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Delivery of modern extension programs involves considerable expenses that are becoming scarce from traditional sources. Successful extension educational programs will need to find additional revenue sources to fund educational materials, speaker costs, conferences, and other needs. It is important to become as financially efficient as possible and sometimes this means consolidating some programs and eliminating others. Charging fees to attendees is one means of covering costs of delivering programs. The University of Florida is partnering with the agriculture industry and trade journal publishers to provide resources and publishing for educational programs and materials.
Abstract
Peach floral cup extracts were assayed for an inhibiting substance thought to be abscisic acid (ABA) at weekly intervals from November 11, 1969 to February 17, 1970. Inhibitor levels fluctuated during rest, but were relatively high at the termination of the rest period. Inhibitor levels then decreased after the chilling requirement was satisfied. Floral cup growth during the rest period was an exponential function.
Abstract
Cyanide-resistant respiration in carnation (Dianthus caryophyllus L.) petal tissue increased daily until 3 days after flowers were harvested. Mitochondria from petals exhibited only cyanide-resistant respiration when malate and pyruvate were provided as substrate. Although intact petals from freshly harvested flowers exhibited little cyanide-resistant respiration, mitochondria isolated from them were highly cyanide-resistant in their respiration if malate and pyruvate were provided as substrate. Pyruvate, in mitochondria, was capable of releasing mitochondria inhibited by cyanide in the presence of malate. Pentose-phosphate pathway activity was significant throughout the postharvest period, but was maximum 5 days after flowers were harvested. The gas exchange quotient (GEQ) was 1 for the first 3 days after harvest, declining on days 4 and 5 and dramatically increasing on day 6 as a result of a climacteric increase in CO2 evolution accompanying flower wilting.
Many plants can produce bioactive chemicals with medicinal or health benefits, which has stimulated a whole new research effort aimed at extracting & improving natural phytochemicals. Begonia is a rich source of biologically-active phytochemicals and an excellent donor for natural anthocyanin pigments. High levels of triterpene compounds and a host of potentially-useful flavonoids have been isolated from Begonia sp., which may account for its frequent use as a medicinal plant remedy in a diverse array of cultures worldwide. Deliberate shifting of the physical and chemical microenvironments can have a significant effect on anthocyanins and precursors produced in vitro. This realization offers the potential to thoroughly screen and study valuable phytochemicals from Begonia. Begonia genotypes from 3 species were screened to identify callus induction techniques. Contamination inherent in the vascular system of one genotype, along with spontaneous organogenesis, were found to be recurrent problems. These were partially alleviated by light and growth regulator treatments. Studies comparing callus and in vitro vegetative tissues as resources for phytochemical extraction are scheduled.
Four interspecific grape hybrids (Vitis spp.) developed in Arkansas were evaluated for primary bud hardiness by differential thermal analysis. Buds from two locations were analyzed over 2 years for acclimation, midwinter hardiness, and deacclimation. In addition, effects of two training systems on cold hardiness of buds were evaluated in one location. The buds of the two genotypes with the greatest component of V. vinifera in their ancestry acclimated more slowly than did the other genotypes. Ultimate midwinter bud hardiness was greater in the genotypes possessing less V. vinifera than other parentage. No effect on cold hardiness due to training system was noted. No natural winter freeze damage was observed on any of the genotypes in the period of observation.
Seeds of Aquilegia chrysantha Gray were germinated under a variety of temperature regimes. Germination was nearly 90% under a day/night cycle of 25/20C, but was reduced to ≤ 40% under constant 25C or a 25/10C day/night cycle. With days between 25 and 29C (night = 20C), germination percentage dropped gradually to ≈ 60% with increasing temperature. With days >29C, germination declined dramatically such that no germination occurred at 31C. Neither kinetin (4.6 to 46 μm) nor ethephon (6.9 to 207 μm) was able to reverse the inhibitory effects of 33C days. Our results indicate that germination of A. chrysantha seed is sensitive to temperature and that germination ≈ 75% can be obtained under a 25 to 27C day/20C night regime. Chemical names used: 2-chloroethylphosphonic acid (ethephon); 6-furfurylaminopurine (kinetin).
Seeds of Aquilegia chrysantha Gray were germinated under a variety of temperature regimes. Germination was nearly 90% under a day/night temperature regime of 25/20C but was reduced to 40% or less under constant 25C or a 25/10C day/night temperature regime. At day temperatures between 25 and 29C (night temperature = 20C), germination percentage dropped gradually to about 60% with increasing temperature. Above a day temperature of 29C, germination declined dramatically such that no germination occurred at 31C. Neither kinetin (1-10 mg/liter) nor ethephon (1-30 mg/liter) were able to reverse the inhibitory effects of a 33C day temperature. Our results indicate that seed germination of A. chrysantha is quite sensitive to temperature and that germination percentages of 75% or greater can be obtained under a 25-27C day/20C night temperature regime.
Nodal explants were taken from both vegetative and flowering shoots of `German Red' carnation and placed on MS medium supplemented with 2.0 mg/L benzylaminopurine (BAP) and 0.5 mg/L naphthaleneacetic acid. The explants taken from flowering shoots invariably produced flower buds in vitro and were of no value for micropropagation. With the vegetative explants, microshoots were observed after about 15 days. These were subcultured and the effect of cytokinins (kinetin, BAP, thidiazuron [TDZ]) on subsequent shoot production was evaluated. The cytokinins increased the number of shoots formed with TDZ and kinetin being the most and least effective, respectively. Shoots produced in vitro were rooted with 100% success in vitro or ex vitro. About 98% of the plants rooted in vitro or ex vitro survived transfer to the greenhouse and were successfully transplanted outdoors. In summary, starting from explants, well-branched flowering plants can be obtained in as little as 5-6 months. These results suggest that in vitro mass propagation of `German Red' carnation is feasible.