Calcium nitrate delays climacteric of persimmon fruit

Calcium nitrate (20 g litre^?1) delayed persimmon (Diospyros kaki) ripening on the tree and also reduced postharvest fruit deterioration when applied prior to fruit colour break. The magnitude of the response depended on the date of treatment. Application made one month prior to the peak of estimated commercial harvest was the most efficacious, and colour development, fruit softening and ethylene production were significantly retarded by the treatment. At harvest, there was no effect on fruit size or soluble solids content. Although there was a tendency for the content of soluble solids and fruit firmness to decrease with storage period, firmness of treated fruit was maintained.     

Taxonomy,skull diversity and evolution in a species complex of Myotis (Chiroptera: Vespertilionidae): a geometric morphometric appraisal

Phylogenetic relationships between taxa are not necessarily reflected by morphological data due to widespread homoplasy and convergence. However, combining morphological and molecular data provides insights into the evolution of biological forms and into the potential factors involved. Here we focus on a complex of three taxa of bats with unclear taxonomic affinities: Myotis myotis, Myotis blythii and Myotis punicus. Traditional morphometric methods failed to separate them, whereas recent molecular‐based studies suggested that they constitute separate biological species. In the present study, landmark‐based geometric morphometrics methods have been used to analyse the skull variability of 218 specimens belonging to this species complex. Patterns of size and shape delimitate three morphological groups that are congruent with the proposed taxonomic assignments, and therefore support species rank for all three major groups. These morphometrics results, however, suggest that M. myotis and M. punicus share shape characteristics in the rostrum and in the posterior part of the skull that differ from M. blythii. Because previous molecular phylogenetic analyses suggested that M. myotis and M. blythii are sister species, we interpret the similitude in skull morphology between M. myotis and M. punicus as a convergence probably related to their similar feeding habits. Within the taxon M. punicus, the skull of Corsican and Sardinian populations significantly differs from that of Maghrebian ones, suggesting the existence of further cryptic taxonomic diversity. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 529–538.     

Wild and agronomically important Agave species (Asparagaceae) show proportional increases in chromosome number,genome size,and genetic markers with increasing ploidy

Agave (Asparagaceae) includes cultivated and wild varieties of henequen used for hard fibre production. As part of a breeding programme to improve Agave production, species with different ploidy levels were genetically characterized: two diploids [A. tequiliana Weber and the hybrid H11648 ((A. amaniensis Trel. & Nowell × A. angustifolia Haw.) × A. amaniensis)], a triploid (A fourcroydes Lem. var. kitam ki), a tetraploid (A. angustifolia var. letona), three pentaploids (A. fourcroydes var. sac ki, A. fourcroydes var. yaax ki, and A. sisalana Perrine), and two hexaploids (A. angustifolia var. chelem ki from two locations). Chromosome spreading was used to determine the chromosome number, flow cytometry was employed to measure the genome size, and fluorescent in situ hybridization was performed using 45S and 5S ribosomal DNA (rDNA) and the telomeric sequences (TTAGGG)_n and (TTTAGGG)_n as genetic markers. There were proportional increases with ploidy level of the following: (1) chromosome number (from diploid 2n = 2x = 60 to hexaploid 2n = 6x = 180), including the number of large and small chromosomes in the bimodal karyotype of Agave; (2) genome size, with a mean monoploid genome size (1Cx) of 7.5 pg (range, 7.36–7.61 pg); and (3) the number and distribution of 45S and 5S rDNA loci, with one locus of each per basic, monoploid genome. Thus there was complete additivity in genome structure with increasing ploidy, as reported in some angiosperm polyploids. However, as other analyses of polyploids have revealed a decrease in 1Cx values with increased ploidy, possible explanations for the observed genomic stability were considered. With the (TTAGGG)_n probe, the signal was localized at the telomeres, consistent with published data showing that many species in the order Asparagales have this type of telomere sequence. It is speculated that sporadic telomeric signals using the (TTTAGGG)_n probe are probably derived from either errors in telomerase activity or relic ancestral‐type telomeric sequences. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 215–222.     

Checklist of Commelinaceae of Equatorial Guinea (Annobón,Bioko and Río Muni)

A checklist of Commelinaceae of Equatorial Guinea, comprising 46 taxa in 12 genera, is presented. The best represented genus is Palisota, with 11 species. Bibliographical references for Commelinaceae from Equatorial Guinea have been gathered and checked. Eleven species of Commelinaceae are recorded for the first time in the country. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 106–122.     

SOUND PRODUCTION BY THE LUSITANIAN TOAD FISH,HALOBATRACHUS DIDACTYLUS

ABSTRACT

Several batrachoidids have been known to produce sounds associated with courtship and agonistic interactions, and their repertoires have been studied acoustically and behaviourally. In contrast, sound production of the Lusitanian toadfish Halobatrachus didactylus, although often noted, has not been acoustically studied.

This sedentary predator of Northeastern Atlantic coastal waters is usually found in sandy and muddy substrates, under rocks or crevices. Sound recordings were made in Ria Formosa, a lagoon complex in southern Portugal. The sound producing apparatus was studied in adult individuals of both sexes captured by local fishermen.

It is shown that this species produces acoustic emissions similar to other batrachoidids. It produces a long, rhythmical, tonal sound, often in choruses, which is comparable to the boatwhistle or hum signals of Opsanus and Porichthys, and a complex of signals that were classified as grunts, croaks, double croaks and mixed calls (‘grunt-croak’). As in other toadfishes, H. didactylus presents sonic muscles connected to a bi-lobed swimbladder. Asynchronous contractions of the sonic muscles were detected when massaging the ventral surface of the fish.     

Are generalist Aphidiinae (Hym. Braconidae) mostly cryptic species complexes?

Aphidiinae are mostly composed of specialist parasitoids and the few species described as generalist are suspected to be composed of cryptic specialists, almost indistinguishable based on morphological characteristics. The use of molecular markers has proven to be a useful tool for revealing cryptic species complexes and here we use seven mitochondrial and nuclear gene fragments to study possible genetic differentiation among seven Aphidiinae generalists. Maximum likelihood (ML) trees and Bayesian Poisson tree processes (bPTP) models were conducted on each gene separately and on the seven genes together. The standard cytochrome c oxidase I barcode region appeared to be the most polymorphic and probably the best marker to reveal putative cryptic species. However, we showed with ML trees and bPTP models that a complementary use of mitochondrial and nuclear genes was the most relevant approach to reliably identify cryptic genetic clades in the Aphidiinae. Overall, most of the analysed generalist morphospecies were shown to be composed of subgroups related to the aphid host, some of them revealed as cryptic species by the species delimitation analysis. Further studies are needed to reveal the generality of this result in Aphidiinae.     

Isolation and characterization of ten microsatellite loci for Senegal sole (Solea senegalensis Kaup)

Senegal sole (Solea senegalensis Kaup) is a high‐value marine flatfish exploited in both fisheries and aquaculture. Here we describe the isolation of seven tetranucleotide and three dinucleotide polymorphic microsatellite loci. Characteristics of a captive broodstock and a wild population are described. Three loci displayed a significant departure from Hardy–Weinberg expectations in both populations, suggesting a substantial frequency of null alleles. The remaining seven loci were found to be in equilibrium in the wild population, whereas only four of them were in the cultured population. Cross‐species amplification was successful for three loci in other five flatfishes.