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- Author or Editor: Peter A. Bishop x
To determine if postharvest treatments of 1-methylcyclopropene (1-MCP) retard the senescence of highbush blueberries (Vaccinium corymbosum L.) removed from storage, `Burlington' (early) and `Coville' (late) fruit were harvested from four experimental sites and treated for 24 hours at 20 °C with 0 (control), 25 (low), 100 (medium), or 400 (high) nL·L-1 of 1-MCP. All fruit were then stored in a controlled atmosphere of 10-15 kPa O2 and 10 kPa CO2 at -1 to 1 °C for 4, 8, and 12 weeks, followed by a 20 °C shelf-life of up to 20 days. During the shelf-life period immediately after harvest and those following each storage removal, percent marketable fruit (PMF) were calculated daily as: [fruit in good condition]/[total berry number] × 100. Changes in PMF were not affected by 1-MCP treatment; hence, we conclude that 1-MCP at rates up to 400 nL·L-1 does not alter the shelf-life quality of the highbush blueberry cultivars tested.
Greenhouse tomato (Lycopersicum esculentum Mill.) producers are urged to reduce their environmental footprint. Here, the suitability of biochar produced from tomato crop green waste as a substrate for soilless, hydroponic tomato production was evaluated. Substrates containing different combinations of biochar (BC) and pine (Pinus radiata D. Don) sawdust (SD) were produced (BC0-SD100, BC25-SD75, BC50-SD50, BC75-SD25, and BC100-SD0) and characterized. The effect of these substrates on tomato growth, yield, and fruit quality was studied. Most of the measured properties of substrates containing biochar were suited to use as a soilless substrate. The electrical conductivity (EC) of substrates containing biochar was initially high (>4.6 mS·cm−1), but was easily reduced to <0.5 mS·cm−1 by rinsing with water before use. The pH of substrates containing biochar was higher than is considered acceptable for tomato production (7.5–9.3) but did not significantly (P < 0.05) affect any plant growth, yield, and fruit quality indicators measured compared with those of plants grown in pine sawdust. The results support the concept of creating a closed loop system whereby biochar produced from tomato crop green waste is used as a substrate for soilless, hydroponic tomato production, providing a sustainable means to support the growth of high-value food crops.
We have developed a Nuclear Magnetic Resonance (NMR)-based approach to metabolomics research that enables the identification of bioactive compounds in crude plant extracts. For this work, we used black raspberries, which are known to contain compounds that exhibit chemopreventive activity toward oral, esophageal, and colon cancers. To ascertain bioactive components and their interrelationships, NMR results for black raspberry samples from four cultivars grown on commercial farms in Ohio were examined using principal component analysis. Multivariate analysis that included anthocyanin content (HPLC), antioxidant activity (DPPH, ABTS, FRAP), total phenolics (Folin-Ciocalteau assay), and bioactivity as measured by inhibition of colon cancer HT-29 cell line proliferation showed correlations with specific regions of NMR spectra at 400 MHz. Correlations were also observed for major and minor groupings of the black raspberry samples. Replicate black raspberry samples were examined with a 750 MHz NMR spectrometer equipped with a cryoprobe that provided a 4- to 5-fold improvement in sensitivity. In this manner, even minor bioactive components in black raspberries could be examined to determine additive and synergistic effects.