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Bring together a university landscape horticulture professor who believes in school gardens, a landscape design class, a landscape construction class, enthusiastic elementary school teachers and a willing principal, and you can create wonderful teaching gardens. The interactions among university students, elementary teachers, and students were a true learning experience for everyone. University students were involved in a true problem-solving project, being forced to look at problems and solutions through the eyes of elementary school children. Their expertise was valued as they were asked to explain horticulture to first and second graders. For some, this was the first time they really understood some of the concepts. Teachers and students were active participants throughout the process. Sharing thoughts and ideas was dynamic throughout the design and construction. Ways to initiate and maintain university–school partnerships will be presented.
Good written communication skills are essential for the success of our graduates. To promote good writing, students in Ornamental Plant Identification classes have been required to write mini-essays, one-page responses to real-world scenarios. Student's responses have been good and their writing has been very acceptable. The mini-essays were, however, just assignments to complete. In an attempt to get students truly involved and passionate about their writing, assignments were designed to illicit creative, fun responses. Students were asked to explain concepts to fourth graders. This brought responses that ranged from exercises where kids were to stick out their tongues to imitate humming birds, to a short play demonstrating the importance of plant nomenclature. Another assignment asked students to complete a story about the famous detective, Hortus paradoxa. Student responses were incredibly creative, and some of the best writing I have ever seen. In addition, students had fun. It seems clear that, if students know that it is OK to be creative, they will greatly exceed your expectations. Just be prepared to have lots of fun while learning. Samples of the assignments, responses, and what is next will be presented.
Water loss of Nerium oleander growing in two soil types was determined from mid-June through mid-October. Plants (1 year old, 3.8 liter) were obtained from a local nursery and transplanted in May into 18.9-liter Iysimeter pots containing either clay loam or bluepoint sand. Controls were lysimeter pots containing each soil type but without plants. Irrigation was applied at two rates, approximately field (pot) capacity and 50% of that amount. Irrigation frequency was determined by visual inspection of the plants and was held constant for both irrigation rates in a given soil type. Frequency ranged from 2 to 3 days for the sand and 2 to 5 days for the clay loam. Water loss was determined every 24 h. Plant water loss was higher at the higher irrigation rate. Decreasing irrigation rate by 50% resulted in a 20% to 40% reduction in plant water use in clay loam and a 15% to 30% reduction in sand without affecting plant quality. Plant water loss in the sandy soil was ≈50% greater than in clay loam 48 h after irrigation. Implications of these findings in developing an optimum irrigation model for landscape plants will be considered.
Abstract
Ethylene evolution induced by nonionic (Triton X-100, Triton X-405, Tween 20, Ortho X-77 and Regulaid), anionic (Aerosol OT and Dupanol ME), and cationic (Arquad C-50 and Arquad 2C-75) surfactants was characterized using cowpea [Vigna unguiculata (L.) Walp. supsb. unguiculata ‘Dixielee’] seedlings. Representative surfactants of each ionogenic class induced ethylene evolution. Time course studies revealed an increased rate of ethylene evolution during the first 6 to 12 hr after treatment, followed by a slow decrease for the next 12 to 36 hr, and a return to control levels within 48 hr. Ethylene production induced by Triton X-100 increased with increasing concentration, while Tween 20 did not induce ethylene at concentrations up to 1.0%. Surfactants that promoted ethylene evolution also generally induced visible phytotoxicity. Phytotoxicity symptoms increased with increasing time after treatment. Surfactant-induced ethylene production and phytotoxicity were observed with corn (Zea mays L. ‘B73 × MO17’), wheat (Triticum aestivum L. ‘Hillsdale’), soybean (Glycine max Merr. ‘McCall’), apple (Malus domestica Borkh. ‘Golden Delicious’), and sour cherry (Prunus cerasus L. ‘Montmorency’). Tween 20, nonactive on cowpea, induced ethylene and phytotoxicity when applied to the abaxial surface of sour cherry leaves. Chemical names used: octyl-phenoxypoly(ethoxy)ethanol (Triton X-100 and X-405), polyoxyethylene sorbitan monolaurate (Tween 20), alkylaryl polyoxyethylene glycols/free fatty acids/isopropanol (Ortho X-77), polyoxyethylenepolypropoxypropanol alkyl 2-ethoxyethanol/dihydroxy-propane (Regulaid), diocytl sodium sulfosuccinate (Aerosol OT), sodium lauryl sulfate (Dupanol ME), monococo trimethyl ammonium chloride (Arquad C-50), dicoco dimethyl ammonium chloride (Arquad 2C-75).
Abstract
Surfactant toxicity was examined following application of octylphenol and linear alcohol surfactants to the adaxial surface of 10-day-old cowpea [Vigna unguiculata (L.) Walp. subsp. unguiculata ‘Dixielee’] leaves. Leaf damage first appeared as isolated discolored areas at the periphery of the droplet area, developed toward the center, and, when most severe, the entire droplet area was necrotic. Epidermal cells beneath the droplet area became discolored, lost structural integrity and collapsed. Similar changes were observed in the palisade layer and spongy parenchyma. In addition, walls of damaged cells were preferentially stained with Safranin O. For a given surfactant dose, phytotoxicity increased with increasing concentration, droplet volume, and temperature and decreased with increasing humidity. In general, phytotoxicity was inversely related to the length of the ethoxy (EO) chain for both the octylphenol (Triton X) and C12-15 linear alcohol (Neodol 25) surfactant series. Tissue did not recover after injury. Chemical names used: octylphenoxypoly(ethoxy)ethanol (Triton X-100), linear alcohol ethoxylate (Neodol 25-9).
Writing is an integral part of a career in horticulture. Most successful horticulturists write not only in communicating with peers, but also in keeping extensive journals or records of their activities. These tasks use different writing skills. Writing in horticulture classes should reflect, encourage, and provide practice in both types of writing. Assignments should reflect the students' career choices and provide writing practice in an appropriate genre.
Previous work has shown that container grown landscape plants use, and likely need, much less water than is typically applied. Therefore, studies were conducted to quantify the relationships between water loss and water stress responses using several drought tolerant (Cassia corymbosa, Leucophyllum frutescens, Salvia greggii) and traditional landscape plants (Euonymus japonicus, Pyracantha coccinea). Water stress was induced by withholding water and water loss measured gravimetrically. The shape of the water loss curve was similar for all species being, Y = a + bx + cx2 (r2 > 0.95). The rate of ethylene production began to increase 24 hr after irrigation, reaching a maximum 36-48 hr after irrigation and then decreasing. Maximum ethylene production occured at 35-47% water loss irrespective of species or rate of water loss. Stress symptoms (wilting leaf discoloration and abscission) followed a similar pattern. The potential for monitoring gravimetric water loss to schedule container irrigation will be discussed.
Previous work has shown that container grown landscape plants use, and likely need, much less water than is typically applied. Therefore, studies were conducted to quantify the relationships between water loss and water stress responses using several drought tolerant (Cassia corymbosa, Leucophyllum frutescens, Salvia greggii) and traditional landscape plants (Euonymus japonicus, Pyracantha coccinea). Water stress was induced by withholding water and water loss measured gravimetrically. The shape of the water loss curve was similar for all species being, Y = a + bx + cx2 (r2 > 0.95). The rate of ethylene production began to increase 24 hr after irrigation, reaching a maximum 36-48 hr after irrigation and then decreasing. Maximum ethylene production occured at 35-47% water loss irrespective of species or rate of water loss. Stress symptoms (wilting leaf discoloration and abscission) followed a similar pattern. The potential for monitoring gravimetric water loss to schedule container irrigation will be discussed.
Physical characteristics [initial water content, surface area, surface area: volume (SA: V) ratio, cuticle weight, epicuticular wax content, and surface morphology] were examined to determine relationships between physical properties and water-loss `rate in pepper fruits. `Keystone', `NuMex R Naky', and `Santa Fe Grande' peppers, differing in physical characteristics, were stored at 8, 14, or 20C. Water-loss rate increased linearly with storage time at each temperature and was different for each cultivar. Water-loss rate was positively correlated with initial water content at 14 and 20C, SA: V ratio at all temperatures, and cuticle thickness at 14 and 20C. Water-loss rate was negatively correlated with surface area and epicuticular wax content at all temperatures. Stomata were absent on the fruit surface, and epicuticular wax was amorphous for each cultivar.
Nine pepper cultivars (Capsicum annuum L.) representing five pepper types were studied to determine water-loss rates, flaccidity, color, and disease development when stored at 8,14, or 20C for 14 days. Water-loss rate was markedly higher at 14C than at 8C, and was somewhat lower at 20C than at 14C. There were significant differences in water-loss rates between pepper cultivar with `NuMex R Naky', `NuMex Conquistador', and `New Mexico 6-4' (New Mexican-type peppers) having the highest water-loss rates. Flaccidity followed a pattern similar to water loss at each storage temperature, suggesting a direct relationship. Color development was cultivar- and package-dependent, and ratings increased with temperature. Placing pepper fruit in perforated polyethylene packages reduced water-loss rates 20 times or more, so that water loss no longer limited postharvest storage. Packaging also eliminated flaccidity and reduced color development across cultivars at 14 and 20C. Packaged fruit, however, developed diseases that limited postharvest longevity.