J. George Buta

Maintaining quality of fresh-cut kiwifruit with volatile compounds

Kiwifruit (Actinidia deliciosa ) were cut into 5 mm slices and placed in polystyrene trays. Various volatile compounds were introduced inside the trays before the lids were covered. The development of decay and the shelf life of the slices were evaluated during storage at 10 8C. Kiwifruit slices treated with 2.24, 11.2, or 22.4 m ll � 1 methyl jasmonate maintained good quality after 3 weeks at 10 8C compared to the control slices. Comparable results were obtained with absolute ethyl alcohol (300 m ll � 1 ) or isopropyl alcohol (300 m ll � 1 ). However, 1-propanol was less effective and methyl alcohol was not effective in maintaining the quality of kiwifruit slices. Methods of application affected the efficacy of the volatile compounds. In general, suspension of the source of volatile compounds within the trays yielded better results compared to volatilization of the volatile compounds from beakers placed inside the trays. In addition to having less decay, kiwifruit slices treated with methyl jasmonate also maintained higher levels of sugars and organic acids compared to the untreated slices. Measurement of oxygen and carbon dioxide concentrations in the trays indicated that oxygen never dropped below 19.5% and carbon dioxide remained at approximately 0.8% in all treatments during the 3 weeks at 10 8C. No differences in respiration rates between methyl jasmonate treatment and control were detected. Ethylene production increased during the first 7 days and then decreased gradually. However, no differences in ethylene production between methyl jasmonate treatment and control were found. Published by Elsevier Science B.V.

Catechins as germination and growth inhibitors in Lespedeza seeds

Abstract The germination and growth inhibiting compounds found in Lespedeza bicolor, L. cuneata and L. stipulacea seeds have been shown to be catechin and epicatechin. Differences in time of germination and amount of early seedling growth (L. stip. >L. cun. = L. bic.) were inversely related to the quantities of these polyphenols found in the seeds.

The role of abscisic acid and plant growth regulators in tissue culture-induced rejuvenation of strawberry ex vitro

Plant growth regulators applied in vitro affected strawberry plant performance ex vitro for a period of up to 4 months. Benzyl-adenine and gibberellin enhanced juvenile characteristics; in general, more runners and monofoliolate leaves were produced, net photosynthesis was reduced, leaf diffusive resistance was increased and, on occasion, flowering was delayed. In contrast, abscisic acid and a gibberellin biosynthesis inhibitor, paclobutrazol, resulted in a more adult phenotype; specifically, flowering was earlier, net photosynthesis and leaf diffusive resistance rates were equal to those of adult plants, and fewer leaves were monofoliolate. Tissue culture-produced plants reacquire the adult phenotype earlier than seedlings mature. Abscisic acid application to seedlings also resulted in earlier and increased flowering.Endogenous abscisic acid concentrations were greater in adult plants and less in tissue culture and seedling plants at 3 and 7 weeks ex vitro, after germination or after adult runner propagation. No flowering occurred at 3 weeks in any propagation type and only runner-produced plants flowered at 7 weeks. At 15 weeks, no statistical difference in abscisic acid concentrations existed among propagation treatments and all propagation types flowered. The endogenous concentrations of abscisic acid in plants propagated by all three methods were much higher at three weeks compared to concentrations at 7 or 15 weeks.

Fourier transform infrared spectra of zucchini squash stored at chilling or non-chilling temperatures

Abstract Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products or vendors that might be suitable. Fourier transform infrared spectroscopy (FTIR) was used to investigate spectral changes in the epidermis of zucchini squash resulting from low temperature storage-chilling (5°C) or non-chilling (15°C). Increased levels of fluid (water) were found in the tissue after 2 days of 5°C storage. This increase was reversed to harvest levels when chilled squash were warmed to room temperature for 1 day. After 3 days at 5°C and 1 day at room temperature, a further increase in fluid levels was found in the epidermis. Squash chilled for 3 days were apparently beyond recovery as indicated by spectral changes, although visual symptoms of chilling injury were not apparent until another 3 days of exposure to 5°C. Spectra of epidermis tissues from squash stored at 15°C indicated a pattern of increased non-reversible fluid accumulation when storage was prolonged. These results suggest that FTIR spectroscopy may be a rapid way to detect changes in chilled tissues before the eventual appearance of visible symptoms.