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Dave Llewellyn, Katherine Schiestel, and Youbin Zheng

and LED SL treatments are shown in Fig. 1 . Fig. 1. Relative quantum flux of the high-pressure sodium (HPS; solid line) and light-emitting diode (LED; dotted line) supplemental lighting treatments over the photosynthetically active radiation spectral

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Mara Grossman, John Freeborn, Holly Scoggins, and Joyce Latimer

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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Francesco Di Gioia, Angelo Signore, Francesco Serio, and Pietro Santamaria

equivalents in the juice. For each tomato fruit sample, ≈200 g of fresh fruits were dried in a forced-air oven at 65 °C until reaching a constant mass, then weighed to calculate the fruit DM content. Sodium content was measured on tomato juice by ion

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Reid Torrance, David Langston, and Don Sumner

Metam sodium has been evaluated on onions in Georgia since the mid-1980s for control of various soil pathogens in the production of transplants. Observations also indicated excellent weed control activity. Further work showed significant growth response of transplants, 90% or better weed control, and efficacy of Phoma terrestris, Fusarium, and Pythium. Results were better in comparison studies than found with methyl bromide, chloropicrin, and other fumigation combinations. This led to use of the product in field production of dry bulb onions. Seven years of studies revealed an average yield increase of 190 bushels per acre over the control, even where Phoma terrestris levels were minimal. Today, almost all transplant production includes the use of metam sodium and field use is beginning to be used by growers. With limited crop rotation being practiced in the Vidalia onion belt, metam sodium will continue to play a major role in controlling the ever-increasing levels of Phoma terrestris and maintaining profitability in onion production in Georgia.

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Ji Jhong Chen, Haifeng Xing, Asmita Paudel, Youping Sun, Genhua Niu, and Matthew Chappell

1.31 ± 0.08 dS·m –1 (mean ± sd ) during the experiment. Sodium chloride (NaCl; Fisher Scientific, Waltham, MA) at 0.92 g·L –1 and dihydrate calcium chloride (CaCl 2 ·2H 2 O; Hi Valley Chemical, Centerville, UT) at 1.17 g·L –1 were added to the

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Francesco Giuffrida, Marianna Martorana, and Cherubino Leonardi

the ionic balance inside the plant tissue, in the functionality of the membrane, and in transport and enzymatic activities ( Flagella et al., 2002 ). Likewise, the capacity of sodium to seriously interfere with the absorption of potassium and calcium

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Matthew G. Blanchard and Erik S. Runkle

-pressure sodium (HPS), incandescent (INC), or metal halide lamps ( Whitman et al., 1998 ). An alternative method to deliver photoperiodic lighting is to truncate the period of darkness by providing night-interruption (NI) lighting ( Vince-Prue, 1975 ). During a 24

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Darren W. Lycan and Stephen E. Hart

Previous research has demonstrated that bispyribac-sodium can selectively control established annual bluegrass (Poa annua L.) in creeping bentgrass (Agrostis stolonifera L.). Annual bluegrass is also a problematic weed in other cool-season turfgrass species. However, the relative tolerance of other cool-season turfgrass species to bispyribac is not known. Field experiments were conducted at Adelphia, N.J., in 2002 and 2003 to gain understanding of the phytotoxic effects that bispyribac may have on kentucky bluegrass (Poa pratensis L.), perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea (L.) Schreb.), and chewings fine fescue (Festuca rubra L. subsp. commutata Gaud.). Single applications of bispyribac at 37 to 296 g·ha–1 were applied to mature stands of each species on 11 June, 2002 and 10 June, 2003. Visual injury was evaluated and clippings were collected 35 and 70 days after treatment (DAT). Visual injury at 35 DAT increased as bispyribac rate increased. Kentucky bluegrass was least tolerant to bispyribac with up to 28% injury when applied at 296 g·ha–1. Injury on other species did not exceed 20%. Initial injury on perennial ryegrass, tall fescue, and chewings fine fescue was primarily in the form of chlorosis, while kentucky bluegrass exhibited more severe stunting and thinning symptoms. Bispyribac at rates from 74 to 296 g·ha–1 reduced kentucky bluegrass clipping weights by 19% to 35%, respectively, as compared to the untreated control at 35 DAT in 2002. Initial visual injury on perennial ryegrass, tall fescue, and chewings fine fescue dissipated to ≤5% by 70 DAT. However, recovery of kentucky bluegrass was less complete. These studies suggest that bispyribac-sodium has potential to severely injure kentucky bluegrass. Injury on perennial ryegrass, tall fescue, and chewings fine fescue appears to be less severe and persistent; therefore, bispyribac can be used for weed control in these species. Chemical names used: 2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoic acid (bispyribac-sodium).

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C.L. Mackowiak, J.L. Garland, and R.M. Wheeler

As humans explore the solar system, life support will need to be increasingly self-sufficient. Growing higher plants and using recycling technologies can improve self-sufficiency. Sodium is an essential mineral for humans, but not typically for plants. Recycling sodium back to humans through food crops may reduce the need for sodium supplements in the human diet. However, if sodium from waste streams is added to the plant system in greater quantities than it is removed, then plant toxic levels may result. The recommended daily sodium requirement is 3000 mg per person. Based on a 20-m2 growing area per person, 150 mg·m–2 sodium would need to be removed each day. Most crops will not remove enough salt when grown at very low sodium levels; however, when grown in 20 mM sodium, plant uptake may meet the 3000 mg/d human sodium requirement without affecting yields. We grew four different salad crops (lettuce, radish, spinach, and table beet) hydroponically and calculated plant uptake rates and partitioning with 0, 20, 40, or 80 mM sodium supplemented nutrient solutions (corresponding to ≈1.4, 4.0, 8.0, and 13.0 dS·m–1 electrical conductivity). Sodium at 40 and 80 mM reduced edible yields. Sodium replaced tissue potassium in most cases, whereas calcium and magnesium concentrations were much less affected, particularly at 20 mM sodium. This data will be used to model sodium flows within a bioregenerative life support system and determine the feasibility of sodium recycling using food crops.

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J.W. Sitton, M.E Patterson, and G.W. Apel

Immersion of Anjou pears (Pyrus communis L. cv. Beurre d Anjou) in sodium lignin sulfonate (SLS), a flotation agent used in hydraulic handling of pears, did not cause injury leading to skin browning. Immersion of cut pear slices in SLS discolors pear fruit flesh, but the discoloration derived from SLS pigments does not intensify with time. When the fungicide sodium orthophenylphenate (SOPP) was combined with SLS, necrotic skin mottling occurred with increased immersion times and temperatures. A white precipitate in the SLS SOPP solution accompanied phytotoxicity of pear skin tissue. Acidification of alkaline SOPP solutions (pH 11.3) with 0.01 N HCl down to pH 10 produced mild skin necrosis. Both acid (0.01 N HC1) and alkaline (0.01 n KOH) solutions of SOPP and SLS-SOPP combinations caused browning of pear flesh.