Pollen Dispersal in Fragmented Populations of the Dioecious Wind-Pollinated Tree,Allocasuarina verticillata (Drooping Sheoak,Drooping She-Oak; Allocasuarinaceae)

Vegetation clearing, land modification and agricultural intensification have impacted on many ecological communities around the world. Understanding how species respond to fragmentation and the scales over which functionality is retained, can be critical for managing biodiversity in agricultural landscapes. Allocasuarina verticillata (drooping sheoak, drooping she-oak) is a dioecious, wind-pollinated and -dispersed species with key conservation values across southeastern Australia. But vegetation clearing associated with agricultural expansion has reduced the abundance and spatial distribution of this species in many regions. Spatial genetic structure, relatedness among trees, pollen dispersal and mating patterns were examined in fragmented A. verticillata populations selected to represent the types of remnants that now characterise this species. Short scale spatial genetic structure (5–25 m) and relatedness among trees were observed in most populations. Unexpectedly, the two male trees closest to each female did not have a reproductive advantage accounting for only 4–15% of the seed produced in larger populations. Biparental inbreeding was also generally low (<4%) with limited evidence of seed crop domination by some male trees. More male trees contributed to seed crops in linear remnants (mean 17) compared to those from patch remnants (mean 11.3) which may reflect differences in pollen dispersal within the two remnant types. On average, pollen travels ~100 m irrespective of remnant type but was also detected to have dispersed as far as 1 km in open landscapes. Low biparental inbreeding, limited reproductive assurance for near-neighbour and probably related males and variability in the distances over which females sample pollen pools suggest that some mechanism to prevent matings between relatives exists in this species.     

Maturation of Squalus mitsukurii and Cirrhigaleus asper (Squalidae, Squaliformes) in the southwestern equatorial Atlantic Ocean

Specimens of Squalus mitsukurii (n = 206) and Cirrhigaleus asper (n = 93) were opportunistically collected from the catches of a research vessel using traps and benthic longlines off the coast of northeastern Brazil between March 1997 and August 2002. For both species, larger females than males were captured. Catches of S. mitsukurii were biased toward females (1 : 4.6), while no significant disequilibrium in sexes was detected for C. asper (1 : 0.86). Common regressions for total length (TL) and eviscerated weight (EW) were calculated as LnEW = 3.13LnTL − 6.217 (S. mitsukurii) and LnEW = 3.22LnTL − 7.01 (C. asper). Based on changes to the reproductive tract, females and males of each species were categorized into several stages of maturation. Sizes at sexual maturity for female (n = 169) and male (n = 37) S. mitsukurii were 77.8 and 65.0 cm TL, respectively. Gravid S. mitsukurii had between 3 and 11 embryos that ranged in size from 2.0 to 22.5 cm TL (n = 262). No significant bias in the sex ratio of embryos was detected. A clear relationship between embryonic development and maturation of the ovary demonstrated that female S. mitsukurii are ready to ovulate immediately after parturition. Female (n = 43) and male (n = 50) C. asper approached sexual maturity at 110.0 and 91.0 cm TL, respectively. Uterine fecundity in gravid C. asper ranged from 12 to 19 embryos that varied in size between 4.0 and 21.9 cm TL. Unlike S. mitsukurii, there was no concurrent development of the ovary and embryos. The results are discussed in terms of the reproductive plasticity of S. mitsukurii and the need for further life history studies on both species.     

Comparative morphology of the sagittal otolith in Serranus spp.

Variations in the morphology of saccular otoliths (sagittae) among three sympatric species of the genus Serranus ( S. atricauda , S. cabrilla and S. scriba ) from the Canary Islands were investigated. Although the otolith gross morphology was similar among species, S. scriba was distinct in having a rostrum which had a slight turning at the tip and a more funnel‐like ostium. The shallower water species ( S. scriba ) had otolith and sulcus areas which were smaller than the deeper water species ( S. cabrilla and S. atricauda ). The sulcus acusticus and ostium size were correlated with the habit depth of the species, with the highest values in the deepest species, S. cabrilla . The otolith outline shape indices changed with size (total length) of the species, and allowed the separation of the species by means of a discriminate function.     

Consistency of side choice in the milking parlour by Holstein-Friesian cows and its relationship with their reactivity and milk yield

Dairy cows often have to choose which of two sides to enter in the milking parlour. Some cows are very consistent in this choice, and it is common to assume that when these cows are more disturbed are being milked in their non-preferred side. Such disturbance might involve significantly poor welfare. In order to assess this assumption, we decided to study the behaviour and milk yield of dairy cows and their relationships with side preference in the milking parlour. The study was carried out at Cambridge University Farm, in a two-sided tandem milking parlour. The data collection followed the daily management routine. We recorded the side chosen by each cow (left or right) during 40 milking sessions. Data from 70 cows, which were present in at least 25 milking sessions (mode=36), were included in the statistical analysis. Cows' reactivity (CR) during premilking udder preparation, time spent fitting the milking cluster (FT), milk yield (MY) and duration of milking (DM) were measured. There was evident individual variation in the consistency of side choice. Individual differences (ANOVA, P<0.001) were also found in CR, FT, MY and DM; although these variables were not significantly affected by the side or the interaction animalxside (ANOVA, P>0.05). The comparison between left and right side means (paired t-test) of these variables did not show significant differences (P>0.05). We concluded that there is no evidence that the cows were discomforted or stressed when milked in the non-preferred side of the milking parlour.     

Nickel localization and response to increasing Ni soil levels in leaves of the Ni hyperaccumulator Alyssum murale

We have previously developed phytoremediation and phytomining technologies employing Alyssum Ni hyperaccumulators to quantitatively extract Ni from soils. Implementation of these technologies requires knowledge of Ni localization patterns for the Alyssum species/ecotypes of interest under realistic growth conditions. We investigated Ni uptake and localization in mature Alyssum murale Kotodesh and AJ9ç leaves. Seedlings were grown in potting mix with an increasing series of NiSO₄ addition (0, 5, 10, 20, 40, 80 mmol Ni kg^–1), NiC₄H₆O₄ addition (0, 5, 10, 30, 60, 90 mmol Ni kg^–1), in Ni-contaminated soil from metal refining operations, and serpentine soil. Plants at Ni levels 0, 5, 10, 20 mmolkg^–1 and in native soils grew normally. Plants at 40 mmolkg^–1 exhibited the onset of phytotoxicity, and 60, 80, and 90 mmolkg^–1 were demonstrably phytotoxic, but symptoms of phytotoxicity abated within 6 months. Cryogenic complement fractures were made from frozen hydrated samples. High-resolution scanning electron microscope (SEM) images were taken of one half. The other half was freeze-dried and examined with SEM and semi-quantitative energy dispersive x-ray analysis. Ni was highly concentrated in epidermal cell vacuoles and Ni and S counts showed a positive correlation. Trichome pedicles and the epidermal tissue from which the trichome grows were primary Ni compartments, but Ni was not distributed throughout trichomes. Palisade and spongy mesophyll and guard/substomatal cells contained lesser Ni concentrations but palisade mesophyll was an increasingly important compartment as Ni soil levels increased. Ni was virtually excluded from vascular tissue and trichome rays.     

Cytochemical demonstration of hydrogen peroxide in polymorphonuclear leukocyte phagosomes

Phagocytosis by polymorphonuclear leukocytes (PMN) is accompanied by specific morphological and metabolic events which may result in the killing of internalized micro-organism. Hydrogen peroxide is produced in increased amounts during phagocytosis (17) and in combination with myeloperoxidase and halide ions constitute a potent, microbicidal mechanism (8,9,11). There can be direct iodination of micro-organisms (10), or alternatively, other intermediate reaction products, i.e. chloramines and aldehydes (21), can exert a microbicidal effect. The H2O2-peroxidase-halide system is presumed to operate within the phagocytic vacuole (12,18). Myeloperoxidase, present in the primary granules of PMN, enters the phagocytic vacuole during degranulation (1,4,7), and halide ions are probably derived from the extracellular medium or are present in the PMN (see 11, 18). For the operation of this system in intact cells, the presence of H2O2 in the phagocytic vacuole is necessary, and indeed this has been suggested by the work of several investigators (12, 18, 21). In the present investigation, the diaminobenzidine reaction of Graham and Karnovsky (5), modified to utilize endogenous myeloperoxidase and hydrogen peroxide, has been applied to actively phagocytizing PMN to demonstrate cytochemically the presence of H2O2 in the phagocytic vacuole.     

Molecular evolution of P transposable elements in the genus Drosophila. I. The saltans and willistoni species groups

A phylogenetic survey using the polymerase chain reaction (PCR) has identified four major P element subfamilies in the saltans and willistoni species groups of Drosophila. One subfamily, containing about half of the sequences studied, consists of elements that are very similar to the canonical (and active) P element from D. melanogaster. Within this subfamily, nucleotide sequence differentiation among different copies from the same species and among elements from different species is relatively low. This observation suggests that the canonical elements are relatively recent additions to the genome or, less likely, are evolving slowly relative to the other subfamilies. Elements belonging to the three noncanonical lineages are distinct from the canonical elements and from one another. Furthermore, there is considerably more sequence variation, on the average, within the noncanonical subfamilies compared to the canonical elements. Horizontal transfer and the coexistence of multiple, independently evolving element subfamilies in the same genome may explain the distribution of P elements in the saltans and willistoni species groups. Such explanations are not mutually exclusive, and each may be involved to varying degrees in the maintenance of P elements in natural populations of Drosophila.      

A genetic assessment of seed production areas (SPAs) for restoration

The conservation and restoration of degraded landscapes continues to be a major activity with the demand for seed increasing to meet growing global targets. Seed collected from natural plant populations is often irregular and unpredictable, limiting the diversity of species that can be conserved through restoration programs and the area that can be restored. Seed production areas (SPAs; seed orchards, seed increase) are one option for improving seed supply and quality to meet the demand from conservation and restoration programs. We evaluated genetic diversity, inbreeding and mating system parameters in adults and seed from remnants and SPAs of Acacia montana and Dodonaea viscosa subsp. cuneata, two key restoration species in south-eastern Australia. Overall, we found no significant differences in genetic diversity between remnants and SPAs of both species or between adult and seed cohorts. In contrast, we found significant inbreeding in many remnants and their seed crops suggesting that some inbred seed were used to establish these SPAs. We also found significant inbreeding in some SPAs and their seed crops and that SPAs were often biased towards one to two source remnants. Additional germplasm is now required to broaden the representativeness of remnants in the SPAs and the genetic base of seed being produced for restoration programs.     

Effects of barotrauma and mitigation methods on released Australian bass Macquaria novemaculeata

The effects of barotrauma on the short-term mortality and physical condition of Australian bass Macquaria novemaculeata were investigated after being: (1) conventionally angled and released during two tournaments in deep impoundments and (2) released untreated or subjected to venting or recompression during a manipulative experiment. All fish were released into two 20 m deep bathy-cages and monitored for 3 days. Of 238 M. novemaculeata angled during the tournaments, 43 (18·1%) had clinical signs of barotrauma or were vented and five of these later died (11·6% mortality). Catch histories varied significantly between both barotrauma and non-barotrauma fish and tournaments, but only hook ingestion significantly influenced mortality (P < 0·05). During the manipulative experiment, venting significantly influenced mortality (13·3%) compared to no treatment or recompression (no deaths). Magnetic resonance images and dissections of barotrauma fish indicated large variation among clinical signs. On the basis of these results, wherever possible M. novemaculeata suffering barotrauma should be immediately released with no treatment. Fish that are unable to resubmerge should be recompressed, while those held in live wells and released in shallow water should be vented.     

Genetic divergence among and diversity within two rare <Emphasis Type="Italic">Banksia</Emphasis> species and their common close relative in the subgenus<Emphasis Type="Italic">Isostylis</Emphasis> R.Br. (Proteaceae)

The Banskia subgenus Isostylis complex is comprised of two rare and restricted species, B. cuneata and B. oligantha, and the widespread B. ilicifolia. Population genetic structure and genetic diversity were examined within and among the three species using 10 allozyme loci across 21 populations. Levels of genetic diversity did not appear to correspond with either population size or geographic distribution. The restricted species B. cuneata exhibited the highest levels of gene diversity (H _es , 0.13) followed by the widespread B. ilicifolia (H _es , 0.10) and the other restricted species B. oligantha (H _es , 0.08). Similarly, there was no relationship between genetic structure and geographical distribution with the rare B. cuneata being highly structured ( =0.370) compared with B. ilicifolia ( =0.164) and B. oligantha ( =0.221). The relatively low but similar levels of diversity present in the subgenus concur with those observed in other proteaceous genera and probably reflect historical events rather than a genetic effects associated with a recently fragmented landscape.