Search

We have examined the phylogeny of the Cyatheaceae s.l. by integrating data obtained from a wide selection of living tree fern species with evidence from the fossil record. Chloroplast DNA restriction site variation and nuclear ribosomal ITS sequence data from extant tree ferns from both the neotropical and paleotropical regions have defined the main evolutionary lineages among the scaly tree ferns. Relationships among a smaller sample of species from the Cyatheaceae s.s., the Dicksoniaceae, and other related families have been examined using sequences from the chloroplast gene, rbcL. Combining the molecular information with a broad array of morphological characters from the leaves, stems and spores has reinforced our concepts of the main evolutionary lineages and revealed unique origins for some characters and multiple origins for others. A new suite of characters from detailed analyses of stem anatomy and petiole vasculature of both living and fossil tree ferns has been added. A global cladistic analysis of all the data provides new insights into the evolution of the group and represents the first attempt to integrate molecular, morphological, and anatomical data from living and fossil taxa for a large family of ferns.

Whether sex chromosomes are differentiated is an important aspect of our knowledge of dioecious plants, such as date palm ( Phoenix dactylifera). In this crop plant, the female individuals produce dates, and are thus the more valuable sex. However, there is no way to identify the sex of date palm plants before reproductive age, and the sex-determining mechanism is still unclear., To identify sex-linked microsatellite markers, we surveyed a set of 52 male and 55 female genotypes representing the geographical diversity of the species., We found three genetically linked loci that are heterozygous only in males. Male-specific alleles allowed us to identify the gender in 100% of individuals. These results confirm the existence of an XY chromosomal system with a nonrecombining XY-like region in the date palm genome. The distribution of Y haplotypes in western and eastern haplogroups allowed us to trace two male ancestral paternal lineages that account for all known Y diversity in date palm., The very low diversity associated with Y haplotypes is consistent with clonal paternal transmission of a nonrecombining male-determining region. Our results establish the date palm as a biological model with one of the most ancient sex chromosomes in flowering plants. [ABSTRACT FROM AUTHOR]

The article offers information on palm landscaping in the Andean cities. Though the Andean cities grow few extensive species used around the world, the landscaping is enriched with native species. The commonly grown species are from the genera parajubaea and ceroxylon that are difficult to grow to maturity and are rarely seen outside their native region. Several palm species are grown in Ecuador including ceroxylon ventricosum, ceroxylon echinulatum and jubaea chilensis.

This article examines the impact of forest disturbance on the palm trees of New Caledonia, where alteration of natural habitats has been extensive. Due to mining activities, logging and land conversion for agriculture, Primary forests have been greatly reduced and highly fragmented all over the island. The tropical rainforest of New Caledonia is a very dynamic and changing ecosystem even under natural conditions, which can cause damage to the forest. Some species are specialized to surviving such damage through mast seeding.

Provides information on Rhopalostylis baueri on Norfolk Island. Background on the geography of the island; Description of the palm variety; Impact of the invasive strawberry guava tree on protected forests on the island.

Presents an article on observing palms along the Rio Napo, a tributary of the Amazon River, during an expedition. Background on palm varieties abundant in Ecuador; Description of the Peruvian course of the Rio Napo; Distribution patterns of different palms species along the tributary.

Fourteen microsatellite loci ofPhoenix dactyliferawere targeted to examine the genetic diversity in Tunisian date-palms germplasm. They showed a high level of polymorphism in 49 accessions from three main oases with little geographic structure within Tunisia. The microsatellite data agrees with previous analyses of Tunisian germplasm using other molecular markers. 100% of local date-palms accessions were successfully fingerprinted and easily distinguished by the help of only three loci. The possibility of using microsatellites for large scale molecular labelling of offshoots and in vitro plantlets and their implication in the plant material certification is discussed. [ABSTRACT FROM AUTHOR]

Describes an unusual transformation of inflorescences in Socratea salazarii. Example of how vegetative transformation of inflorescences occur in Monocotyledons; Species that produce vegetative shoots at the tip of fertile inflorescences; Information on how vegetative development of inflorescence tissues can be induced.

Wax palms are an important element of the cloud forests in the tropical Andes. Despite heavy deforestation, the density of adults seems to be similar in deforested pastures as in forests. We aimed to infer the mechanisms responsible for this apparent resilience in pastures and we tested two hypotheses to explain it: 1) adult palms survived in pastures because they were spared from logging, and 2) adults occurred in pastures through the resilience of large juvenile rosettes, which survived through subterranean meristems and later developed into adults. For this purpose, we characterized the demographic structure of C. quindiuense in a total of 122 plots of 400 m2 in forests and pastures at two sites with contrasted land use histories in Colombia and Peru. Additionally, we implemented growth models that allowed us to estimate the age of individuals at four sites. These data were combined with information collected from local land managers in order to complete our knowledge on the land use history at each site. At two sites, the presence of old individuals up to 169 years and a wide age range evidenced that, at least, a portion of current adults in pastures were spared from logging at the time of deforestation. However, at the two other sites, the absence of older adults in pastures and the narrow age range of the populations indicated that individuals came exclusively from rosette resilience. These interpretations were consistent with the land use history of sites. In consequence, the combination of the two hypotheses (spared individuals and rosette resilience) explained patterns of C. quindiuense in pastures on a regional scale. Regeneration through subterranean meristems in palms is an important, yet overlooked mechanism of resilience, which occurs in a number of palm species and deserves being integrated in the conceptual framework of disturbance ecology. [ABSTRACT FROM AUTHOR]

Ongoing phylogenetic studies are revealing surprising relationships among species, greatly challenging the classical interpretation of characters in Attalea, and forcing us to rethink completely the morphology of these palms. [ABSTRACT FROM AUTHOR]

Phoenix sylvestris has often been regarded as the wild progenitor of the cultivateddate palm Phoenix dactylifera. A genetic study recently discarded this hypothesis, suggesting however a possible occurrence of hybridization events during theexpansion of date palm cultivation. A sampling campaign was carried out in Northwestern India as a first step towards understanding the complex relationships between these two species. [ABSTRACT FROM AUTHOR]