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Rocío Leyva, Christian Constán-Aguilar, Begoña Blasco, Eva Sánchez-Rodríguez, Teresa Soriano, and Juan M. Ruíz

relation to tomato yield under different environmental conditions using fogging as well as combining fogging with additional plastic sheeting over the screenhouse and assessing the repercussions on oxidative metabolism, Pro metabolism, and free PA

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Robert H. Stamps, Seenivasan Natarajan, Lawrence R. Parsons, and Jianjun Chen

-based cold protection systems at these locations ( Fig. 1 ) used mist and fog emitters rather than conventional overhead irrigation systems. Water application rates for cold protection based on shadehouse areas and volumes ranged from 6,919 to 160,810 L·ha −1

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Y. Zhang and J.L. Shipp

This study investigated greenhouse and plant surface microclimate for cucumber crops (Cucumis sativus) under high pressure overhead fogging. Overhead fogging maintained greenhouse humidity above its set point and avoided excessively low humidity conditions on sunny days. Fogging caused minimal to moderate changes in greenhouse air temperature in the fall depending on whether or not the leaves were sunlit or shaded. The temperature of sunlit leaves decreased by 1 to 1.5 °C (1.8 to 2.7 °F) under occasional fogging in the morning and by 3 °C (5.4 °F) under extensive fogging during noon hours. The temperature of fogged shaded leaves did not significantly change (<1 °C) when compared to nonfogged shaded leaves. Leaf wetness duration (LWD) was extended when overhead fogging was used. The length of extended daytime wetness duration (LWDday) from 0800 to 1700 HR in the fogged greenhouse depended primarily on global radiation at the leaf level. A simulation model was developed to predict LWDday using daily integrated global radiation (Rsum) as the input.

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Bryan J. Peterson, Olivia Sanchez, Stephanie E. Burnett, and Darren J. Hayes

for propagation of plants by stem cuttings, with promising results ( Mehandru et al., 2014 ). Another aeroponic product on the market (Cyclone Ultrasonic Fogger; FutureGarden, Lindenhurst, NY) can be used to supply a fog of nebulized water or

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R.M. Skirvin and S. Sriskandarajah

Acclimatization and growth of in vitro-derived apple shoots of two apple scion apple cultivars were compared under fogged conditions in a greenhouse and in a commercial growth cabinet (Phototron). Plant survival rates of microcuttings of `Royal Gala' and `Jonagold' were significantly better when maintained in the Phototron units than when grown in a greenhouse under fog. The number and length of roots on microcuttings was significantly higher in the Phototron than under fog. In the present study, we demonstrated that the Phototron environment was better than a fogged greenhouse for establishing apple shoots ex vitro. However, the Phototron units are so small that they hold no more than 100 to 120 plants at a time. Therefore, the units will be of most value to growers or individuals in laboratories who do not have a constant need for acclimatization facilities. Growers who acclimatize many plants should continue to use fogging or misting facilities.

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Brent Tisserat and Robert Silman

An inexpensive ultrasonic fogging system is presented that aids in the establishment of tissue culture shoots in soil under greenhouse conditions. In addition, ultrasonic fogging may be coupled to CO2 nutrient enhancement via bubbling CO2 into the water reservoirs prior to fogging to improve growth and morphogenesis responses of shoots. A list and cost of items for the system and its assembly is given. Transplanted tissue culture shoots of basil (Ocimum basilicum L.), hosta (Hosta sp.), mint (Mentha sp.), and thyme (Thymus vulgaris L.) were tested with this fogging system with and without CO2 nutrient elevation and compared to the growth of shoots grown under a misting system with and without CO2 nutrient elevation. In all cases, ultrasonic fogging enhanced survival rates, growth (fresh weights) and morphogenesis (axially shoots, leaves and roots) vs. that occurring in the misting system. For example, thyme and mint shoots exhibited 2- and 5-fold increases, respectively, in fresh weights under ultrasonic fogging with CO2 compared to misting systems with CO2. Associated with enhanced survival and morphogenesis was an overall enhancement of shoot and leaf size and overall maturation responses. This is also reflected in enhanced secondary products obtained from shoots grown under ultrasonic fogging compared to shoots grown in misting systems.

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Hiromi Toida, Toyoki Kozai, Handarto, and Katsumi Ohyama

Fogging systems are still not widely used for greenhouse cooling, primarily due to their low fog: evaporation ratio, resulting in a low cooling efficiency and a high risk of pathogen expansion caused by excess wetness of plant foliage. The fogging is operated intermittently because of these problems. Consequently, the air temperature and relative humidity fluctuates inside the greenhouse. If nozzles with a high fog: evaporation ratio are employed, the fogging can be operated continuously. By continuous fogging, steady air temperature and relative humidity can be achieved inside the greenhouse. In our previous study under indoor conditions, a high fog: evaporation ratio was achieved by installing two small fans close to a conventional upright nozzle in order to obtain an upward air stream. The objective of this study was to draw a comparison between the environmental conditions inside a greenhouse with the continuous fogging with small fans and that with the conventional intermittent fogging without fans. Reduced fluctuation of the air temperature and relative humidity inside the greenhouse were observed in the case of continuous fogging as compared with that observed in the case of intermittent fogging. The air temperature inside the greenhouse during cooling was lower than that before cooling in both methods. In the case of continuous fogging, the adjustment of the amount of fogged water will provide the desired environmental conditions inside the greenhouse.

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Y. Zhang, L. Gauthier, D. de Halleux, B. Dansereau, S. Yelle, and A. Gosselin

qA 3-year study was undertaken to quantify the effect of four greenhouse covering materials on energy consumption, microclimate, and the growth and production of cut flowers Matthiola incana (Stocks) and Antirrhinum majalis (Snapdragons) in the greenhouse. The four materials are single glass (GL), polyethylene (PE) + anti-fog 1-year polyethylene (AF1), polyethylene + antifog 3-year polyethylene (AF3), and polyethylene + anti-fog thermal polyethylene (AFT). The effect of thermal screen and supplementary lighting (60 μmol·m–2·s–1) also are discussed. This study indicated that AFT film is the most energy efficient material and AF3 film is the most transparent to photosynthetic active radiation (PAR). For stocks, good quality can be obtained in GL and AF3 in terms of spike length, stem diameter, as well as number of buds and flowers. The stocks in GL, however, always possess the highest photosynthetic capacity, regardless light treatment. For snapdragons, the growth and flowering in PE houses were significantly improved by supplementary lighting

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Hongyi Zhang and William R. Graves

A rapid, easy, and economical way to root softwood cuttings of red maple (Acer rubrum L. and A. × freemanii E. Murray) has been developed. Single-node cuttings were treated with 8 g IBA/kg and inserted in flats of perlite. Flats were placed in larger trays without drainage holes. Cuttings were subirrigated by adding a complete solution with 100 mg N/L to trays, saturating perlite at the bottom of the flat, below the cuttings. After 3 weeks, 94, 98, 100, and 100% of cuttings of `Indian Summer', `Autumn Flame', `Red Sunset', and `Autumn Blaze' had rooted, respectively. Leaves on cuttings remained turgid without mist or fog. In a subsequent study of `Red Sunset', 0, 50, and 100 mg N/L in the subirrigation solution resulted in 37, 100, and 100% rooting with 8 g IBA/kg and 0, 43, and 67% rooting without IBA. Rooting was fastest and chlorophyll in leaves was highest with both IBA and nutrients. Subirrigation can replace mist or fog when rooting cuttings of red maple.

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Jaime Barros da Silva Filho, Paulo Cezar Rezende Fontes, Paulo Roberto Cecon, Jorge F.S. Ferreira, Milton E. McGiffen Jr., and Jonathan F. Montgomery

of buckets used to grow minitubers allowed multiple harvests without disturbing the system ( B ). Design The experiment was set up in a randomized complete block design with four replicates and eight treatments combining a misting nozzle type Fogger