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species was conducted as a separate experiment and included an untreated control, DS (Augeo, 18% dikegulac sodium; OHP, Inc., Mainland, PA) at 400 mg·L −1 , 800 mg·L −1 , or 1600 mg·L −1 ; BA (Configure, 2% benzyladenine; Fine Americas, Inc., Walnut Creek

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using 20N-4.4P-16.6K Peters Professional General Purpose fertilizer (The Scotts Co. LLC, Marysville, OH). Benzyladenine (Configure; Fine Americas, Inc., Walnut Creek, CA) was applied to liners at least 8 h after removal from mist. This was considered the

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applications that are available as free software under the GNU General Public License terms ( GNU Project, 2007 ). Development of web interface. The database web interface was configured using Dadabik ( Tacchini, 2007 ), a hypertext preprocessor (PHP

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. The RW−Fr treatment was applied during 0–75 DAS in the early growth stage and RW+Fr afterward until the final harvest (at 105 DAS). RW−Fr was configured by covering the Fr lamps. The RW+Fr treatment was configured by removing the covers to provide the

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Web-based information delivers real-time or near-real-time data to clientele and other stakeholders. Although proprietary methods are available for interactively searching and updating databases through web interfaces, these methods generally require varying costs to maintain licensing agreements. The availability of publicly available software that require minimal or flexible licensing costs provide a cost-effective alternative to institutions that are considering access to databases via a web-accessible interface. For example, if a current web server is already configured to support hypertext preprocessor (PHP) scripts and MySQL databases, all that needs to be installed is a form script to allow the searching, inserting, and deleting of records. We describe procedures, software, and other applications that we used to develop a publicly accessible web interface to an experimental database of representative sweetpotato accessions in Kenya. The web address of this database is http://www.viazivitamu.org. This site also contains links to sweetpotato collection sites in Kenya, Tanzania, and Uganda graphically shown using a public domain GIS viewer. This demonstrates that public domain web-based tools can be configured not only to support collaborative activities among researchers in various locations, but also to provide relevant data to clients and other stakeholders.

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Chambers were developed to study the uptake, accumulation and phytotoxicity of environmental pollutants. Each is connected to the computer and other support facilities by quick connects which allow the laboratory to be configured in various ways depending on experimental design. Each chamber consists of two isolation compartments connected only by plant stems. Electronic instruments are used to monitor key physiological processes of both the roots and shoots during the course of plant exposure. The computer controls the exposure conditions (i.e. day length, temperature, nutrient pH, CO2 concentration, etc.) as well as continuously collects information about plant responses (i.e. photosynthetic and transpiration rates). Photosynthesis, transpiration, and mineral nutrient uptake can be individually controlled by manipulating the environment and thus allowing their study in combination with additional stressors. The computer used to accomplish these tasks will be discussed along with other examples of computer use for plant manipulation.

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Chambers were developed to study the uptake, accumulation and phytotoxicity of environmental pollutants. Each is connected to the computer and other support facilities by quick connects which allow the laboratory to be configured in various ways depending on experimental design. Each chamber consists of two isolation compartments connected only by plant stems. Electronic instruments are used to monitor key physiological processes of both the roots and shoots during the course of plant exposure. The computer controls the exposure conditions (i.e. day length, temperature, nutrient pH, CO2 concentration, etc.) as well as continuously collects information about plant responses (i.e. photosynthetic and transpiration rates). Photosynthesis, transpiration, and mineral nutrient uptake can be individually controlled by manipulating the environment and thus allowing their study in combination with additional stressors. The computer used to accomplish these tasks will be discussed along with other examples of computer use for plant manipulation.

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Overhead mist (OM) facilitates the propagation of stem cuttings by preventing transpirational water loss. However, drawbacks to OM include the application of large volumes of water, potentially unsanitary conditions, irregular misting coverage, and leaching of foliar nutrients. We explored three alternatives to OM that might avoid these problems by applying moisture below, rather than overhead. These included 1) a submist (SM) aeroponic system configured to provide intermittent mist only to the rooting zone, 2) a subirrigation (SI) system that provided water via capillary action through perlite from a reservoir maintained below the base of each cutting, and 3) a subfog (SF) aeroponic system that was configured to provide constant fog only to the rooting zone. To initiate each system, we wetted perlite or filled reservoirs using either water or quarter-strength Hoagland solution. Stem cuttings of ‘Wizard Mix’ coleus (Plectranthus scutellarioides) were propagated in the systems for 21 days. Cuttings in the SM system produced more than three times as many roots as cuttings in the OM system, with roots more than six times the length. Root dry weights averaged 28 mg for cuttings in the SM system, compared with only 3.5 mg among cuttings receiving OM. The SF and SI systems produced results broadly comparable to the OM. Fertilizer did not consistently improve rooting measures across the systems. Although we observed few fine roots on cuttings rooted using SM, they transplanted well into a soilless substrate and quickly produced new root growth. The SM system used less than 1/5 the water used by the SI system, and less than 1/50 the water used by the SF system. In comparison, a single OM nozzle operating for 10 seconds released about one-third of the total water lost through transpiration from each SM system over the entire experiment. Our results show that SM systems merit further evaluation for propagation of plants by stem cuttings.

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In areas of California with a high incidence of walnut blackline disease, walnut orchards are increasingly being planted on English walnut (Juglans regia) rootstocks that are tolerant to the virus. There is limited documentation on the salt tolerance of this rootstock. This work was done to quantify the response of English walnut rootstocks to high boron (B), chloride (Cl), and sodium (Na) and to compare this to the more common rootstocks, Northern California Black (J.hindsii) and Paradox (J. hindsii × J. regia). The trial was configured as a randomized complete-block design with 20 plots. Plots consisted of three proximate, matched `Chandler' trees, each on a different rootstock. Leaf samples over a 2-year period showed that trees on the English rootstock had a significantly higher salt uptake than trees on Paradox, which had a significantly higher uptake than trees on Black. Bark cores showed little difference in B uptake between any of the rootstocks. Bark cores also showed that all rootstocks accumulated significantly more B than the scion portion of the tree, indicating that B transport may be limited by the graft union. Trees on English rootstock had significantly more B in the scion bark cores than trees on either Black or Paradox, indicating that rootstocks with a J. hindsii parent may be better at reducing salt transport across the graft union.

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Aquaponics, the combination of hydroponics and aquaculture into one growing system, is a controlled environment production system that potentially has increased environmental and consumer benefits over traditional production methods. There are many different ways to configure aquaponics systems that include different fish species, water circulation, lighting, plant species/density, and more. We tested three cultivars of lettuce, a common aquaponically produced crop, for yield in multiple aquaponic systems and conditions over a 13-month period in Minnesota. Four different aquaponic configurations and four types of fish were tested over the course of the experiment. There was no addition of supplemental nutrients to the systems to evaluate the differences between treatments and set a baseline. There was no difference in yield between lettuce produced aquaponically and those grown in soilless medium. However, there was a difference in yield between lettuce grown with different fish treatments. The tilapia treatment produced higher average yield than yellow perch. There was a difference between cultivars, with higher average yield from loose-leaf bunch cultivars (Salanova, Skyphos) than the bibb type (Rex). Average yield for all but one treatment was above that of reported commercial field production, making lettuce a competitive aquaponic crop in most systems.

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