A treatment to inhibit browning and maintain quality of fresh-cut `Anjou' and `Bartlett' pears (Pyrus communis L.) was developed. Slices of ŒAnjou, and ŒBartlett, pears with a range of initial firmness values were dipped in mixtures of 4-hexylresorcinol, isoascorbic acid, potassium sorbate, and N-acetylcysteine before refrigerated storage. Browning, as indicated by visual observation and by colorimeter readings, was inhibited for 14 d. Pears receiving the antibrowning treatment maintained firmness as well or better than the control slices.
Treatment of mango (Mangifera indica cv Kent) with methyl jasmonate (MJ) vapor for 20 h at 20 °C was effective in reducing chilling injury (CI) symptoms and decay, and enhancing skin color development. MJ (10-4 M) was the most effective concentration for reducing CI and decay in fruit stored at 5 °C followed by 7 days at 20 °C (shelf life period). The use of 10-5 M MJ enhanced yellow and red color development of mango kept at 20 °C. These fruit possessed higher L*, a* and b* values than controls and those treated with 10-4 M MJ. Ripening processes were inhibited by cold storage in control fruits. After cold storage (5 °C) and the shelf life period, fruit treated with 10-5 M MJ fruit ripened normally and contained the highest total soluble solids (TSS). These fruit maintained higher sugar and organic acid levels than those in other treatments. We concluded that MJ treatment could be used to reduce decay and CI symptoms, and also to improve color development of mango fruit without adversely affecting quality.
A 5-minute dip in a suspension of camptothecin, a naturally occurring growth regulator, at 5×10–2 mM or at higher concentrations inhibited both adventitious root growth and top sprouting of partially trimmed (tops trimmed to 5 mm) radishes (Raphanus sativus L., cvs. Comet and Stop Light) during 2 weeks of storage at 10° or 20°C. The treatment also reduced weight loss but did not affect changes in red color or ascorbic acid content. Camptothecin was ineffective in inhibiting sprouting when tops were trimmed to 25 mm. Radishes stored at 0° had no new root or top growth and thus showed no effect of the camptothecin treatment.
Seed leachates of ‘Kentucky 31’ and ‘Rebel’ tall fescue (Festuca arundinacea Schreb.), ‘Citation’ and ‘Manhattan’ perennial ryegrass (Lolium perenne L.), annual ryegrass (Lolium multiflorum Lam.), annual bluegrass (Poa annua L.), and ‘Mystic’ and ‘Victa’ Kentucky bluegrass (Poa pratensis L.) were evaluated for inhibition of lettuce (Lactuca sativa L. ‘Grand Rapids’) germination and seedling growth (a widely used bioassay for allelopathic effects). Different degrees of inhibition of lettuce seedling growth were found in the turfgrass cultivars ‘Rebel’ > ‘Ky31’, ‘Victa’ > ‘Mystic’, ‘Citation’ = ‘Manhattan’, and in annual bluegrass and annual ryegrass. Grass seed leachates were separated into organic and inorganic fractions using XAD-2 polystyrene resin. Organic fractions were inhibitory to lettuce seedling growth. Inorganic fractions were also inhibitory to lettuce seedling growth at high concentrations but were stimulatory at low concentrations. Germination of lettuce was not affected by leachates or their fractions.
An isolate of camptothecin alkaloids was applied to the eyes or sprouts on potatoes (Solanum tuberosum L.) as lanolin suspensions at concentrations of 1.5, 3, 9, and 15 mM, or to the whole tubers as aqueous sprays or dips at various concentrations. Potato sprouting at 15°C was completely inhibited for 4 weeks by all the lanoline suspensions. Inhibition was greater than 95% when a solution of the alkaloids at 5 × 10−1 mM was applied to the tubers as a 3-spray or 3-dip treatment. The camptothecin treatments that inhibited sprouting also reduced weight loss of potato tubers; and even after 4 months at 15°, no symptoms of internal sprouting or other deleterious effects were evident. Electron micrographs of sprouts suggest that camptothecin inhibited sprouting by inducing structural changes in vascular tissues and interfering with cell division in the meristematic portions of the sprouts.