Conservation of genetic diversity in artificially regenerated holm oak (Quercus ilex L.) populations

Reforestation with autochtonous species should take into account the preservation of the variability and the geographical structure of genetic diversity in forest species. In order to provide empirical data, genetic composition of an artificial population of holm oak (Quercus ilex L.) and its natural seed-origin population in Andalusia were analysed with six microsatellite loci. The genetic diversity indices applied show a reduction in the artificial stand if compared with the natural one, probably due to an inappropriate forester seed collection strategy limited to a few trees.

Aspetti genetici di un progetto di rinaturazione con Quercus coccifera L. s.l. nella Riserva Naturale Orientata "Saline di Trapani e Paceco"

Narrow genetic base in forest restoration with holm oak (Quercus ilex L.) in Sicily

International audience; In order to empirically assess the effect of actual seed sampling strategy on genetic diversity of holm oak (Quercus ilex) forestations in Sicily, we have analysed the genetic composition of two seedling lots (nursery stock and plantation) and their known natural seed origin stand by means of six nuclear microsatellite loci. Significant reduction in genetic diversity and significant difference in genetic composition of the seedling lots compared to the seed origin stand were detected. The female and the total effective number of parents were quantified by means of maternity assignment of seedlings and temporal changes in allele frequencies. Extremely low effective ma…

Il ruolo degli interventi di rinaturazione per la conservazione di formazioni forestali isolate: il caso del lecceto di Santocanale in Sicilia.

Convergent Morphological Evolution in Silene Sect. Italicae (Caryophyllaceae) in the Mediterranean Basin

Recent divergence can obscure species boundaries among closely related taxa. Silene section Italicae (Caryophyllaceae) has been taxonomically controversial, with about 30 species described. We investigate species delimitation within this section using 500 specimens sequenced for one nuclear and two plastid markers. Despite the use of a small number of genes, the large number of sequenced samples allowed confident delimitation of 50% of the species. The delimitation of other species (e.g., Silene nemoralis, S. nodulosa and S. andryalifolia) was more challenging. We confirmed that seven of the ten chasmophyte species in the section are not related to each other but are, instead, genetically c…

Effect of number of seed parents on the genetic diversity of artificially regenerated stands of holm oak

Artificial populations of holm oak (Quercus ilex L. s.l.) and their natural seed origin populations selected from Andalusia (Southern Spain) and Sicily (Southern Italy) were analysed with six nuclear microsatellite loci to explore the effect of seed collection methods. Low effective allele numbers (3.07-6.67) and extremely low effective populations sizes (35.4-102.9) were detected in both reforestation stands, probably due to an inappropriate forester seed collection strategy limited to a few mother trees. Analysis of simulated progenies showed that optimal sampling size to obtain seed collections genetically similar to the origin populations should range from 20 to 50 individuals, but coul…

Genetic variability of the endangered island endemic Silene hicesiae Brullo & Signorello (Caryophyllaceae): preliminary results

Casparian Strips in the Leaf Intrastelar Canals of Isoetes duriei Bory, a Mediterranean Terrestrial Species

Abstract Anatomical observations, using light and fluorescence microscopy, were made on leaves of Isoetes duriei to verify the presence of casparian bands around the intrastelar canals. This peculiar anatomical feature, previously reported for some Isoetes species, is confirmed. The possible role of this endodermis-like structure, in the transport of water due to root pressure or in the accumulation of certain metabolites, is discussed in relation to the ecological and anatomical features of the species.