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Brigitte D. Crawford, John M. Dole, and Ben A. Bergmann

been harvested) from the same stock plants, or stock plant age. This study had two main objectives. The first was to determine if cutting quality and rooting success of ‘Stained Glass’ coleus are influenced by season, cutting week within a propagation

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Michael R. Evans

proposed as an aggregate to adjust the physical properties of peat-based substrates. Growstones were produced from finely ground waste glass. The ground glass powder was combined with calcium carbonate and heated in a kiln. The heat resulted in the

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L.E. Towill

Cryopreservation using vitrification has been reported for several plant species. Shoot tips and vitrification solution were placed in semen straws and immersed in liquid nitrogen (LN). Cracking of the external glass occurred, but may be avoided by annealing slightly below the glass transition temperature before immersion. A varying percentage still cracked with some vitrification solutions. Rapid warming also can cause cracking. There is concern that cracking may reduce viability. Shoot tips from Mentha species were used to examine this problem. Glass cracking during either cooling or warming did not produce visible damage to shoot tips. Viability of shoot tips from tubes that cracked during cooling was not different from those that did not crack; however, shoot formation was slightly reduced. Cracking upon warming did not reduce viability nor shoot formation. Very slow warming reduced viability, but warming in either water or air (room temperature) gave higher levels of survival.

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Alejandro Martínez Palacios, Raúl Cárdenas Navarro, Diana Beatriz Hernández Ortega, and Víctor Chávez Avila

Turbinicarpus valdezianus (Möeller) Glass & Foster (Cactaceae), endemic cactus from a very specific and narrow habitat in Northern México, is highly prized by collectors due to its peculiar morphology and attractive flowers ( García-Osuna et al

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Marihelen Kamp-Glass

Oral Session 29—Teaching Methods Moderator: Marihelen Kamp-Glass 21 July 2005, 8:00–9:45 a.m. Room 107

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Gene A. Giacomelli and William J. Roberts

The diversity of coverings for the greenhouse and other plant production structures has increased dramatically during the past 4 decades. This has resulted from the availability of new types of covering materials and enhancements of previously existing materials, as well as the demands for technological improvements within the expanding controlled environment agricultural industry. The types of coverings currently available are dominated by plastics. These range from traditional glass to the recent advent of polymer plastics, such as thin films or multilayer rigid thermoset plastic panels. Available enhancements such as ultraviolet radiation (UV) degradation inhibitors, infrared radiation (IR) absorbency, and anti-condensation drip surfaces, as well as their physical and spectral properties are discussed. The selection of specific covering alternatives has implications for the greenhouse superstructure and its enclosed crop production system.

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D. Powell, R. Kelley, G. Yang, and M. Kamp-Glass

Alfalfa (Medicago sativa L.), one of the most important forage legumes in the United States, has been recognized as an aluminum-sensitive species (Kemp-Glass et al., 1993). Hematoxylin staining has been used to evaluate differences in root growth and stain uptake between sensitive and resistant individuals in wheat (Ruiz-Torres et al., 1992). Attention in this study is focused on the hematoxylin staining pattern because the procedure is simple and rapid. Ten alfalfa cultivars were used: `Apollo', `ARC', `Foundation Vemal', `Shenandoah', `Spreador 2', `WL 311', `Saranac', `Saranac AR', `Cimarron', and `Cimarron VR'. Twenty seeds of each were stained in a solution of hematoxylin for 2 days. After staining, the seedlings were transferred to a potting medium for 14 days. After 14 days, plantlets were transferred to Porters soil (pH 4.5, 80% aluminum saturation) and grown in the greenhouse for 60 days. After 60 days, fresh and dry root and shoot weights were taken. Root length densities were determined and these parameters were compared to the tolerance level predicted by hematoxylin stain. Results of stain correlate with biomass at highly significant levels and will be of great use in the development of an acid/aluminum-tolerant alfalfa.

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Roberto Nuñez-Elisea and Jonathan H. Crane

Carambola (Averrhoa carambola L.) is native to the humid tropics of southeastern Asia, where it bears fruit year-round. In south Florida, winter conditions (strong winds and night temperatures below 15 °C) repress growth and flowering of the main commercial cultivar, Arkin, and fruit is produced from July to February. Off-season fruit would reach premium prices. We have previously demonstrated that selective pruning stimulates flowering of carambola at any time of the year. However, flowers produced during cool, windy weather have consistently failed to set fruit. This study was conducted in 1994–1995 to determine whether protected cultivation would help obtain off-season fruit. Four-year-old `Arkin' trees growing in 80-L containers were placed in a glasshouse or outdoors and pruned in November or December to force flowering during December–January. Glasshouse night temperatures during the winter were above 20 °C. All trees flowered in response to pruning. Outdoor trees produced less than one fruit per tree in late March to late April. Glasshouse trees produced 2.3 to 6.1 fruit per tree, 2 to 3 weeks earlier than trees outdoors. In the glasshouse, more than 98% of fruit were seedless, whereas all fruit produced outdoors were seeded. Production of seedless fruit indoors was achieved in the absence of insect pollinators, and yields were low compared to those of outdoor trees during the summer (at least 25 fruit per tree). We speculate that, under protected cultivation, the use of synthetic bioregulators during anthesis and insect pollinators may help increase production of off-season seedless and seeded fruit, respectively.

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Marihelen Glass

Most people do not even know the definition of immediacy. It is the perception of physical or psychological closeness: verbal and nonverbal. The practice of immediacy in the class room can help student behavior in the class room. Examples of Teacher Immediacy in the class room areas follows. 1) How the teacher's appearance can affect the student's learning. 2) What the teacher's gestures and movements mean. 3) How facial behavior can be positive or a negative to the student. 4) How eye behavior can affect the student's learning. 5) How the teacher's vocal behavior affects the attentiveness. 6) How the environment in the classroom affects the student's ability to concentrate.

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Marihelen Kemp-Glass

A major problem in the pot production of Zantedeschia (Calla Lillies) is the bacterial soft rot Erwinia carotovora. Sometimes if the corn is infected there may be no symptoms until the plant falls over. This disease can destroy an entire crop very quickly. Z. albomoculata, Z. Elliottiana', Z. Solfatare; and Z rehmannii were soaked for 5 minutes and 10 minute in 50 ppm and 100 ppm respectively in Agrox Strep a combination bactericide and fungicide. The 50 ppm for 5 minutes gave sufficient control of soft rot provided the plants were not overwatered. However, if overwatered the incidense of soft rot did reoccur. This was controlled by watering the plants every 10 days with 50 ppm of Agrox Strep.