The postharvest life of cut Eustoma grandiflorum flowers is limited by poor bud opening and bent neck in open flowers. Vase solutions containing up to 6% sucrose or glucose improved the quality and vase life of the flowers. The additional carbohydrate improved petal color, increased bud opening, strengthened pedicels, and extended overall inflorescence longevity by up to 8 days. The principal sugar in the petals of open flowers was glucose, with lower concentrations of sucrose and fructose. Presence of sugar in the vase solution greatly increased the concentration of sugars in the perianth of buds and open flowers. Eustoma flowers are affected by exposure to ethylene and pre-treatment with 1-MCP or STS delays final senescence of flowers that have been held in solutions containing sugar. IntroductionLisianthus, or the Texas gentian, Eustoma grandiflorum (Raff.) Shinn., native to the prairie states of North America, is now an important commercial cut flower (Halevy and Kofranek, 1984). Hybrids developed in Japan provide a wide range of colors, color patterns, and both single and double forms. Lisianthus has become very popular as a cut flower, because of the range of colors available, and the fact that each inflorescence comprises a long, straight stem bearing as many as 10 individual flowers. In addition, the plants (which may be annual or biennial depending on the growing environment) bear as many as 10 inflorescences over the production season (Tjia and Sheehan, 1986).Although there have b een many studies of the environmental conditions required for lisianthus production, there has been little examination of the postharvest characteristics of the flowers. Lisianthus is usually harvested commercially when the first one or two flowers on the stem have opened. A good quality inflorescence will usually have ten or more buds and flowers. If the flowers are placed in water, few if any of these buds open, and the longevity of the inflorescence is therefore determined by the life of the open flowers. Frequently, too, the life of the flowers is shortened by premature wilting and bending of the pedicels of the open flowers.In other bud-type cut flowers, it has long been known that bud opening (and consequently display life of the inflorescence) can b e enhanced by the addition of carbohydrate. This can be achieved either by using a postharvest pulse with a high concentration of sugar, as in gladiolus (Mayak et al., 1973) (Han, 1992). Halevy and Kofranek (1984) recommended a pulse with 5-10% sucrose for 24 hours to improve postharvest life of Lisianthus flowers, and Farina et al. compared a number of such pulses. They fo und that pulsing with Chrysal or TOG (with 4% sugar) was ineffective, but that TOG with 10% sugar or 8-HQS with 10% sugar were both effective pulses. Song et al. (1994) tested the effects of STS pre-treatment, and found a modest improvement in bud opening, but also showed that a standard holding solution containing biocides and 2% sugar increased flower life three-fold. Ichimura and Korenaga (199...

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A study was conducted to determine the potential for using ground automobile tires as a container medium amendment. Rooted cuttings of chrysanthemum [Dendranthema × grandiflorum (Ramat.) Kitamura] were planted in 1.56-liter pots containing 1 sand:2 sawdust (v/v) or media in which coarsely or finely ground particles of rubber substituted for 33%, 67%, or 100% of the sawdust. Amendment with the coarse material decreased total porosity and container capacity and increased air-filled porosity and bulk density relative to the sawdust control. Amending the medium with the fine material did not appreciably alter total porosity, container capacity, or bulk density, but did increase air-filled porosity. Plant height, fresh weight, dry weight, and number of open flowers were reduced significantly in rubber-amended media compared to sawdust controls. Rubber amendment reduced shoot tissue concentrations of N, P, K, Ca, Mg, and Cu, but increased Zn as much as 74-fold over control values. There was no accumulation of other heavy metals (Cd, Cr, Ni, Pb) or Na in the tissue due to rubber amendment. This study demonstrates that ground tires might be used as a component of container media in the production of greenhouse chrysanthemums. However, growth reductions and the potential for Zn toxicity may limit the usefulness of ground tires as a substitute for conventional organic amendments.

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