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  • Author or Editor: Mark P. Bridgen x
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Seven resin-coated fertilizers (RCF) (Osmocote 19–6–12, 18–6–12, 14–14–14, 13–13–13, and 19–6–12, and Polyon 19–6–12, 17–17–17, and 13.5–13.5–13.5) were applied to marketable potted Alstroemeria hybrid FL101 plants to determine their effects on postproduction flowering and growth. The nonfertilized control produced the greatest number of floral stems, total florets, and mean number of florets per stem, but these plants were extremely chlorotic and spindly, and had the lowest fresh weight and number of vegetative stems. In a subsequent experiment, plants were fertilized with low, medium, and high concentrations of either Osmocote 19–6–12 or Sierra HighN 24–4–8. Nonfertilized controls were again chlorotic and spindly, but produced as many florets as fertilized plants. Plants fertilized with Osmocote 19–6–12 had greater fresh weight and more vegetative stems, but fewer total florets than those fertilized with Sierra HighN 24–4–8. We concluded that potted Alstroemeria do not need fertilizer for continued flowering, and fertilization favors production of vegetative stems relative to flowering stems. However, application of RCF to marketable plants prevents chlorosis, increases fresh weight, and, if low to moderate rates of formulations with N–P ratios of at least 6:1 are applied, does not inhibit flowering.

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A laboratory exercise on direct and indirect organogenesis from leaf explants is presented for students of plant tissue culture or plant propagation. Torenia fournieri, the wishbone flower, is used for this laboratory exercise because the in vitro production of adventitious shoots from Torenia is easy to control, seeds are easy to obtain, and plants are easy to grow. Direct shoot organogenesis results from leaf explants without an intervening callus phase, and indirect shoot organogenesis is possible after 4 to 6 weeks of callus production from leaf explants. The basal medium for all forms of organogenesis contains Murashige and Skoog (MS) salts and vitamins, 30 g sucrose/liter, and 7 g agar/liter at pH 5.7. To obtain direct shoot organogenesis, leaf explants should be placed on the MS basal medium with 1.1 μM (0.25 mg·liter-1) 6-benzylaminopurine (BAP) and 0.25 μM (0.05 mg·liter-1) indole-3-butyric acid (IBA). If leaf explants are placed on MS medium with 2.3 μM (0.5 mg·liter-1) 2,4-dichlorophenoxyacetic acid (2,4-D), callus formation will occur. Callus can be subcultured onto a MS medium with 8.88 μM BAP (2.0 mg·liter-1) plus 2.5 μM IBA (0.5 mg·liter-1) for indirect shoot organogenesis to occur.

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Endogenous ethylene levels and ethylene production rates increased in excised leaf petioles of plants that were previously bent due to sleeving of potted Euphorbia pulcherrima Wild. cvs. Annette Hegg Dark Red and Improved Rochford. Intact leaf blades were required during the sleeving period for petiole epinasty to occur. Storage of unsleeved plants for 66 or 70 hours under 4% O2 or 150 mm Hg enhanced epinasty and endogenous ethylene levels. Sleeved plants under these same environmental conditions exhibited an equal proportion of epinastic petioles as sleeved plants under normal conditions but the endogenous ethylene level upon removal from storage was highest in the 150 mm Hg treatment when compared to all other treatments.

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