Il prohexadione-calcio induce in pomacee la neosintesi di una nuova fitoalessina: il luteoforolo).

Il luteoforolo, una 3-deossiantocianina, indotta dal trattamento con prohexadione-calcio (ProCa) è stata testata in vitro per la sua attività antimicrobica verso numerosi patogeni vegetali. Tale composto ha inibito significativamente la crescita microbica in tutti i batteri ed i funghi presi in considerazione. Inoltre, il luteoforolo si è dimostrato in grado di ridurre lo sviluppo dei sintomi del colpo di fuoco batterico in un test su frutti di pero immaturi

PROHEXADIONE-CALCIUM INDUCES IN APPLE THE BIOSYNTHESIS OF LUTEOFOROL, A NOVEL FLAVAN 4-OL, WHICH IS ACTIVE AGAINST ERWINIA AMYLOVORA

Systemic acquired resistance (SAR) inducers and dioxygenase-inhibitors represent an alternative approach for controlling fire blight. Acibenzolar-S-methyl (ABM), prohexadione-Ca (ProCa) and trinexapac-ethyl (TrixE) were tested in vitro and under field conditions for their efficacy in reducing fire blight incidence and severity. Under field conditions, these compounds significantly reduced (up to 40%) fire blight incidence. Similarly, in vitro, resistance inducers slowed down the pathogen migration in both the xylem and the parenchyma. In particular, the application of ProCa and TrixE resulted in a 50-60% reduction of pathogen migration inside the plant tissues

Estimating Field Metabolic Rates of pinnipeds: Doubly-labelled water gets the seal of approval

1. Measures of the field metabolic rate of marine mammals are extremely difficult to make but they are essential for assessing the impacts of marine mammals on prey populations, and for assessing dive performance in relation to aerobic limits.2. The doubly labelled water (DLW) method is an isotope-based technique for the estimation of the CO2 production, and hence energy expenditure, of free-living animals. Estimates of field metabolic rate (FMR) from DLW in pinnipeds to date are extremely high and at the upper range for most mammals. DLW has previously been validated in pinnipeds but logistical difficulties meant for these validations were less than ideal, and it has been hypothesised that DLW may overestimate FMR in these animals.3. To test this hypothesis, we used DLW and simultaneous open-flow respirometry to determine the daily energy expenditures (DEE) of wild grey seals (Halichoerus grypus) held temporarily in a captive facility, during 4-5 days of simulated foraging at sea. Comparing DEE from DLW and respirometry, we found that DLW predicted DEE accurately (average difference between the two estimates was 0.7% SD = 17% n = 31), but as with validations of other species there was a large range of individual errors (from -39% to +44%).4. The results dispel the doubts surrounding the use of DLW as a field method for estimating energy expenditure in grey seals, and by implication other pinnipeds, and simultaneously open a series of questions about their ability to maintain surprisingly high metabolic rates for protracted periods.5. We make a number of recommendations for future studies of pinniped FMR using DLW. We suggest use of the Speakman two-pool calculation will be most appropriate. Studies should aim for enrichment levels as high as economically feasible but to at least 150 p.p.m. above background for the O-2 isotope. Measurement periods should be extended between one and two half-lives (5-10 days for a typical foraging seal). We also encourage the calculation and presentation of estimates of precision in estimates of FMR.</p