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Virginia R. Walter, Mark D. Shelton and Richard A. Cavaletto

Shipments of floral products to Pacific rim markets must meet stringent pest-free requirements. Conventional fumigation methods with methyl bromide will soon become unavailable. Studies show that controlled atmosphere (CA) environments can offer effective insect control. Currently, CA overseas marine shipping is occuring with fresh fruits and vegetables. These shipments use microprocessors to precisely control O2, CO2, temperature and relative humidity. This study is evaluating similar commercial shipments with fresh flowers and foliage under low temperature and low O2 and high CO2 atmospheres. Preliminary results with shipments conducted by TransFresh to Guam indicate that properly maintained CA shipments of 0.5 % O2 kill insects and that flowers in properly maintained atmospheres can withstand 14 days of marine shipment with minimum effect on post-harvest life. Adequate regulation of CA storage during transit seems to be the primary limitation to the expansion of floral markets using this method of shipment.

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Mark G. Lefsrud and Dean A. Kopsell

Controlled plant growing systems have consistently used the standard earth day as the radiation cycle for plant growth. However, the radiation cycle can be controlled using automated systems to regulate the exact amount of time plants are exposed to irradiation (and darkness). This experiment investigated the influence of different radiation cycle periods on plant growth and carotenoid accumulation in kale (Brassica oleracea L. var. acephala DC.). Plants were grown in a controlled environment using nutrient solutions under radiation cycle treatments of 2, 12, 24 and 48 hours, with 50% irradiance and 50% darkness during each cycle. The radiation cycles significantly affected kale fresh weight, dry weight, percent dry matter, and the accumulation of lutein, β-carotene, and chlorophyll a and b. Maximum fresh weight occurred under the 2-hour radiation cycle treatment, whereas maximum dry weight occurred under the 12-hour treatment. Maximum accumulation of lutein, β-carotene, and chlorophyll a occurred with the 12-hour radiation cycle at values of 14.5 mg/100 g, 13.1 mg/100 g, and 263.3 mg/100 g fresh weight respectively. Maximum fresh weight production of the kale was not linked to increases in chlorophyll, lutein, or β-carotene. Consumption of fruit and vegetable crops rich in lutein and β-carotene carotenoids is associated with reduced risk of cancers and aging eye diseases. Increased carotenoid concentrations in vegetable crops would therefore be expected to increase the value of these crops.

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Craig S. Charron and Carl E. Sams

Crops of the Brassicaceae contain glucosinolates(GSs), which when hydrolyzed by the enzyme myrosinase, generate products involved in cancer chemoprotection, plant defense, and plant-insect interactions. A rapid-cycling base population of B. oleracea L. was grown in a hydroponic system in a controlled environment to determine the roles of temperature, photosynthetic photon flux (PPF), and photoperiod in GS concentration and myrosinase activity. The concentration of total GSs in leaves was 44% and 114% higher at 12 and 32 °C respectively than at 22 °C under constant light of 300 μmol·m-2·s-1. The concentration of glucoraphanin, the precursor to sulforaphane, a compound with chemoprotective properties, was 5-fold higher at 32 than at 22 °C. Total GSs were ≈50% lower in roots at 12 °C and 32 than at 22 °C. Total GSs in leaves decreased 20% when PPF was increased from 200 to 400 μmol·m-2·s-1. Myrosinase activity on a fresh weight basis (activity-FW) was ≈30% higher in leaves and stems at 12 and 32 °C than at 22 °C, and ≈30% higher in leaves grown at 200 and 400 μmol·m-2·s-1 than at 300 μmol·m-2·s-1. Consideration of climatic factors that influence the glucosinolate-myrosinase system may be necessary to optimize the planting and cultivation of Brassica crops for maximum health benefits.

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Johshin Tsuruyama and Toshio Shibuya

Plug transplants of strawberry have been replacing traditional bare-root transplants despite their higher costs because the newer approach can reduce the incidence of soilborne disease and improve transplant quality under a controlled environment

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Daniel J. Barta and Theodore W. Tibbitts

An electron microprobe was used to determine tissue concentrations of Ca across 20-mm-long leaves of `Green Lakes' crisphead lettuce (Luctuca sativa L.) with and without tipburn injury. Concentrations within the fifth and 14th leaves, counted from the cotyledons, from plants grown under controlled-environment conditions were compared to concentrations within similar leaves obtained from plants grown under field conditions. Only the 14th leaf from plants grown under controlled-environment conditions developed tipburn. Injured areas on these leaves had Ca concentrations as low as 0.2 to 0.3 mg·g-1 dry weight. Uninjured areas of tipburned leaves contained from 0.4 to 0.5 mg·g-1 dry weight. Concentrations across the uninjured 14th leaf from field-grown plants averaged 1.0 mg·g-1 dry weight. Amounts across the uninjured fifth leaves from both environments averaged 1.6 mg·g-1 dry weight. In contrast, Mg concentrations were higher in injured leaves than in uninjured leaves and thus were negatively correlated with Ca concentrations. Magnesium concentrations averaged 4.7 mg·g-1 dry weight in injured leaves compared with 3.4 mg·g-1 dry weight in uninjured leaves from both environments. Magnesium concentrations were uniform across the leaf. Potassium concentrations were highest at the leaf apex and decreased toward the base and also decreased from the midrib to the margin. Potassium averaged 51 mg·g-1 dry weight in injured and uninjured leaves from both environments. No significant differences in K concentration were present between injured and uninjured leaves. This study documented that deficient concentrations of Ca were present in areas of leaf tissue developing tipburn symptoms and that concentrations were significantly higher in similar areas of other leaves that had no symptoms. This study also documented that Ca concentrations were significantly lower in enclosed leaves that exhibited tipburn symptoms than in exposed leaves that did not exhibit tipburn. Also, the amounts of Ca in plants that developed tipburn in controlled environments were lower than in plants of the same cultivar that did not develop tipburn in field plantings. The reduced levels of Ca in plants grown in controlled environments were associated with faster development rates compared with field-grown plants.

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T. Kozai, K. Yoshinaga and C. Kubota

Sweetpotato [Ipomoea batatas (L.) Lam.] has been cultivated and recognized as an important crop in many countries, including Japan. Leafy node cuttings originated from virus-free, micropropagated mother plants are widely used for propagation of sweetpotato. In the present study, plant growth and cutting propagation rates as affected by atmospheric CO2 concentration and cutting preparation (single- or multi-node cutting) were investigated. Cuttings of `Beniazuma' sweetpotato were hydroponically cultured with or without carbon dioxide enrichment (CDE) under controlled greenhouse environment. Carbon dioxide concentration inside the greenhouse was either 1000 μmol·mol–1 with CDE or 300 μmol·mol–1 without CDE. Air temperature and relative humidity were maintained at 30 ± 1C and 80 ± 10%, respectively. Growth and development rates of the cuttings were analyzed on 20th day after start of the experiment. CDE enhanced fresh and dry weights per cutting. Propagation parameters (fresh and dry weights per single mother vine, leaf development rate, and cutting propagation rate) were greater when started from single-node cuttings than from multi-node cuttings, either with or without CDE. Shoot tip removal reduced leaf development and cutting propagation rates, but it did not affect the fresh and dry weights.

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Joshua R. Gerovac, Roberto G. Lopez and Neil S. Mattson

; Argus Control Systems, White Rock, British Colombia, Canada) at Purdue and Cornell, respectively. High tunnel environment. Seven plants of each species were randomly selected during each transplant week, spaced equally in trays, and placed in an HT on

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Ryo Matsuda, Chieri Kubota, M. Lucrecia Alvarez and Guy A. Cardineau

field, greenhouse, and home garden 2nd Ed CRC Press Boca Raton, FL Kubota, C. Thomson, C.A. Wu, M. Javanmardi, J. 2006 Controlled environments for production of value-added food crops with high phytochemical concentrations: Lycopene in tomato as an

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Ockert Greyvenstein, Brent Pemberton, Terri Starman, Genhua Niu and David Byrne

being moved from the control environment into the stress environment at that critical time. Plants adapt to their environment. For example, Nerium oleander plants grown at 45/32 °C (day/night) had a different membrane lipid composition than those grown