BACKGROUND: The marketability of bananas over long distances has been limited due to their highly perishable nature and sensitivity to ethylene. To increase the shelf-life several alternatives have been tested in attempts to maintain quality characteristics. We evaluated the effects of 1-methylcyclopropene (SmartFresh SM , 1-MCP) and a chitosan-based edible coating (FreshSeal  , EC), applied alone or combined, on bananas at ripeness stage 3. All fruits were stored for 8 days at 22• C, 85% RH. Color development, weight loss, firmness, physiological, sensory and chemical variables were evaluated.

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The effects of hydrogen cyanamide (H2CN2) on budbreak and phytotoxicity of l-year-old potted peach trees [Prunus persica (L.) Batsch. cv. Redhaven] over a wide range of concentrations at several stages of dormancy were studied. Endodormancy (180° GS; degree growth stage) began on 1 Oct. Maximum intensity of endodormancy (270° GS) was reached after the plants were exposed to 320 chill units on 1 Nov., and 50% of the buds were broken at 860 chill units on 1 Dec. Five concentrations of H2C N2 (0, 0.125, 0.25, 0.5, and 1.0 m) were applied on 1 and 15 Oct., 1 and 15 Nov., and 1 and 15 Dec. 1990. All concentrations promoted budbreak; however, percent budbreak and phytotoxicity depended on concentration and timing of application. The most effective concentration (greatest budbreak and lowest phytotoxicity) was 0.125 m H2CN2 on all treatment dates. Phytotoxicity was evident at all application dates but was greatest at the highest concentrations. Plants were most resistant to H2CN2 at maximum intensity of endodormancy. Hydrogen cyanamide-induced budbreak was highest during the later stages of endodormancy (295 to 315° GS). Treatments applied during the ecodormancy stage (340° GS) inhibited and delayed budbreak and damaged buds and stems. Chemical name used: hydrogen cyanamide (H2CN2, Dormex).

Glutathione content was determined in buds of peach (Prunus persica L.) trees during rest development and release. Reduced (GSH) and oxidized (GSSG) glutathione content changed with the accumulation of chill units (CU). GSH content decreased in the early phases of rest, and then increased at maximum rest. GSH content continued to increase and peaked on 1 Dec at 860 CU, and then dropped during the quiescent stage. It appears that the increase of GSH during chilling was closely associated with the breaking of rest. In contrast GSSG showed a continuous increase from Oct to Dec. Five concentrations of cyanamide were applied every 2 weeks from Oct to Dec. All cyanamide treatments depleted GSH within 12 hr followed by a large increase 24 hr after treatment. The changes in GSH content induced by cyanamide were inversely related to the concentration. The extent of GSH change was dependent on both the physiological status of the bud and the cyanamide concentration. At maximum rest, the plants were more resistant to cyanamide treatment and this coincided with the highest level of cyanamide-induced GSH.

Influenced by feedstock type and microbial inoculum, different microbial groups must precisely interact for high‐quality biogas yields. As a first approach for optimization, this study aimed to identify through time the biogas‐producing microbial community in a 10‐ton dry anaerobic digester treating cattle manure by denaturing gradient gel electrophoresis (DGGE) and metagenomics. Moreover, the associated bovine residues or feedstocks (leachate, manure, oxidation lagoon water, rumen) were also characterized to determine their contribution. A diverse and dynamic community characterized by Bacteria (82%–88%) and a considerable amount of Archaea (8%–15%) presented profiles particular to each stage of biogas production. Eukaryotes (2.6%–3.6%), mainly fungi, were a minor but stable component. Proteobacteria represented 47% of the community at the start of the run but only 18% at the end, opposite to the Bacteroidetes/Chlorobi group (8% and 20%, respectively), while Firmicutes (12%–18%) and Actinobacteria (12%–32%) remained relatively constant. Methanogens of the order Methanomicrobiales represented by several species of Methanoculleus were abundant at the end of the run (77%) contrary to Methanosarcinales (11%) and Methanobacteriales (0.7%). Therefore, methanogenesis mainly occurred by the hydrogenotrophic pathway. Manure and oxidation lagoon water seemed to contribute key microorganisms, while rumen dominated by Methanobrevibacter (72%) did not proliferate in the digester. Manure particularly possessed Methanoculleus (24%) and uncultured methanogens identified by DGGE, whereas oxidation lagoon was exclusively abundant in Methanolinea (18%) and Methanosaeta (19%). Leachate, as the microbial inoculum from a previous run, adequately preserved the biogas‐producing community. These results could lead to higher biogas yields through bioaugmentation strategies by incorporating higher proportions or an enriched inoculum from the relevant feedstocks.