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Kwang Jin Kim, Eun Ha Yoo, and Stanley J. Kays

air by plants. The U.S. Environmental Protection Agency (EPA) reported detection of more than 900 VOCs in the air of public buildings ( EPA, 1989 ) and in a Finnish study ( Kostiainen, 1995 ), over 200 VOCs were identified in each of 26 homes. Toluene

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Kwang Jin Kim, Eun Ha Yoo, Myeong Il Jeong, Jeong Seob Song, Seung Youn Lee, and Stanley J. Kays

Toluene is a common volatile organic compound (VOC) found in homes and offices that represents a serious health hazard. It is readily absorbed through the respiratory tract and to a lesser extent through the skin ( EPA, 1990 ). Exposure is generally

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Kwang Jin Kim, Hyun Hwan Jung, Hyo Won Seo, Jung A. Lee, and Stanley J. Kays

(chambers) of each treatment were tested. Chambers without plants were used to determine toluene and xylene losses not resulting from the plants (e.g., leakage, adsorption, chemical reactions). After removal of the media, the root volume was measured using

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Dong Sik Yang, Svoboda V. Pennisi, Ki-Cheol Son, and Stanley J. Kays

negative effect on indoor air quality ( Darlington et al., 2000 ). VOCs are generally classified as aromatic hydrocarbons (e.g., benzene, toluene, ethylbenzene, xylene), aliphatic hydrocarbons (e.g., hexane, heptane, octane, decane), halogenated

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Mung Hwa Yoo, Youn Jung Kwon, Ki-Cheol Son, and Stanley J. Kays

Foliage plants of Hedera helix L. (english ivy), Spathiphyllum wallisii Regal (peace lily), Syngonium podophyllum Schott. (nephthytis), and Cissus rhombifolia Vahl. (grape ivy) were evaluated for their ability to remove two indoor volatile organic air pollutants, benzene and toluene. Removal was monitored when the aerial portion of plants was exposed singly to 1 μL·L-1 or to 0.5 μL·L-1 of each gas in a closed environment over 6-hour periods during the day and the night. Selected physiological processes were assessed before and immediately after treatment to determine the effect of the gases on the plants. The effectiveness of plants in the removal of air pollutant(s) varied with species, time of day, and whether the gases were present singly or as a mixture. When exposed to a single gas, S. wallisii, S. podophyllum, and H. helix displayed higher removal efficiencies (ng·m-3·h-1·cm-2 leaf area) of either gas than C. rhombifolia during the day. The efficiency of removal changed when both gases were present; H. helix was substantially more effective in the removal of either benzene or toluene than the other species, with the removal of toluene more than double that of benzene. When exposed singly, the removal of both compounds was generally higher during the day than during the night for all species; however, when present simultaneously, H. helix removal efficiency during the night was similar to the day indicating that stomatal diffusion for english ivy was not a major factor. The results indicated an interaction between gases in uptake by the plant, the presence of different avenues for uptake, and the response of a single gas was not necessarily indicative of the response when other gases are present. Changes in the rates of photosynthesis, stomatal conductance, and transpiration before and after exposure indicated that the volatiles adversely affected the plants and the effects were not consistent across species and gases. Deleterious effects of volatile pollutants on indoor plants may be critical in their efficacy in improving indoor air quality and warrant further study.

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Hyojin Kim, Ho-Hyun Kim, Jae-Young Lee, Yong-Won Lee, Dong-Chun Shin, Kwang-Jin Kim, and Young-Wook Lim

formaldehyde and additional volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and xylene (BTEX) ( Craighead, 1995 ; Sullivan et al., 2001 ). Previous researchers demonstrated that the indoor levels of these airborne particles were the

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Josee Owen and K.A. Stewart

Drosera spp. are used in alternative medicine as sources of the beneficial naphthoquinone compounds plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) and 7-methyljuglone. Presently, Drosera are harvested from the wild with great detriment to bog habitats. This study focused on the development of a hydroponic rockwool culture of the sundew D. adelae. Tissue-cultured plantlets were raised as transplants in peatmoss. The transplants were planted directly into rockwool slabs primed to pH 6. Three levels of ammonium nitrate fertilizer were applied, the highest level of which approximated natural peat bog levels. Growth and development of the plants was monitored. Plants from each nitrogen treatment were harvested and subjected to extraction with toluene. Subsequently, high-performance gas chromatography was used to separate and quantify the naphthoquinones present in the extract. This method was used for three harvests: harvest of transplants, harvest after 2 months, and after 4 months of active growth.

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Liangli Yu, Denys J. Charles, Jules Janick, and James E. Simon

The aroma volatiles of ripe fresh `GoldRush' and `Golden Delicious' apples (Malus ×domestica Borkh) were examined using dynamic headspace to capture the volatiles and gas chromatography (GC)–GC–mass spectroscopy (MS) analysis for compound identification. A total of 21 aroma volatiles were identified, with 16 being common to both cultivars: toluene, butyl acetate, hexyl formate, 2-methylbutyl acetate, xylene, butyl propionate, pentyl acetate, s-butyl butanoate, hexyl acetate, iso-butyl 2-methylbutanoate, hexyl propionate, hexyl butanoate, hexyl 2-methylbutanoate, hexyl hexanoate, a-farnesene, and ethyl phthalate. Three volatiles [dipropyl disulfide, pentyl 2-methylpropionate, and 2,6-bis(1,1-dimethylethyl)-2,5-cyclohexadiene-1,4-dione] were unique to `Golden Delicious'; two compounds (nonanal and nerolidol) were unique to `GoldRush'. Most identified compounds were esters. Hexyl acetate (18.39%) was the major volatile in `Golden Delicious', while butyl acetate (13.40%) was the highest in `GoldRush'.

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Shimon Meir, Sonia Philosoph-Hadas, and Nehemia Aharoni

Abbreviations: BHT, butylated hydroxy toluene; FCs, fluorescent compounds; MDA, malondialdehyde; PUFA, polyunsaturated fatty acids; TBA, thiobarbituric acid. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan

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Jocelyn A. Ozga and F.G. Dennis Jr.

Exposure of stratified apple (Malus domestics Borkh. cv. Golden Delicious) seeds to 30C induces secondary dormancy. To determine if an increase in abscisic acid (ABA) content was associated with the loss in germination capacity, stratified seeds (3,- 6, or 9 weeks at 5C) were held at 30C for 0, 3, or 6 days. Stratification at 5C either had no effect or increased ABA content in embryonic axes, cotyledons, and seed coats. Exposure to 30C after stratification either did not affect or decreased ABA content of embryonic axes and seed coats; in contrast, cotyledonary ABA was increased. Seed coats, cotyledons, and embryonic axes stratified for 3, 6, or 9 weeks at 20C contained the same or higher levels of ABA in comparison with nonstratified seeds or seeds stratified at SC. Changes in ABA levels were not consistently correlated with changes in germination capacity during stratification or after exposure to 30C. These data suggest that changes in ABA are not related to changes in dormancy. Chemical names used: abscisic acid (ABA); butylated hydroxy-toluene (BHT); n-(trichloromethyl) thio-4-cyclohexene-1,2-dicarboximide(Captan).