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  • Author or Editor: Michael Dodge x
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Commercial floral products with claimed anti-ethylene effects were evaluated for their efficacy in promoting postharvest longevity of gypsophila (`Perfecta', `Gilboa', and `Golan' baby's breath, Gypsophila paniculata L.). These products were applied according to label directions and compared to a laboratory preparation of silver thiosulfate (STS) prepared as a short pulse treatment and as an overnight treatment; they were also compared to the new anti-ethylene gas, 1-methylcyclopropene (1-MCP). After these pretreatments, the flowers were exposed to ambient air or to 0.7 ppm ethylene gas for 36 hours; other flowers received a simulated shipping treatment. Products containing adequate concentrations of silver consistently extended the display life of gypsophila. Products with low concentrations of silver (<10 ppm) or containing aminoethoxyvinylglycine (AVG) offered no more protection than treatments without anti-ethylene compounds. Overnight treatments with STS were as effective as short pulse treatments. Although 1-MCP pretreatment helped prevent the effects of ethylene on flowers that were open at the time of pretreatment, it provided no protection for buds that opened subsequently. There were no marked differences in ethylene sensitivity among three gypsophila cultivars.

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Commercial formulations of silver thiosulfate (STS) were evaluated for their efficacy in promoting postharvest longevity of gypsophila. Argylene, Chrysal AVB, Chrysal OVB, Oasis Dry Flower Conditioner, Rogard RS, and Silflor were compared to the anionic STS complex and to Physan plus sucrose. Flowers were pulse treated, then placed overnight at 2° C in Physan plus sucrose. Flowers treated with Rogard RS, Chrysal OVB, and Physan were held continuously in the solution. Overnight treatments of STS were compared to short pulses at higher concentrations. To simulate the effect of shipment, treated flowers were packed in boxes, then held either for 48 hours at room temperature (12-18° C) or for 60 hours in a range of ethylene concentrations. Individual stems were then placed in Physan plus sucrose. The number of open flowers, buds, and dead flowers was determined on each stem at various intervals. All products effectively extended the display life of gypsophila except Rogard RS and Chrysal OVB. Although overnight treatments with STS formulations were not as effective as pulse treatments, their convenience could warrant commercial use.

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Salix gracilistyla Miq., japanese pussy willow or rosegold willow, is an ornamental shrub commonly cultivated for its prominent display of catkins in early spring. Verification of stocks of willows in the North American landscape nursery trade revealed that another name—Salix chaenomeloides Kimura—is associated frequently with plants similar to S. gracilistyla. Morphological analyses conducted during this study have shown that the S. chaenomeloides binomial is misapplied often to S. gracilistyla, its cultivars and hybrids. A comparison of the diagnostic characters of S. gracilistyla and S. chaenomeloides is presented to explain the differences between these taxa and to promote the adoption of the correct names. Five cultivars of S. gracilistyla valued for their early spring catkin displays, variegated foliage, and pendulous habits, and two cultivars of a hybrid origin are summarized. Also, two new ornamental cultivars called Salix ‘Winter Glory’ and Salix ‘Rabbit’s Foot’ are described.

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Abstract

The presence of very low concentrations of ethylene had dramatic effects on the opening of cut flowers of rose (Rosa hybrida L.). Depending on cultivar, the rate of opening was unaffected (e.g., ‘Gold Rush’), accelerated (e.g., ‘Sterling Silver’), or inhibited (e.g., ‘Lovely Girl’). The K m for the inhibition of opening of ‘Lovely Girl’ by ethylene was 4 ppb. Flowers of some cultivars (e.g., ‘Royalty’) had an abnormal shape when opened in the presence of ethylene. The effects of exogenous ethylene could be overcome by pretreatment of the flowers with 0.5 μmol silver thiosulfate per stem. No phytotoxicity was observed in flowers treated with 2 μmol per stem. Examination of the kinetics of the ethylene/Ag+ interaction in inhibition of opening of ‘Lovely Girl’ flowers indicated that the Ag+/ethylene interaction was competitive.

Open Access

Three commercially available “anti-ethylene” treatment solutions were tested for their effectiveness in protecting carnations (Dianthus caryophyllus L. `Improved White Sim', `Atlantis', and `Nora'), Beard-Tongue (Penstemon hartwegii x P. cobaea `Firebird'), and Delphinium sp. from external ethylene levels ranging from 0.01 to 1.2 ppm. Flowers were treated according to label directions and then exposed to ethylene for 20 or 24 h at 20 to 23C after a 0-, 24-, or 48-h delay. Only the product containing silver thiosulfate (STS) provided protection against ethylene injury, whereas products containing inhibitors of ethylene synthesis identified as analogs of either aminooxyacetic acid (AOA) or aminoethoxyvinyl glycine (AVG) offered little or no protection. The safe commercial use of products containing STS is discussed.

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