Variations in bulk leaf carbon isotope discrimination, growth and related leaf traits among three Populus nigra L. populations

The ongoing global change could be an additional threat to the establishment and the long-term survival of Populus nigra L., an emblematic European riparian species. With the general aim of gaining insights into the adaptive potential of this species, we (i) quantified variations within and among three French P. nigra populations for key physiological attributes, i.e., water-use efficiency (assessed from bulk leaf carbon isotope discrimination, Δ(13)C), growth performance and related leaf traits, (ii) examined genotype and population by environment interactions, and (iii) explored the relationship between Δ(13)C and growth. Thirty genotypes were sampled in each of three naturally established populations and grown in two different sites, Orléans (ORL) and Guémené-Penfao (GMN). In ORL, two similar plots were established and different watering regimes were applied in order to test for the drought response. Significant variations were observed for all traits within and among populations irrespective of site and watering. Trait variation was larger within than among populations. The effect of drought was neither genotype- nor population-dependent, contrary to the effect of site. The population ranking was maintained in all sites and watering regimes for the two most complex traits: Δ(13)C and growth. Moreover, these two traits were unrelated, which indicates that (i) water-use efficiency and growth are largely uncoupled in this species, and (ii) the environmental factors driving genetic structuration for Δ(13)C and growth act independently. The large variations found within populations combined with the consistent differences among populations suggest a large adaptive potential for P. nigra.     

Time course of δ1¹³C in poplar wood: genotype ranking remains stable over the life cycle in plantations despite some differences between cellulose and bulk wood

Genetic differences in δ13C (isotopic composition of dry matter carbon) have been evidenced among poplar genotypes at juvenile stages. To check whether such differences were maintained with age in trees growing in plantations, we investigated the time course of δ13C as recorded in annual tree rings from different genotypes growing at three sites in southwestern France and felled at ～15-17 years. Wood cores were cut from tree discs to record the time course of annual basal area increment (BAI). The isotopic ratio δ13C was recorded in bulk wood and in extracted cellulose from the annual rings corresponding to the period 1996-2005. Discrimination against 13C between atmosphere and tissues (Δ13C) was computed by taking into account the inter-annual time course of δ13C in the atmosphere. Annual BAI increased steadily and stabilized at about 8 years. An offset in δ13C of ～1‰ was recorded between extracted cellulose and bulk wood. It was relatively stable among genotypes within sites but varied among sites and increased slightly with age. Site effects as well as genotype differences were detected in Δ13C recorded from the cellulose fraction. Absolute values as well as the genotype ranking of Δ13C remained stable with age in the three sites. Genotype means of Δ13C were not correlated to annual BAI. We conclude that genotypic differences of Δ13C occur in older poplar trees in plantations, and that the differences as well as the genotype ranking remain stable while trees age until harvest.     

Insecticide resistance status of the codling moth Cydia pomonella (Lepidoptera: Tortricidae) from Greece

The codling moth Cydia pomonella L. is controlled mostly with chemical insecticides in Greece and control failures have been reported. However, there are no insecticide resistance studies in the country as yet. We examined the insecticide resistance status of 33 and 38 populations of fifth-instar non-diapausing and diapausing larvae, respectively by applying bioassays, biochemical and DNA diagnostics. Diagnostic concentrations of azinphos-methyl, phosalone, deltamethrin, thiacloprid, fenoxycarb, tebufenozide, methoxyfenozide and diflubenzuron were used in bioassays. Almost all populations showed reduced susceptibility to at least one insecticide and approximately half of them to all insecticides examined compared to a laboratory susceptible strain used as reference. However, only one out of six populations tested showed reduced susceptibility in ovicidal tests with fenoxycarb. Cross-resistances were observed among most insecticides, except from the pairs fenoxycarb–phosalone and thiacloprid–phosalone, in non-diapausing larvae. The more obvious biochemical marker associated with the reduced susceptibility observed in both larval instars was elevated cytochrome P₄₅₀ polysubstrate monooxygenases activity, followed by elevated glutathione-S-transferase activity and reduced carboxylesterases activity. Neither sodium channel nor AChE known resistance mutations were found in any of the approximately 1000 individuals of each larval instar screened with diagnostic PCR. Actions for Integrated Resistance Management and application of alternative control methods are discussed.     

Distribution,abundance, and movements of the bottlenose dolphin (Tursiops truncatus) in the Pelagos Sanctuary MPA (north‐west Mediterranean Sea)

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Apoptosis of ligamentous cells of the cranial cruciate ligament from stable stifle joints of dogs with partial cranial cruciate ligament rupture

OBJECTIVE: To describe the presence and amount of apoptotic ligamentous cells in different areas of partially ruptured canine cranial cruciate ligaments (prCCLs) and to compare these findings with apoptosis of ligamentous cells in totally ruptured cranial cruciate ligaments (trCCLs). ANIMALS: 20 dogs with prCCLs and 14 dogs with trCCLs. PROCEDURES: Dogs with prCCLs or trCCLs were admitted to the veterinary hospital for stifle joint treatment. Biopsy specimens of the intact area of prCCLs (group A) and the ruptured area of prCCLs (group B) as well as specimens from trCCLs (group C) were harvested during arthroscopy. Caspase-3 and poly (ADP-ribose) polymerase (PARP) detection were used to detect apoptotic ligamentous cells by immunohistochemistry. RESULTS: No difference was found in the degree of synovitis or osteophytosis between prCCLs and trCCLs. No difference was found in degenerative changes in ligaments between groups A and B. A substantial amount of apoptotic cells could be found in > 90% of all stained slides. A correlation (r(s) = 0.71) was found between the number of caspase-3-and PARP-positive cells. No significant difference was found in the amount of apoptotic cells among the 3 groups. No significant correlation could be detected between the degree of synovitis and apoptotic cells or osteophyte production and apoptotic cells. CONCLUSIONS AND CLINICAL RELEVANCE: The lack of difference between the 3 groups indicates that apoptosis could be a factor in the internal disease process leading to CCL rupture and is not primarily a consequence of the acute rupture of the ligament.     

Use of a biosynthetic material to repair the surgical defect following excision of an epibulbar melanoma in a cat

A limbal melanoma was surgically excised from the OS of a 4-year-old castrated male Domestic Short-haired cat (DSH). The resultant scleral defect was repaired by placement of A-cell bio-scaffold material. The patient responded well in the postoperative period with no apparent discomfort, nor any observable complications. No signs of recurrence have been evident nearly 2.5 years following surgical removal. A-cell appears to be a safe and reasonable option to lend support to corneoscleral defects following removal of neoplastic lesions. It carries with it the advantages of availability, minimal host rejection, and reduced potential for iatrogenic spread of infections agents.