Carapa Procera Research Articles

Effect of Microhabitat on Seed Fate and Seedling Performance in Two Rodent- Dispersed Tree Species in Rain Forest in French Guiana

1 The establishment probabilities, short-term survival, growth rates and biomass allocation patterns of seedlings in two large-seeded tree species, Carapa procera (Meliaceae) and Vouacapoua americana (Caesalpiniaceae), were studied in contrasting microhabitats at Paracou, French Guiana. 2 Seeds (100 per habitat per species) were buried to simulate rodent caches into gap and understorey microhabitats (n = 20 of each) surrounding mature parent trees. The experiment was replicated in Carapa procera (in early March and May) to investigate the effect of temporal variation in seed dispersal on the establishment process. 3 Surviving seeds and sprouting seedlings were repeatedly censused during 2 years after establishment, and the causes of mortality determined. Growth and biomass parameters were calculated for surviving seedlings after 2.5 years. 4 A greater proportion of seeds and germinating seedlings were dug up but less seedlings suffered from damping-off in C. procera than in V. americana. For both species, short-term survival of seedlings was lower in the understorey where predation by mammals and damping-off occured more frequently than in gaps. 5 Damping off killed more Carapa procera seedlings when buried in March than in May, whereas mammal predation caused more deaths in May planted seeds. 6 Although survival and growth were enhanced in gaps for both species, seeds and seedlings were much more intolerant to the understorey microhabitat in Carapa procera (almost 100% mortality in shaded habitat) than in Vouacapoua americana. 7 Seedling biomass allocation was consistent with previous data for large-seeded species but differed markedly between the two study species.

Genetic diversity and spatial structure within a natural stand of a tropical forest tree species, Carapa procera (Meliaceae), in French Guiana

Isozyme markers were used to characterize levels of diversity, genotypic structure and spatial genetic structure for the low-density tree species, Carapa procera (five adults per ha), within 300 ha of a continuous tropical rain forest stand. Both seed and adult stages were investigated, a high level of genetic diversity being found in both. Fixation indices showed excess homozygosity in seeds, and excess heterozygosity in adults, which might be caused by selection in favour of heterozygotes. Autocorrelation analysis of the spatial distribution of genotypes revealed no significant pattern in adults or in seeds before dispersal, and there was a high variability in correlogram shapes among alleles. This suggests that gene flow is extensive in C. procera, probably mainly through long-distance pollen dispersal, as seed dispersal is expected to be rather limited in this species (maximum distances of about 50 m). No clear-cut spatial pattern was observed in pollen allele frequencies, which supports the hypothesis of extensive pollen flow. This overall lack of structure is consistent with the data already available on the mating system of this predominantly outcrossing species.

Genetic diversity and spatial structure within a natural stand of a tropical forest tree species, Carapa procera (Meliaceae), in French Guiana

Isozyme markers were used to characterize levels of diversity, genotypic structure and spatial genetic structure for the low-density tree species, Carapa procera (five adults per ha), within 300 ha of a continuous tropical rain forest stand. Both seed and adult stages were investigated, a high level of genetic diversity being found in both. Fixation indices showed excess homozygosity in seeds, and excess heterozygosity in adults, which might be caused by selection in favour of heterozygotes. Autocorrelation analysis of the spatial distribution of genotypes revealed no significant pattern in adults or in seeds before dispersal, and there was a high variability in correlogram shapes among alleles. This suggests that gene flow is extensive in C. procera, probably mainly through long-distance pollen dispersal, as seed dispersal is expected to be rather limited in this species (maximum distances of about 50 m). No clear-cut spatial pattern was observed in pollen allele frequencies, which supports the hypothesis of extensive pollen flow. This overall lack of structure is consistent with the data already available on the mating system of this predominantly outcrossing species.

Mating system of Carapa procera (Meliaceae) in the French Guiana tropical forest

The mating system of the tropical rainforest tree Carapa procera was studied for a population located within a sylvicultural trial in French Guiana. We used the mixed-mating model with the genotypes of 47 open-pollinated progenies at ten polymorphic loci, obtained through isozyme analysis. Seeds were collected on both logged and unlogged (control) plots, which were interspersed. A high multilocus outcrossing rate (0.78) was found for the global population. and there was indirect evidence for nonrandom mating for outcrosses. It is argued that this may be due to some kind of positive assortative mating, probably biparental inbreeding. Correlation of selfing between sibs was not significantly different from zero. and the proportion of full-sibs among outcrossed sib-pairs was significant but low (0.16). We found significant differences between outcrossing rates when computing separate estimates for the 14 trees located on logged plots (tm = 0.63) and the 33 trees located on undisturbed plots (tm = 0.85). It is argued that the decrease in density is probably not the only cause of the decrease in outcrossing rate on logged plots. Lastly, several points concerning the reliability of the estimation are outlined. In particular. the downward bias due to ignoring null alleles during genetic interpretations of zymograms is quantified in a few cases by simulating artificial populations.

Removal of seeds ofCarapa procera(Meliaceae) by rodents and their fate in rainforest in French Guiana

ABSTRACTExperiments were performed to investigate monthly variations in seed fate ofCarapa procera(Meliaceae), a rodent-dispersed subcanopy tree species in French Guiana. A total of 600 thread-marked seeds were placed on the ground in mature forest under 20 adult trees during different months (March, April and May 1991) of the species' fruiting season. In 1991 the seed crop reached 1536 seeds in the study area, with a majority of seeds being produced in March and May. On average, seed removal rate steadily increased from March (23%) to May (96%). Of the seeds removed, the proportion eached almost doubled between March (28%)-April (25%) and May (48%), whereas the proportion eaten (gnawed) steadily declined between March (43%) and May (9%). Approximately 75–100% seed removal was therefore associated with intense scatterhoarding and low seed predation, especially in May. Greater seed dispersal rates occurred during the late wet season when fruit diversity decreased but when overall fruit biomass peaked because of fruiting occurrence of large-seeded species. The seasonal hoarding behaviour of rodents is discussed.

Transpiration of natural rain forest and its dependence on climatic factors

Sap flow was measured on several species from the tropical rain forest in French Guiana during two successive years over the dry season. On bright days, sap flow densities (i.e. sap flow per unit of sapwood area) exhibited high variations from one species to another. Higher rates (3 to 4 kg dim −2 h −1) were observed on late stage forest species like Dicorynia guianensis, Eperua falcata or E. grandifolia, and lower rates on Vouacapoua americana and Carapa procera (1.0 to 1.5 kg dm −2 h −1). Calculated stand sap flow ( F) was closely dependant on air vapour pressure deficit and less correlated to global radiation. A simple model of canopy conductance variations and hence of stand transpiration was derived from these measurements. Sap flow was linearly related to Penman Evapotranspiration (PET), the ratio F/PET being close to 0.75 under dry canopy conditions, as previously reported by Shuttleworth et al. (1984) in Central Amazon.

Tannin, phytin and oxalate contents of some wild under-utilized crop-seeds in Nigeria

Eighteen wild under-utilized crop-seeds were investigated for their tannin, phytin and oxalate contents. Tannic acid content ranged between 0·11% in Coula edulis and 1·15% in Lophira alata. Phytic acid content varied between 330 mg/100 g dry matter in Carapa procera and 1580 mg/100 g dry matter in Terminalia catappa. Total oxalate content ranged between 5·34 g/100 g dry matter in Xylopia aethiopica and 14·0 mg/100 g dry matter in Carapa procera. When soluble oxalate was expressed as a percentage of total oxalate, high values were obtained in Vitex doniana (92·21%) and Xylopia aethiopica (82·0%). The antinutritional effects of these components are discussed in relation to (a) their potentials as feed for livestock and (b) their use as spices, condiments and food supplements by the large rural population in Nigeria.

Amino acid composition of seeds of some lesser known tree crops

The amino acid composition of seeds of twenty-six species were determined by column chromatography. Total nitrogen was initially determined by the Kjeldahl procedure. Chemical scores were calculated for the different species using FAO amino acid patterns. Crude protein (N × 6·25) ranged between 8·8% in Afzelia bella (calyx) and 33·2% in Parkia clappertoniana. Afzelia bella (calyx) had the highest values of valine ( 8·9 g 16 gN ); iso-leucine ( 12·5 g 16 gN ); leucine ( 16·8 g 16 gN ) and phenylalanine ( 7·1 g 16 gN ). Parkia clappertoniana, Afzelia bella (seed), Irvingia gabonensis, Monodora tenuifolia, Pterocarpus osun and Cedrella odorata had the highest values of lysine ( 8·0 g 16 gN ); histidine ( 6·3 g 16 gN ); methionine ( 1·9 g 16 gN ); tyrosine, ( 9·1 g 16 gN ); tryptophan ( 2·5 g 16 gN ) and cystine ( 3·6 g 16 gN ), respectively. The proportion of total nitrogen derived from essential amino acids ( E T N ratio) varied from 1·0 in Carapa procera to 4·2 in Afzelia bella (calyx). Chemical score ranged between 22·4 in Afzelia bella (calyx) and 64·7 in Khaya ivorensis.

Composition of Carapa procera Gum

Carapa procera D.C. (family Meliaceae) occurs widely in the forests of the Western Area of Sierra Leone. Between December and February the stem exudes gum varying from pale-green to dark brown. On analysis, a single unpurified nodule gave ash, 1.68 per cent; nitrogen, 0.44 per cent; acetyl groups, 1.84 per cent; alkoxyl groups (calculated as ethoxyl), 2.63 per cent. Results for two other nodules were not significantly different from these. The crude gum dissolves partially in cold water to give a markedly acidic solution.