Changes in leaf water relations, gas exchange, growth and flowering quality in potted geranium plants irrigated with different water regimes

Geranium plants are an important part of urban green areas but suffer from drought, especially when grown in containers with a limited volume of medium. In this experiment, we examined the response of potted geraniums to different irrigation levels. Geranium (Pelargoniumxhortorum L.) seedlings were grown in a growth chamber and exposed to three irrigation treatments, whereby the plants were irrigated to container capacity (control), 60% of the control (moderate deficit irrigation, MDI), or 40% of the control (severe deficit irrigation, SDI). Deficit irrigation was maintained for 2 months, and then all the plants were exposed to a recovery period of 112 month. Exposure to drought induced a decrease in shoot dry weight and leaf area and an increase in the root/shoot ratio. Height and plant width were significantly inhibited by the SDI, while flower color parameters were not affected by deficit treatment. The number of wilting and yellow leaves increased, coinciding with the increase in the number of inflorescences and open flowers. Deficit irrigation led to a leaf water potential of about -0.8MPa at midday, which could have caused an important decrease in stomatal conductance, affecting the photosynthetic rate (Pn). Chlorophyll fluorescence (Fvm) values of 0.80 in all treatments throughout the experiment demonstrate the lack of drought-induced damage to PSII photochemistry. Pressure-volume analysis revealed low osmotic adjustment values of 0.2MPa in the SDI treatment, accompanied by increases in the bulk tissue elastic modulus (epsilon, wall rigidity) and resulting in turgor loss at lower leaf water potential values (-1.38MPa compared with -1.0MPa for the control). Leaf water potential values throughout the experiment below those for Psitlp were not found at any sampling time. By the end of the recovery period, the leaf water potential, stomatal conductance and net photosynthesis had recovered. We infer from these results that moderate deficit irrigation in geranium reduced the consumption of water, while maintaining the good overall quality of plants. However, when SDI was applied, a reduction in the number of flowers per plant was observed.     

Effect of conjugated linoleic acid on dietary lipids utilization, liver morphology and selected immune parameters in sea bass juveniles (Dicentrarchus labrax)

Increased energy content in fish feeds has led to an enhanced fat deposition, particularly in European sea bass, concerning fish farmers. Inclusion of conjugated linoleic acid (CLA) could reduce fat deposition as in other vertebrates. To determine if dietary CLA affects fat deposition, lipid metabolism, lipid composition and morphology of different tissues, growth and selected immune parameters, European sea bass juveniles were fed 4 graded levels of CLA (0, 0.5, 1 and 2%). Growth and feed conversion were not affected by CLA, whereas feed intake was reduced (P < 0.05) by feeding 2% CLA. In these fish perivisceral fat was also reduced (P < 0.05), particularly reducing (P < 0.05) monounsaturated fatty acids. CLA has not affected tissue proximal composition, but reduced (P < 0.05) saturated and monounsaturated fatty acids and increased (P < 0.05) the n−3 and n−3 highly unsaturated fatty acids in muscle and increase (P < 0.05) CLA content in muscle, liver and perivisceral fat. A progressive reduction in lipid vacuolization of hepatocytes cytoplasm and regular-shaped morphology was found in fish fed increased CLA levels, together with a progressive increase in malic enzyme activity (only significant in fish fed 1% CLA). Finally, inclusion of CLA up to 1% increased (P < 0.05) plasma lysozyme activity and was positively correlated with alternative complement pathway.     

Rare sesquiterpenes from South African Pteronia species

The genus Pteronia consists of approximately 80 species which are widely distributed in southern Africa. The essential oils isolated from the aerial parts of eleven species, analyzed by GC-MS varied both qualitatively and quantitatively. In Pteronia pallens, Pteronia empetrifolia and Pteronia flexicaulis uncommon sesquiterpenes such as presilphiperfolol-7-ene, 7-α-(H)-silphiperfol-5-ene, 7-β-(H)-silphiperfol-5-ene, α-campholene aldehyde, silphiperfol-5-ene, cameroonan-7-α-ol, silphiperfol-7-β-ol, presilphiperfolan-9-α-ol and presilphiperfolan-8-ol (a major compound in P. pallens) were identified. Cluster analysis based of the chemical composition of the oils revealed that individual plants of Pteronia camphorata collected in the same population had similar oil profiles with a high correlation coefficient (S_corr ≈ 0.98). Similarly, the essential oil composition of P. pallens collected from two distinct localities also showed high levels of congruency (S_corr ≈ 0.99).     

Prion Protein Polymorphisms and Estimation of Risk of Scrapie in East Asian Sheep

Allele and genotype frequency distributions of prion protein (PrP) polymorphisms at three codons, 136, 154, and 171, in East Asian sheep were determined by PCR–RFLP analysis using 553 animals from nine local breeds of the northern group and four local breeds of the southern group. Based on the genotype distribution, the risk score for scrapie was estimated. Among the local breeds, ARQ appeared predominantly (0.7701–1), followed by ARH and ARR. From such a biased allele distribution, it was difficult to ascertain the prevalent genetic relationships. A marked difference in allele frequencies between the northern and southern groups was seen (P < 0.0001). The East Asian sheep had ARQ at the highest frequency (0.8834); in European sheep it was 0.5317. According to an assessment of scrapie risk in the PrP genotype classes, the predominant ARQ/ARQ in East Asian sheep corresponded to the risk score of R4. This finding suggests that East Asian sheep have a high level of genetic susceptibility to scrapie.     

Canine visceral leishmaniasis caused by Leishmania infantum in Senegal: risk of emergence in humans?

In the context of global warming and the risk of spreading arthropod-borne diseases, the emergence and reemergence of leishmaniasis should not be neglected. In Senegal, over the past few years, cases of canine leishmaniasis have been observed. We aim to improve the understanding of the transmission cycle of this zoonosis, to determine the responsible species and to evaluate the risk for human health. An epidemiological and serological study on canine and human populations in the community of Mont Rolland (Thiès area) was conducted. The data showed a high seroprevalence of canine leishmaniasis (>40%) and more than 30% seropositive people. The dogs’ seroprevalence was confirmed by PCR data (concordance > 0.85, Kappa > 0.7). The statistical analysis showed strong statistical associations between the health status of dogs and seropositivity, the number of positive PCRs, clinical signs and the number of Leishmania isolates. For the first time, the discriminative PCRs performed on canine Leishmania strains clearly evidenced that the pathogenic agent is Leishmania infantum. The results obtained show that transmission of this species is well established in this area. That the high incidence of seropositivity in humans may be a consequence of infection with this species is discussed.     

Is <Emphasis Type="Italic">Gammarus tigrinus</Emphasis> (Crustacea,Amphipoda) becoming cosmopolitan through shipping? Predicting its potential invasive range using ecological niche modeling

While the intensity of global shipping has increased dramatically over the last decades, species exchange between continents has likewise intensified. Ballast water of ships is recognized playing a major role in this process. Many of the larger sea ports have become bridgeheads for invasions. Ecological niche modeling is used to investigate the potential invasive range and high invasive risk ports of the North American amphipod Gammarus tigrinus. Sixty-two occurrences of G. tigrinus in its native range (North America) and 34 environmental data sets were compiled. Data on dispersal distances were used via ecological niche modeling to analyze the invasive potential of G. tigrinus. The invasive risk of large ports was analyzed according to modeling result, as well as their salinity in the main oceanic routes of the world. G. tigrinus had a rapid range extension on the British Isles and in the rest of Western Europe. Now it is invading the countries surrounding the Baltic Sea. Worldwide it has a vast potential invasive range. It has a high invasive risk for many large ports along the main oceanic routes, among which the ports of Shanghai, Buenos Aires and Montevideo have the highest invasive risk. G. tigrinus may become cosmopolitan through shipping, and this possibility is increasing. Particular emphasis should be placed on preventing human-mediated dispersal. Ports may be the first places G. tigrinus invades. This study can identify high invasive risk ports, especially those at risk of introduced North America species. More importantly, the water of large ports should be monitored regularly for exotic aquatic organisms that may survive temporarily or permanently.     

Evaluating the tolerance of young hybrid poplar trees to recycled waters high in salinity and boron

The successful adoption of water recycling strategies in many arid regions will require crops able to tolerate poor-quality waters. We evaluated different clones for salt and boron (B) tolerance within each of seven genetically distinct genomic groups (e.g., deltoides, deltoides x nigra, trichocarpa x deltoides, trichocarpa x deltoides x maximowizcii, trichocarpa x deltoides x nigra, trichocarpa x nigra, trichocarpa x maximowizcii). During each evaluation period, different clones within each of the groups were irrigated with high sodium chloride (NaCl) salinity (i.e., 10-30 dS m(-1)) and B (i.e., 10 mg L(-1)) water up to a maximum of 150 days, for a 4-year testing period under micro-field plot conditions. Excessive accumulation (up to 6%) of chloride (Cl) likely caused toxicity symptoms (necrosis of the leaves) observed in the less tolerant clones, while leaf B concentrations rarely exceeded 300 mg kg(-1) DM in any clone. Increased soil salinity likely hindered the uptake of B by the clones. Our results show that a wide range of selected Populus clones, of parentage trichocarpa x nigra, followed by deltoides x nigra show potential salt and B tolerance as young trees to recycled waters high in salinity and B.