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  • Author or Editor: D. L. Ingram x
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Abstract

Increased soil moisture stress reduced growth and transpiration rate of Ficus benjamina. Leaf drop during indoor phase was greater for plants previously watered during production at 3 day intervals than for plants grown under the 6- and 9-day water regimes.

Open Access

Organic and low-input production systems are increasingly of interest in medicinal plant production, such as Calendula officinalis, a medicinal plant grown for essential oils. However, in these systems the effects of nutrient availability and water stress may act singularly or in combination to affect plant growth and medicinal compound production. This study investigated the effects of organic and conventional fertility sources and drought stress effects on four calendula cultivars. Soil nitrogen (N) status, plant growth, productivity, and essential oil quality and quantity were measured. The plant growth response to increased N availability varied by cultivar, indicating that some cultivars may be better suited to low-input fertility regimes. Fertility source did not significantly affect essential oil quality or quantity. Drought stress reduced plant growth but increased the quality of essential oil, as indicated by the concentrations of specific constituents, although it did not reduce total oil yield. These results indicate that organic and low-input farming systems may significantly reduce plant growth, but may not necessarily affect essential oil yield or quality. As such, the sustainability of medicinal plant production systems may be improved by reductions in water and conventional fertilizers without significant reductions in medicinal compound production.

Free access

Abstract

Silvernerve plant (Fittonia verschaffeltii ssp. argyroneura Coem.), a chill-sensitive foliage plant, was subjected to 2°, 5°, and 8° ± 1°C for 0, 2, 4, or 8 hours. Chilling temperatues caused leaf wilt, inflorescence collapse and brown necrotic spots on the foliage. Severity of chill damage increased with temperature reduction and duration.

Open Access

Much fresh-cut apple research has focused on browning, yet little sensory and flavor analysis has been performed. We therefore evaluated postharvest and flavor changes in stored fresh-cut `Gala' apples prepared after harvest or after CA storage (3 months, 1.4% CO2 and 3% O2). Apples were washed, cored, sliced, dipped in browning inhibitors (BI; Na-erythorbate + CaCl2), packaged in LLDPE bags, and evaluated for descriptive flavor attributes, GC volatiles, firmness, CO2 and O2 and color after 0, 2, 7, and 14 days at 1 °C. Initial apple firmness pre-CA vs. post-CA was 38.3N and 32.7N. Bag O2 concentration dropped to 1% to 2% by day 14 and day 7 for pre- vs. post-CA, respectively. CO2 concentration in bags increased linearly through day 14 in both pre- and post-CA. All pre-CA Hunter L values were higher than post-CA for all treatments on all sampling days. Both BI treatments maintained color for 14 days, but freshly cut (FC) wedges were generally superior whereas stored untreated fresh-cut (SFC) wedges browned markedly by day 2. There was no apparent difference between BI levels in terms of browning or flavor. BI-treated wedges were rated more astringent than FC and SFC, especially after CA. With few exceptions, “fruity”, “raw/ripe apple,” and “sweet” attributes were higher in all pre- vs. post-CA treatments. This trend was conserved through 14 days of storage per treatment. “Sour” and “citrus” scores were higher after CA only in BI-treated wedges. Major compounds recovered were butanol, butyl acetate, hexanol, 2-methylbutyl acetate, amyl/isoamyl acetate, hexyl acetate, 2-hexenyl acetate, butyl 2-methylbutanoate, butyl hexanoate, hexyl butanoate, hexyl 2-methylbutanoate, hexyl hexanoate, isobutyl octanoate and α-farnesene. Flavor-related compounds varied markedly through storage and after CA. The GC volatile analysis will be presented along with any possible correlation to trained sensory evaluations.

Free access

Freezing tolerance and the lethal freezing temperature were determined for detached leaves of avocado (Persea americana Mill.) by either electrolyte leakage or visual appearance of browning. Leaves from field-grown trees of `Gainesville', `Booth8', and `Winter Mexican' in both Gainesville and Homestead, Fla., were evaluated. All cultivars in both locations survived ice formation in their tissue. Leaf tissue had a temperature limit (lethal freeze temperature) at and below which the tissue died. The lethal freezing temperature varied from -5.1 to -9.3C, depending on time of year and location. The lethal freeze temperature for a cultivar decreased over the fall and winter as temperatures decreased. Leaves of `Booth-8' and Winter Mexican' decreased 2.5 and 1.5C, respectively, in Homestead from 13 Nov. 1982 to 5 Feb. 1983. The plants growing at the lower temperature location (Gainesville) had lower lethal freeze temperatures. Leaves of `Gainesville' had a lethal freeze temperature of - 9.3C from trees at Gainesville and - 7.8C from trees at Homestead.

Free access