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Margrethe Serek and Arne Skytt Andersen

Miniature rose (Rosa hybrida L. cv. Victory Parade) plants were treated with AOA, BA, or STS before simulated shipment and display in an interior environment. Although AOA-treated plants lasted slightly longer than nontreated plants, their postproduction quality, evaluated as floral longevity, bud drying, and bud abscission, was not as satisfactory as that of STS- or BA-treated plants. In this ethylene-sensitive cultivar, BA treatment was almost as satisfactory as STS treatment. Flowers that opened in the greenhouse before shipping lasted longer than those that opened in the interior environment room. STS and BA treatments increased the longevity of both flower types. However, these treatments did not eliminate the difference between flowers that opened before or after transport simulation. Chemical names used: aminooxyacetic acid (AOA); benzyladenine (BA); silver thiosulfate (STS).

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Margrethe Serek and Michael S. Reid

Spraying flowering plants of Schlumbergera truncata (Haw.) `White Christmas' with aminoethoxyvinylglycine (AVG), an inhibitor of ethylene biosynthesis, did not prevent the rapid loss of flower buds caused by exposure to 1 μl of ethylene/liter. Treatment with the silver thiosulfate anionic complex (STS) strongly inhibited such effects. The rate of bud drop in ethylene-free air (interior environment room) was somewhat reduced by AVG treatment, although total display life of treated plants was not significantly different from that of the controls. STS treatment reduced the rate of bud drop, and increased display life by 20 %.

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Margrethe Serek and Arne Skytt Andersen

Postharvest life of Rosa hybrids L. `Elegance Parade' was increased by 0.2 mm silver thiosulfate and decreased by ethephon at 500 μl·liter-1. In contrast, spraying the plants with various polyamine (PA) concentrations (spermine, spermidine, or putrescine) or the PA-synthesis inhibitor methylglyoxal-guanylhydrazone did not affect postharvest life. Investigation of PA-uptake patterns showed that the compounds were entering the petal tissue.

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Traud Winkelmann, Lara Meyer, and Margrethe Serek

Somatic embryos of cyclamen [Cyclamen persicum Mill.] were produced using a liquid culture system. Two encapsulation techniques, conventional alginate beads and alginate hollow beads, were tested for globular cyclamen somatic embryos with the aim of developing synthetic seeds. Final germination from alginate beads was as high as observed for non encapsulated control embryos (97%), but germination was delayed. In contrast, germination from hollow beads was lower (71%) and occurred later. In hollow beads somatic embryos developed within the capsule, and outgrowth seemed to be more difficult than from alginate. Storage at 4 °C for four weeks resulted in a reduction of viability for controls as well as for encapsulated embryos. Incorporation of medium into the capsules improved the speed of germination for both capsule types. However, somatic embryos were not able to germinate on a medium-free support, even if encapsulated in beads containing medium.

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Margrethe Serek, Rodney B. Jones, and Michael S. Reid

The opening and senescence of gladiolus (Gladiolus sp.) florets was accompanied by climacteric or nonclimacteric patterns of respiration and ethylene production, depending on variety, and whether data were expressed on a fresh-weight or floret basis. A climacteric pattern of ethylene production by the youngest buds on the spike (which never opened) was stimulated by cool storage, and was not affected by holding the spikes in a preservative solution containing sucrose. Ethylene treatment had no effect on senescence of the florets of any of the cultivars tested. Pulse treatment of the spikes with silver thiosulfate (STS) improved floret opening but not the life of individual florets. Sucrose and STS had similar but not synergistic effects on floret opening, suggesting that STS improves flower opening in gladiolus by overcoming the effects of carbohydrate depletion.

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Margrethe Serek, Michael S. Reid, and Edward C. Sisler

Pretreating `Victory Parade' potted miniature roses (Rosa hybrida L.) with photolyzed diazocyclopentadiene (DACP) inhibited the effects of exogenous ethylene (acceleration of leaf and bud drop). In an ethylene-free simulated interior environment, display life of the treated plants was also greater than that of the controls and similar to that of plants pretreated with the anionic silver thiosulfate complex (STS). DACP caused an increase in the binding constant for ethylene in petals and leaves of `Victory Parade' and `Cara Mia' (a cut-flower rose cultivar). Competitive kinetics for the effects of increasing ethylene concentrations on control and DACP-treated plants are consistent with the hypothesis that the effects of DACP are due to irreversible binding to the ethylene-binding site.

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Margrethe Serek, Edward C. Sisler, and Michael S. Reid

A 6-hour fumigation of flowering Begonia ×elatior hybrida Fotsch. `Najada' and `Rosa', B. ×tuberhybrida Voss. `Non-Stop', Kalanchoe blossfeldiana Poelln. `Tropicana', and Rosa hybrida L. `Victory Parade' plants with 1-MCP, (formerly designated as SIS-X), a gaseous nonreversible ethylene binding inhibitor, strongly inhibited exogenous ethylene effects such as bud and flower drop, leaf abscission, and accelerated flower senescence. The inhibitory effects of 1-MCP increased linearly with concentration, and at 20 nl·liter-1 this compound gave equal protection to that afforded by spraying the plants with a 0.5 STS mm solution. Chemical names used: 1-methylcyclopropene (1-MCP), silver thiosulfate (STS).

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Rodney B. Jones, Margrethe Serek, and Michael S. Reid

The vase life of cut sunflowers given a simulated transport period (3 days dry storage at 8C) was significantly enhanced by a l-hour pulse with 0.01% Triton X-100 administered before storage. The Triton pulse increased solution uptake during the l-hour pulse, decreased fresh weight loss during dry storage, and significantly improved water uptake thereafter, resulting in greater leaf turgidity and longer vase life. Leaf stomata] conductance measurements indicated that Triton X-100 maintained stomatal opening at a higher level during the pulse and after storage, but had no effect during dry storage. Chemical name used: octylphenoxypolyethoxyethanol (Triton X-100).

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Margrethe Serek, Edward C. Sisler, Tsipora Tirosh, and Shimon Mayak

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Rodney B. Jones, Margrethe Serek, Chen-Lan Kuo, and Michael S. Reid

Petal opening and senescence of cut Gladiolus, Iris, and Narcissus flowers was significantly inhibited by continuous treatment with 1 mm CHI. Vase life was doubled in individual flowers treated when half-open, and a similar effect was detected after pulsing cut gladiolus spikes with 1 mm CHI for 24 hours. Petal wilting was markedly inhibited in flowers treated with CHI and was confined to the outer 2 to 3 mm of petal margins as opposed to the entire petal in untreated flowers. These effects were not seen, however, in CHI-treated cut tulip flowers, where vase life was significantly reduced. CHI markedly inhibited protein synthesis in Gladiolus `New Rose' florets (a decrease of >60%). Treatment with a potent biocide, DICA, did not increase vase life; therefore, CHI was not prolonging flower longevity by preventing microbial growth in the vase solution. The results indicate that de novo protein synthesis is required for bulb flower development and opening and petal wilting and senescence. Chemical names used: cycloheximide (CHI), sodium dichloroisocyanuric acid (DICA).