Genetic structure, mating system, and long-distance gene flow in heart of palm (Euterpe edulis Mart.). (9/237)

We report a detailed analysis of the population genetic structure, mating system, and gene flow of heart of palm (Euterpe edulis Mart.-Arecaceae) in central Brazil. This palm is considered a keystone species because it supplies fruits for birds and rodents all year and is intensively harvested for culinary purposes. Two populations of this palm tree were examined, using 18 microsatellite loci. The species displays a predominantly outcrossed mating system (tm = 0.94), with a probability of full sibship greater than 70% within open-pollinated families. The following estimates of interpopulation genetic variation were calculated and found significant: FIT = 0.17, FIS = 0.12, FST = 0.06, and RST = 0.07. This low but significant level of interpopulation genetic variation indicates high levels of gene flow. Two adult trees were identified as likely seed parents (P > 99.9%) of juveniles located at a distance of 22 km. Gene flow over such distances has not been reported before for tropical tree species. The establishment and management of in situ genetic reserves or ex situ conservation and breeding populations for E. edulis should contemplate the collection of several hundreds open-pollinated maternal families from relatively few distant populations to maximize the genetic sampling of a larger number of pollen parents.  (+info)

Structural features of N-glycans linked to glycoproteins from oil palm pollen, an allergenic pollen*. (10/237)

The pollen of oil palm (Elaeis guineensis Jacq.) is a strong allergen and causes severe pollinosis in Malaysia and Singapore. In the previous study (Biosci. Biotechnol. Biochem., 64, 820-827 (2002)), from the oil palm pollens, we purified an antigenic glycoprotein (Ela g Bd 31 K), which is recognized by IgE from palm pollinosis patients. In this report, we describe the structural analysis of sugar chains linked to palm pollen glycoproteins to confirm the ubiquitous occurrence of antigenic N-glycans in the allergenic pollen. N-Glycans liberated from the pollen glycoprotein mixture by hydrazinolysis were labeled with 2-aminopyridine followed by purification with a combination of size-fractionation HPLC and reversed-phase HPLC. The structures of the PA-sugar chains were analyzed by a combination of two-dimensional sugar chain mapping, electrospray ionization mass spectrometry (ESI-MS), and tandem MS analysis, as well as exoglycosidase digestions. The antigenic N-glycan bearing alpha1-3 fucose and/or beta1-2 xylose residues accounts for 36.9% of total N-glycans: GlcNAc2Man3Xyl1Fuc1GlcNAc2 (24.6%), GlcNAc2Man3Xyl1GlcNAc2 (4.4%), Man3Xyl1Fuc1-GlcNAc2 (1.1%), GlcNAc1Man3Xyl1Fuc1GlcNAc2 (5.6%), and GlcNAc1Man3Xyl1GlcNAc2 (1.2%). The remaining 63.1% of the total N-glycans belong to the high-mannose type structure: Man9GlcNAc2 (5.8%), Man8GlcNAc2 (32.1%), Man7GlcNAc2 (19.9%), Man6GlcNAc2 (5.3%).  (+info)

Raphides in palm embryos and their systematic distribution. (11/237)

BACKGROUND AND AIMS: Raphides are ubiquitous in the palms (Arecaceae), where they are found in roots, stems, leaves, flowers and fruits. Their occasional presence in embryos, first noticed over 100 years ago, has gone largely unexamined. METHODS: Embryos from 148 taxa of palms, the largest survey of palm embryos to date, were examined using light microscopy of squashed preparations under non-polarized and crossed polarized light. RESULTS: Raphides were found in embryos of species from the three subfamilies Coryphoideae, Ceroxyloideae and Arecoideae. Raphides were not observed in the embryos of species of Calamoideae or Phytelephantoideae. The remaining subfamily, the monospecific Nypoideae, was not available for study. CONCLUSIONS: Within the Coryphoideae and Ceroxyloideae, embryos with raphides were rare, but within the Arecoideae, they were a common feature of the tribes Areceae and Caryoteae.  (+info)

Investigation of genetic and morphological variation in the sago palm (Metroxylon sagu; Arecaceae) in Papua New Guinea. (12/237)

BACKGROUND AND AIMS: The genetic and morphological variation in the sago palm (Metroxylon sagu, Arecaceae) in Papua New Guinea (PNG) was investigated. METHODS: Amplified fragment length polymorphism (AFLP) was used to investigate the genetic structure of 76 accessions of M. sagu, collected in seven wild and semi-wild stands in PNG. KEY RESULTS: An analysis of ten quantitative morphological variables revealed that most of these were mutually correlated. Principal component analyses of the same morphological variables showed that neither armature (presence or absence of spines) nor geographical separation was reflected clearly in the quantitative morphological variation. Similarity matrices of genetic, quantitative morphological, geographical and armature data were tested for pair-wise correlations, using Mantel's test. The results only showed a significant correlation between genetic and geographical distances. Visual inspection of principal component analyses plots and a neighbour-joining dendrogram based on genetic distances supported this trend, whereas armature showed no relation with genetic distances. CONCLUSIONS: Geographical distribution defines some weak patterns in the genetic variation, whereas the genetic variation does not reflect any patterns in the morphological variation, including armature. The present study supports the accepted taxonomy of M. sagu, recognizing only one species of M. sagu in PNG.  (+info)

Allozyme variation and structure of the Canarian endemic palm tree Phoenix canariensis (Arecaceae): implications for conservation. (13/237)

Electrophoretic analysis of 18 allozyme loci was used to estimate the levels and structuring of genetic variation within and among natural populations of the protected endemic palm species from the Canary Islands (Phoenix canariensis) to evaluate its genetic relationship with the widespread congener P. dactylifera, and to assess comparatively the genetic variation in the populations where the two species coexist with morphologically intermediate plants (mixed populations). Our survey revealed that the within-population component explains roughly 75% of the genetic variation levels detected in P. canariensis (A=1.59; P=41.8; He=0.158), which rank higher than those reported for other species of the Arecaceae. A Principal Component analysis (PCA) based on allele frequencies consistently separates populations of P. canariensis and P. dactylifera, and reveals a close genetic relationship between P. canariensis and the mixed populations. Reduced levels of genetic variation in P. canariensis with respect to P. dactylifera, the fact that the genetic makeup of the Canarian endemic (with no unique alleles) is a subset of that found in P. dactylifera, and the high genetic identity between both species strongly suggest that P. canariensis is recently derived from a common ancestor closely related to P. dactylifera.  (+info)

Falling palm fronds structure amazonian rainforest sapling communities. (14/237)

The senescence and loss of photosynthetic and support structures is a nearly universal aspect of tree life history, and can be a major source of disturbance in forest understoreys, but the ability of falling canopy debris in determining the stature and composition of understorey communities seems not to have been documented. In this study, we show that senescent fronds of the palm Iriartea deltoidea cause substantial disturbance in tropical forest sapling communities. This disturbance influences the species composition of the canopy and subcanopy by acting as an ecological filter, favouring sapling species with characteristics conducive to recovery after physical damage. The scale of this dominance suggests that falling I. deltoidea debris may be influencing sapling community structure and species composition in Amazonian rainforests over very large spatial scales.  (+info)

Genetic consequences of tropical second-growth forest regeneration. (15/237)

Secondary forests are more extensive than old-growth forests in many tropical regions, yet the genetic composition of colonizing populations is poorly understood. We analyzed the parentage of a founder population of 130 individuals of the canopy palm Iriartea deltoidea in a 24-year-old second-growth forest in lowland Costa Rica. Among 66 trees in adjacent old-growth forest, only two individuals contributed 56% of the genes in founders. Second-growth trees had lower genetic diversity and larger patches of similar genotypes than old-growth trees. Recovery of genetic diversity of populations in tropical second-growth forests may take many generations and will require continued dispersal from genetically diverse source populations.  (+info)

Paenibacillus phyllosphaerae sp. nov., a xylanolytic bacterium isolated from the phyllosphere of Phoenix dactylifera. (16/237)

A bacterial strain, designated PALXIL04(T), was isolated from the phyllosphere of Phoenix dactylifera. Phylogenetic analysis placed the isolate within the genus Paenibacillus with the closest relatives being Paenibacillus curdlanolyticus and Paenibacillus kobensis. DNA-DNA hybridization measurements showed low DNA relatedness (15-20 %) between the isolate and its closest relatives. Cells were Gram-variable, facultatively anaerobic, motile, sporulating rods. Catalase and oxidase were produced by the organism. Cellulose, starch, aesculin and xylan were hydrolysed. Growth was supported by many carbohydrates as the carbon source. MK-7 was the predominant menaquinone and anteiso-C(15 : 0) the major fatty acid. The G+C content of the DNA was 50.7 mol%. Phylogenetic, DNA-DNA relatedness and phenotypic analyses indicated that strain PALXIL04(T) represents a novel species of the genus Paenibacillus, for which the name Paenibacillus phyllosphaerae sp. nov. is proposed. The type strain is PALXIL04(T) (=LMG 22192(T)=CECT 5862(T)).  (+info)