   
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The ‘Vallée de Mai’ on the island of Praslin in the Seychelles group is a World Heritage Site because of its unique forest vegetation dominated by the palm Lodoicea maldivica. However, despite its great conservation importance, the stand structure, species diversity and regeneration of this forest have not previously been studied. Moreover, the conservation value of the reserve is currently threatened by invading alien plants and limited regeneration of some native species. The species composition of the forest was studied in six permanent plots (1985 and 1998) and along seven trail transects (1997). To explain potential variation in tree regeneration, the light climate within all plots was investigated using hemispherical photographs. The results reveal little change in forest structure, species diversity and regeneration in the permanent plots over the 13‐year period, but some regeneration of most woody species, presence of some alien species and a relatively high species turnover. We found no significant influence of local light climate upon forest structure, species diversity or regeneration. Although the stand characteristics seem to be relatively stable, the permanent plots and transects should be monitored in order to detect future changes in stand structure and to optimize the protection of this unique forest reserve.  相似文献   
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In the present study, we report the attempt to characterize the chemical composition of fruit kernel of Lodoicea maldivica coco nucifera palm (commonly named as ‘Coco de mer’) by gas chromatographic method. The analysis was performed by HS‐SPME and GC/MS techniques to determine volatile aroma, sterol, and fatty acid composition profiles in the internal and external pulp of two distinct coconuts. Although no qualitative differences in flavour composition were observed between the two analysed coconuts and the relative two pulp parts, variations in the abundance levels of the prominent compounds have been recorded. The averaged quantity of total phytosterols, resulting from the two analysed ‘Coco de mer’ samples, was almost constant in both kernels coconut, being 24.5 μg/g (of dry net matter) for the external, and 26.9 μg/g (of dry net matter) for the internal portion. In both coconuts, the fatty acid pattern composition was characterized by seven saturated acids ranged from C14:0 (myristic) to C20:0 (arachidic) and two monounsaturated acids, the palmitoleic (C16:1, ω7) and the oleic (C18:1, ω9). Palmitic acid (C16:0) was the predominant one with an average contribution of about 49.0%, followed by pentadecanoic 16.5%, stearic (C18:0) 11.6%, and myristic (C14:0) 9.9% acids in all two examined kernel portions.  相似文献   
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