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Min Hyeong Kwon, Jongyun Kim, Changwan Seo, Chiwon W. Lee, Eu Jean Jang, and Woo-Kyun Lee

This study examines the current status, implementation, and foci of children’s education programs as a subset of general audience-targeted public education programs offered by public children’s gardens in the United States. Children were a major target audience of the examined public gardens, followed by adults, families, and youth. Public children’s gardens tended to offer more programs overall compared with public gardens without children’s gardens. In addition, there was a greater diversity of children’s education programs offered (classified into 10 topics and 11 activities) in public children’s gardens. The most frequently offered topics were plants (39.1%), animals (22.0%), and art (11.3%). Observation was the most frequently offered activity (17.1%), followed by visual art (14.4%). However, the proportions of offered programs significantly differed across individual public children’s gardens. The subjects (i.e., topics and activities) offered by children’s education programs were more often directed toward younger children. Education coordinators and horticulture directors were asked about desired improvements to children’s education programs. A large number of respondents (50) indicated a need to develop programs with greater topical variety, revealing a desire to diversify programs. In conclusion, the results of this study indicate that it is important to diversify the natural environmental experiences of education programs for children through developing children’s gardens and age-specific education at public children’s gardens in the United States.

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Keun Ho Cho, Chiwon W. Lee, Larry J. Cihacek, Robert W. Stack, and Hoon Kang

The influence of calcium (Ca++) nutrition on the growth and root tissue electrolyte leakage (EL) of carrot (Daucus carota) was investigated using a hydroponic culture system. Seedlings of `Navajo' carrot were grown for 10 weeks with roots submersed in hydroponic nutrient solutions containing 0, 0.1, 1, 2, 4, or 8 meq/L Ca++. The nutrient solution was replenished weekly with its pH maintained at 5.8 for the entire experimental period. The tap root lengths increased as solution Ca++ concentration increased. The diameter and fresh and dry weights of the tap roots increased as Ca++ concentration increased up to 4 meq/L, and then decreased at 8 meq/L Ca++. The root and petiole concentrations of sugar, potassium, and nitrate were unaffected by changes in nutrient solution Ca++ levels. The tissue EL, when tested for the stored roots, decreased as solution Ca++ concentration increased (r = 0.602). Results of this experiment suggest that calcium nutrition is essential for maintaining cell wall integrity in hydroponically grown carrot roots.

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Chiwon W. Lee, Keun Ho Cho, Larry J. Cihacek, and Robert W. Stack

The influence of calcium nitrate fertilization on the storage characteristics of carrot (Daucus carota) roots was investigated. Plants of `Navajo' carrots grown under irrigation were sprayed with a 2% solution of Ca(NO3)2 4H2O at a rate of 50 kg/ha Ca 10 days before harvest. Quality of carrot roots stored at 5 °C was evaluated monthly for sweetness, tissue electrolyte leakage, disease development and visual characteristics. For disease development, the crown portion of the carrot roots was inoculated with an ascospore solution (2 × 109 spores/mL) of white mold (Sclerotinia sclerotiorum) before storage. When determined after 1 month of storage, percent tissue electrolyte leakage in the Ca-treated carrots decreased 52% as compared to that obtained from the control. Sugar contents of the cortex and xylem tissues were not affected by calcium nitrate fertilization. Changes in other quality parameters of carrot roots for an extended storage period, including white mold development, will be presented. Initial findings of this research suggest that foliar calcium feeding at the final stage of plant growth may enhance the quality of carrot roots during storage.

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Hoon Kang, Abbas Lafta, Chiwon W. Lee, Murray E. Duysen, and Larry Cihacek

The influence of potassium (K) nutrition on the growth and sugar contents of carrot (Daucus carota L.) cv. Navajo was investigated in a greenhouse study. Seeds were germinated in 15-cm plastic pots (volume1.5 L) containing a peatlite mix (2 parts peat:1 part vermiculite:1 part perlite, v/v). Starting at 6 true-leaf stage (5 weeks from germination), plants were watered with nutrient solutions containing 0, 1, 2, 4, or 8 meq K/L for 10 weeks. While plants receiving no potassium had the lowest biomass yield, there was little or no difference in shoot or root biomass yields between different K concentrations. Root glucose and sucrose contents were the highest when plants grown with 8 meq K/L and 4 meq K/L, respectively, from the nutrient solution. The influence of nutrient solution K concentration on tissue content of K and other macronutrient elements was also determined.

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Lijuan Wang, Nian-Oine Shi, Murray E. Duysen, and Chiwon W. Lee

Cleistogamy in Salpiglossis sinuatu L. involves a sequence of events, including arrested corolla development, precocious pollen germination inside anther, pollen tube penetration of the pistil, and eventual self fertilization, that takes place. within a tightly closed flower bud. A single dominant gene (C) controls cleistogamy in this plant. During early blooming period, cleistogamous (CC, Cc) plants produce both chasmogamous (open) and cleistogamous (closed) flowers. Enzymes in various tissues of both cleistogamous and chasmogamous buds were detected by isozyme banding patterns in starch gel electrophoresis. The onset of cleistogamy may be signalled in the calyx and corolla tissues in the early stage of flower development. The levels of specific enzymes (PGM, PGI, G-6PD, PGD, MPI) involved in gluconeogenesis, pentose phosphate shunt and glycolysis in both calyx and corolla tissues of the cleistogamous buds were greatly reduced. These enzymes were present in the pistil and anthers of cleistogamous buds and in all floral parts of the chasmogamous buds.

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Mingbo Qin, Shanqiang Ke, Abbas Lafta, Murray E. Duysen, and Chiwon W. Lee

The relative concentrations of sucrose, glucose, and starch in the xylem and cortex tissues of carrot (Daucus carota) roots were evaluated after harvest and during storage. For the three cultivars (Apache, Bolero, Danvers 126) tested, the cortex tissue contained 76.6, 49.1, and 33.6 mg·g–1 dry weight of sucrose, glucose, and starch, respectively. In comparison, the average contents of sucrose, glucose, and starch in xylem tissues were 57.4, 52.4, and 11.6 mg·g–1 dry weight, respectively. In general, cortex tissue contained higher concentrations of sucrose and starch than the xylem tissues. The glucose concentrations in cortex and xylem were similar. In `Apache', for example, the cortex tissue contained 40% and 57% higher concentrations of sucrose and starch, respectively, than the xylem tissues, whereas glucose content of the cortex was only 7.5% higher than that of the xylem. Since sweetness is largely influenced by sucrose, the relative volume of cortex to xylem must be considered in evaluating carrot cultivars for sweet taste.

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Joel G. Reiten, Chiwon W. Lee, Z.M. Cheng, and Ronald C. Smith

Seeds of a Kentucky bluegrass cultivar (Poa pratensis 'SD Common') and two native buffalograss (Buchloe dactyloides) strains, Texas (TX) selection and North Dakota (ND) selection, were tested for their germination tolerance to increasing levels of NaCl at 0, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2% in solution. Both the TX and ND strains of buffalograss exhibited a high degree of salt tolerance with the upper limit of seed germination at 2.8% NaCl (2% to 7% germination after 6 days). At high NaCl concentrations, however, percent seed germination was much greater in the ND strain than the TX strain of buffalograss. For instance, seed germination at 0.8% NaCl was 90% in ND strain and 53% in TX strain as compared to the control. Kentucky bluegrass was least tolerant to NaCl with the upper limit of seed germination at 0.4% NaCl (14.7% germination in 6 days). Seed germination in Kentucky bluegrass was completely inhibited at 0.6% NaCl.

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Keun Ho Cho, Beyoung Hwa Kwack, Moo Ryong Huh, and Chiwon W. Lee

The biomass yield, transpiration rate, and chlorophyll contents in Cymbidium goeringii plants grown under various light, temperature, and humidity conditions were investigated. Two-year-old plants potted in pine-bark medium were grown for 12 weeks during the summer months in polyethylene film-covered mini-greenhouses having four different environmental conditions: a) closed house (CH) with high humidity (95.1% RH), high light (800 μmol·m–2·s–1) and high temperature (37.5 °C), b) ventilated house (VH) with low humidity (41.4% RH), high light (800 μmol·m–2·s–1), and medium temperature (31.5 °C), c) shaded closed house (SCH) with high humidity (91.0% RH), low light (110 μmol·m–2·s–1) and medium temperature (33.3 °C), and d) shaded ventilated house (SVH) with medium humidity (61.5% RH), low light (110 μmol·m–2·s–1) and low temperature (30.5 °C). Plants grown in CH produced leaf chlorosis with 50% shorter leaves and 40% lower relative growth rate (7.9 mg/g fresh weight per day) compared to plants grown in SVH. Cymbidium plants grown in SCH or SVH showed higher leaf and root dry weights as compared to those grown in CH or VH. Leaf chlorophyll-a and -b contents as well as carbohydrate levels were the highest in plants grown in SVH, indicating the benefits of shading and ventilation. The rate of transpiration showed a quadratic response to increasing levels of leaf temperature (r 2 = 0.81), wind velocity (r 2 = 0.82), and vapor pressure deficit (VPD, r 2 = 0.91). Regression analysis revealed that the maximum transpiration rate occurred at 25.4 °C leaf temperature, 2.1 m/s wind velocity, and 2.3 kPa VPD in this experiment.

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Marcus B. Jackson, Shanqianq Ke, Barbara A. Laschkewitsch, and Chiwon W. Lee

The growing conditions of North Dakota are characterized by short frost-free seasons (< 120 days), long photoperiods, a large fluctuation in summer temperatures, and fertile soils especially in the Red River Valley region. Commercial production of vegetables in the state has been increasing with renewed interests in fresh and processed products. Currently, about 1,200 acres are devoted to vegetable production in the state with most of it conentrated in the eastern part of the state. This excludes 158,000 acres used for potato production. The top ten vegetables, excluding potato, are onion, carrot, sweet corn, squash, cabbage, red beet, muskmelon, asparagus, pumpkin, and garlic in the descending order of acreages devoted. While onions are grown mainly for fresh markets, carrots are produced for both fresh and dehydrated products. Acreages for these two crops are expected to expand, especially for supplying onions for ringing operations and carrots for dehydration and p-carotene extraction. Each year, selected cultivars of onions, carrots and other vegetables are evaluated for their performance in this northern growing environment.

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Chiwon W. Lee, Lijuan Wang, Shanqiang Ke, Mingbo Qin, and Zong-Ming Cheng

The phenotypic expression and inheritance of the rolC gene in the transgenic plants of Salpiglossis sinuata L. were investigated. The chasmogamous salpiglossis plants with solid yellow flower color (ccrrDD) were transformed with Agrobacterium tumefaciens strains LBA4404 and EHA101 carrying rolC, GUS, and NPTII genes via a leaf disc co-cultivation system. The transgenic plants were shorter in plant height, produced more branches with a compact growth habit, and developed smaller flowers and narrower leaves as compared to the control plant. While the transgenic plants showed the same corolla color and color shades as the parental line, they became male sterile. A backcross between a male-sterile transgenic plant (ccrrDD plus rolC) and a nontransformed red-flowering line (ccRRDD) produced a progeny with red flower color and the same altered growth habit as the transgenic female parent. Only 4 out of 32 plants in this progeny population showed the negative GUS staining as well as the non transgenic phenotype. These results suggest that at least two copies of the rolC gene were integrated into one homologous chromosome pair during transformation and that a cross-over event may have occurred during meiosis.