Different behavior of phagocytes in young and old subjects]

Ageing is a dynamic phenomenon in which there is a physiological decay in all the functions of the individual. The consequence is an increased susceptibility to infections, autoimmune diseases and cancer. Phagocytic cells as polymorphonuclear leukocytes (PMNL) and monocytes (Mo) are of prime importance in the defence against invasive agents, PMNL and Mo seek out and destroy invading micro-organisms. Chemotaxis and phagocytosis are two mechanisms that are activated by these cells for this purpose. In this study, using "in vitro" techniques, we have verified if, at the level of such functions of cell defense, there could be variations in elderly subjects with respect to younger subjects. Our results show a chemotactic activity of PMNL in the elderly that is higher and a phagocytic activity that is lower. As regards Mo, there is a lower chemotactic activity in the elderly and only a slight difference in phagocytic activity with respect to the younger subjects. These results are in agreement with those found at the clinical level showing the elderly less protected from infection with respect to younger subjects.     

Effects of resource availability on seedling recruitment in a fire-maintained savanna

The herbaceous ground cover of the longleaf pine ecosystem harbors the highest plant species richness in North America, with up to 50 species per square meter, but the mechanisms that regulate this diversity are not well understood. In this system, variability in seedling recruitment events may best explain the extremely high small-scale species richness and its relationship to soil moisture and system net primary productivity. To understand the potential mechanistic controls on species richness, we used a long-term resource manipulation study across a natural soil moisture gradient to assess environmental controls on seedling recruitment. We considered the availability of resources to be an indicator of seedling safe-site supply, and also manipulated seed availability to examine the relative importance of recruitment limitations on seedling diversity. We found that water availability regulated the number of species in the seedling community regardless of the underlying natural moisture gradient, and that this effect may result from differential responses of seedling guilds to resource availability. Water supply was more important than seed supply in determining seedling establishment, suggesting that appropriate sites for regeneration are a factor limiting seedling success. This is the first study that shows that the episodic supply of microsites for recruitment could influence species richness in the highly threatened and biodiverse longleaf pine savanna.     

Estimating realistic costs for strategic management planning of invasive species eradications on islands

Environmental managers regularly face decisions about how to counteract threats. These decisions require an understanding of both the conservation benefits and economic costs of candidate actions. However, transparent frameworks for how to accurately calculate costs for management are rare. We worked with island managers in Australia to develop eradication protocols for six invasive species- four mammals and two weeds. We used the protocols to create an accounting framework for invasive species eradications to produce realistic cost estimates for eradications across multiple locations. We also used our models to test common cost assumptions: (1) that costs scale linearly with area, (2) that terrain does not influence costs, and (3) that eradication costs stay constant through time. By explicating testing assumptions, we found that costs largely scaled linearly with area, that terrain influences costs, and that costs decline as populations decline in response to ongoing management. Estimated mammal eradication costs were driven in large part by the area of an island and the cost of transport. However, when area alone was used as a proxy for costs, the calculated costs deviated from our modelled costs by 40–56%. Weed eradication cost estimates were driven by the size and density of an infestation as well as the terrain of the island, with the effect of terrain becoming more pronounced as area to be treated increased. We provide a method to calculate realistic costs across several sites, which can be used to guide strategic management decision-making, including prioritisation, and on-ground management actions.     

Study of rhizosphere and phyllosphere bacterial community and resistance to bacterial canker in genetically engineered phytochrome A cherry plants

The cherry rootstock 'Colt' line was transformed with a phytochrome A rice gene with the aim of altering light perception. Three transgenic events were chosen because of a modified developmental behavior. When red enriched light was supplied horizontally to stems, the PD3 transgenic line showed an increased rate of phytomer formation associated to a superior rate of plant growth compared to wild type (WT). Under the same light conditions, the PO1 and PA lines were less altered in morphology and development. When far-red enriched light was supplied, all transgenic lines had a reduced rate of growth, with the PD3 line being the most similar to the WT. The influence of the alien gene on root and leaf-associated bacteria was studied for a duration of 1 year. Significantly more culturable bacteria were recovered from PA lines than from PO1, PD3 and WT lines. On average, significantly more fluorescent pseudomonads were recovered from the rhizosphere of PA and PO1 lines than from PD3 and WT. No significant differences were detected in the number of bacteria recovered from the phyllosphere of transgenic and WT plant lines. A total of 143 Pseudomonas fluorescens strains isolated from rhizosphere of transgenic and WT lines were tested for their antagonistic activity against Phytophthora nicotianae and differences between bacteria derived from transgenic and WT were not detected. Fluorescent pseudomonads strains isolated from phyllosphere of PA and PO1 lines showed antagonistic activity against P. syringae pv. syringae, whereas no difference among the transgenic and WT lines was detected when fluorescent Pseudomonas strains were tested against P. syringae pv. mors-prunorum. Pathogenicity tests were conducted on rooted and micropropagated plants with P. s. pv. syringae and P. s. pv. mors-prunorum: in all assays, the PO1 lines were the most tolerant to P. s. pv. Syringae, and the PO1 and PD3 were tolerant to P. s. pv. mors-prunorum.     

A New Somaclone of Prunus Avium Shows Diverse Growth Pattern under Different Spectral Quality of Radiation

The aim of this research was to set up a regeneration protocol from mature explants of Prunus avium L. cv. Hedelfinger and to develop an early screening method for selection of putative somaclones based on morphological and physiological traits regulated by the spectral quality of radiation. DNA analyses of a new somaclone named HS, conducted using Inter Simple Sequence Repeat (ISSR), revealed a polymorphism between the somaclone HS and wild type propagated by microcuttings. When grown under different spectral quality of radiation, somaclone HS showed a different pattern of growth and development compared to the wild type with the main modifications related to apical dominance and chlorophyll production. Somaclone HS showed reduced apical dominance compared to the wild type. Wild type shoots grown in darkness showed chlorophyll a and b contents at levels in both cases comparable to those recorded under red radiation while HS did not retain the same capability.     

Using structured decision‐making to set restoration objectives when multiple values and preferences exist

Achieving global targets for restoring native vegetation cover requires restoration projects to identify and work toward common management objectives. This is made challenging by the different values held by concerned stakeholders, which are not often accounted for. Additionally, restoration is time‐dependent and yet there is often little explicit acknowledgment of the time frames required to achieve outcomes. Here, we argue that explicitly incorporating value and time considerations into stated objectives would help to achieve restoration goals. We reviewed the peer‐reviewed literature on restoration of terrestrial vegetation and found that while there is guidance on how to identify and account for stakeholder values and time considerations, there is little evidence these are being incorporated into decision‐making processes. In this article, we explore how a combination of stakeholder surveys and workshops can be used within a structured decision‐making framework to facilitate the integration of diverse stakeholder values and time frame considerations to set restoration objectives. We demonstrate this approach with a case of restoration decision‐making at a regional scale (southeast Queensland, Australia) with a view to this experience supporting similar restoration projects elsewhere.     

Experimental test for facilitation of seedling recruitment by the dominant bunchgrass in a fire-maintained savanna

Facilitative interactions between neighboring plants can influence community composition, especially in locations where environmental stress is a factor limiting competitive effects. The longleaf pine savanna of the southeastern United States is a threatened and diverse system where seedling recruitment success and understory species richness levels are regulated by the availability of moist microsites. We hypothesized that the dominant bunch grass species (Aristida stricta Michx.) would facilitate moist seedling microsites through shading, but that the effect would depend on stress gradients. Here, we examined the environmental properties modified by the presence of wiregrass and tested the importance of increased shade as a potential facilitative mechanism promoting seedling recruitment across spatial and temporal stress gradients. We showed that environmental gradients, season, and experimental water manipulation influence seedling success. Environmental properties were modified by wiregrass proximity in a manner that could facilitate seedling success, but we showed that shade alone does not provide a facilitative benefit to seedlings in this system.     

The effect of light quality on anther culture of <Emphasis Type="Italic">Citrus clementina</Emphasis> Hort. ex Tan.

This preliminary research reports results on the influence of light quality on anther culture of Citrus clementina Hort. ex Tan., cultivar Nules. After one month of cultivation in darkness, four light qualities were tested: White, Red, Far-Red and Blue. Continuous Darkness and White light under photoperiod of 16 hrs were used as a control conditions. Gametic embryoids and embryogenic callus were obtained only under photoperiodic conditions of White light, suggesting that the alternation of light and dark can be used for the process of gametic embryogenesis in Citrus.