• Korean Journal of Environmental Agriculture
• /
• v.23 no.3
• /
• pp.128-132
• /
• 2004

Ozone effects were studied by plant growth chamber to evaluate the impact of ozone ($O_3$) on the physiology of two hot pepper, Capsicum annuum L., cultivars, 'Dabotab' and 'Buchon'. Forty-day old plants with $5{\sim}7$ leaves were exposed to $O_3$ of <20 and 150 nL/L for 8h/d for 3 days. Net photosynthesis and stomatal conductance were measured and foliar injury was described. Foliar damage due to the treated $O_3$ was different from the varieties. 'Dabotab' was most sensitive to $O_3$ and 'Buchon' was resistant. Symptom of ozone damage on the leaves was bifacial necrosis. Decreases of net photosynthesis by $O_3$ were 56% and 40% on 'Dabotab' and 'Buchon', respectively. Decreases of stomatal conductance by $O_3$ were 66% and 63% on each variety. $O_3$ damage on net photosynthesis was started at the low levels of light on the two hot peppers. In addition, assimilation-internal $CO_2$ concentration curves were not different from the two varieties. In conclusion, $O_3$ closed the stomata and decrease net photosynthesis on hot peppers regardless of the ozone sensitivity on leaf injury, but the difference of ecophysiological responses between the two varieties was not found clearly.

• Journal of Korean Society for Atmospheric Environment
• /
• v.8 no.1
• /
• pp.7-12
• /
• 1992

This study was conducted to determine the effectiveness of silver thiosulfate(STS) in reducing $O_3$ injury to tomato plants(Lycopersicon esculentm Mill. 'Pink Glory'). Two days prior to $O_3$ fumigation, plants were given a foliar spray of STS solution at concentrations of 0, 0.2, 0.4, 0.6 mM contained with 0.05% Tween-20. STS concentrations below 0.6 mM were significantly effective in providing protection aginst $O_3$ exposure(16 h at 0.3 ppm). STS reduced leaf injury rate, defoliation of cotyledons, ethylene production and degree of epinasty induced by $O_3$ injury. STS slightly increased ethylene production in non-$O_3$-fumigated plants, but changes of chlorophyll content and transpiration rate on a whole plant basis were not observed. In $O_3$-fumigated plants, STS treatment reduced chlorophyll destruction but did not affect transpiration rate. STS treatment seemed not to affect peroxidase(POD) and superoxide dismutase (SOD) activity in non-fumigated plants but reduced increasing activity of POD by $O_3$ fumigation. However, such an effect as above was not found in SOD activity. Even though enzymatic protection effects were not confirmed, the fact that reduction of acute injury rate was attained for 16 h fumigation indicates that the phytoprotective effects of STS are not necessarily related to blocking the action of strees-induced-ethylene as an anti-ethylene agent.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.2 no.4
• /
• pp.167-174
• /
• 2000

A glass chamber experiment was conducted to evaluate the impact of ozone (O$_3$) on the physiology of two soybean, Glycine max L. cultivars, 'Hwanggum' and 'Jangyub'. Thirty-day old plants with 1-2 nodes were exposed to $O_3$ of <10 and 150 n1 1$^{-1}$ in the chambers for 8 h d$^{-1}$ for 3 days. Net photosynthesis, stomatal conductance, chlorophyll a, chlorophyll b and total chlorophyll contents, and foliar injury (% injured leaves) were measured. Although foliar damage was more severe on Jangyub than on Hwanggum, net photosynthesis was decreased by 60% on Hwanggum and 13% on Jangyub due to the $O_3$ treatment. Stomatal conductance on Jangyub was twice higher than that on Hwanggum and it was not changed by the $O_3$ treatment. Whereas, stomatal conductance on Hwanggum was 60-80% decreased by $O_3$, Chlorophyll contents did not change due to the $O_3$ treatment or variety. We can conclude that the reduction of net photosynthesis by $O_3$ was mainly due to the decreases of stomatal conductance and Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) activity on dark reaction. And foliar injury and chlorophyll content did not contribute to the net photosynthetic decrease. The gas-exchange variables measured 24 h after the termination of $O_3$ fumigation showed that there was no significant recovery within a day. Since the physiological responses on Jangyub were not much affected by the $O_3$ treatment, this variety could be $O_3$ resistant.

• Journal of Plant Biology
• /
• v.38 no.1
• /
• pp.79-86
• /
• 1995

Visible injury symptoms such as necrosis, chlorosis and premature senscence in the leaves of Ginkgo bloba and Pinus thunbergii treated with acid rain of pH 3.2 or below were observed. The epicuticular wax erosions were observed by SEM after exposure to acid rain of pH 2.4 and 3.2 in G. biloba and pH 4.0 below in P. thunbergii. The adaxial epidennal cells and sponge parenchyma cells were compressed, and those were distorted in the leaves of G. biloba treated with simulated acid rain of pH 3.2 or below. However, vascular tissue was intact. With increase of acidity, mesophyll cells were smaller than those of control while intercellular space in mesophyU was increased. In P. thunbergii, sponge parenchyma cells and vascular tissue except epidennis were distorted after exposure to acid rain of pH 2.4. The size change of stomata in foliar injury was not observed, but the stomatal index and size of stomatal aperture in leaves treated with acid rain increased. The stomata of injured leaf were opened in both species examined.amined.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.10 no.4
• /
• pp.132-140
• /
• 2008

Two different sensitivity classes of black cherry (Prunus serotina) under the natural growing environmental conditions were assessed adjacent to Air Monitoring Station located at Horton research center in Giles County, Virginia, USA. Ambient ozone concentrations, leaf gas exchange, and visible foliar injury were measured on-site during the growing seasons of 2000, 2001, and 2002. Ambient ozone exposures were sufficient to induce typical foliar visible injury corresponding with the reduction in photosynthetic activities only in sensitive black cherry. There were positive correlations between increasing cumulative ozone concentration and percent reduction in maximum net photosynthetic rates ($Pn_{MAX}$) under saturating light conditions and in quantum yield for carbon reduction (${\Phi}CO_2$) of sensitive black cherry compared to tolerant black cherry. There was a negative correlation between chlorophyll content and percent leaf injury in sensitive black cherry. Furthermore, $Pn_{MAX}$ was inversely related to percent leaf injury.

• Korean Journal of Medicinal Crop Science
• /
• v.3 no.2
• /
• pp.146-150
• /
• 1995

Weed control in the Korean ginseng(Panax ginseng C.A. Meyer) garden is more difficult than in other crops because the ginseng is a perennial crop and has to be cultivated under the artificial shading. As hand weeding is the only practical means to control weed after crop establishment, a selective herbicide would greatly simplify the control of weed in ginseng garden. In an exploratory experiment, the hervicide Fluazifop-butyl was found to be selectively safe for the Korean ginseng plants. Various rates of Fluazifop-butyl were sprayed on 2-, 3-, and 4-years old ginseng plants as a foliar spray to detect crop injury and to difine their critical concentration. No apparent injury to the ginseng plant was noticable even the doubled application rate of Fluazifop-butyl the based on recommended dosage. Neither abnormal foliar change nor any inhibition in leaf and stem growth was resulted for 2-, 3-, and 4-years old ginseng plants treated with Fluazifop-butyl tripled the recommended usage. The foliar treatments of Fluazifop-butyl did not influence the photosynthesis ability but inhibited the respiration of the ginseng leaf.

• Horticultural Science & Technology
• /
• v.29 no.4
• /
• pp.298-305
• /
• 2011

This study was conducted to enhance the stem firmness of standard chrysanthemum 'Baekma' bred in Korea for commercial quality improvement and inhibition of stem breaking during transportation through foliar spray with calcium agents. Calcium agent screening 'Baekma' was examined using $CaCl_2{\cdot}2H_2O$, $Ca(NO_3)_2{\cdot}4H_2O$, and OS-Ca (natural liquid calcium compounds extracted from oyster shell) depending on each concentration (0, 0.001, 0.01, 0.1, and 1.0%, respectively). All calcium agents sprayed with 1.0% caused chemical injury such as stem bending or leaf burn. OS-Ca also showed more sensitive response to chemical injury than the other calcium agents because OS-Ca was absorbed very well by 'Baekma' leaves. Maximum stem firmness measured during the final harvest was greater in OS-Ca than in the other calcium agents. Especially, maximum stem firmness was greatest in 0.01% OS-Ca. However, elastic strength and maximum bending stress were greater in 0.001% OS-Ca than in the others. Thus, OS-Ca ranged from 0.005 to 0.05%, which did not show any chemical injury, was finally selected as the first candidate for hardening the stem of 'Baekma'. The next experiment using OS-Ca was conducted with the concentrations of 0, 0.005, 0.01, and 0.05%, respectively. From the results, 0.05% OS-Ca showed better plant growth and parameters such as plant height, stem diameter (upper and middle part), the number of leaves, and dry weights of each part than the other concentrations of OS-Ca and control. As for stem firmness depending on OS-Ca concentration, the Ca content within stem, maximum firmness, elastic strength, and maximum bending stress of stem in 'Baekma' sprayed with 0.05% OS-Ca showed the highest values among all the treatments and it turned out to be very high level of significance between control and OS-Ca treatments. However, the area and percentage of the inside cavity within horizontal stem section in 'Baekma' did not show any significance between any treatments including control. Thus, stem firmness of 'Baekma' did not show any correlation with the inside cavity area of stem. In conclusion, we recommend foliar sprays with 0.05% OS-Ca at vegetative growth stage to enhance stem firmness of 'Baekma' during transportation.

• Food preservation and processing industry
• /
• v.3 no.1
• /
• pp.42-46
• /
• 2004

Quality of fresh-cut tomato slices was compared during cold storage under various modified atmosphere packaging conditions. Chilling injury of slices in containers sealed with Film A was higher than with Film B; these films had oxygen transmission rates of 87.4 and 60.0 ml h-1 m-2 nun-1 at $5^{\circ}C$ and $99\%$ RH, respectively. While slices in containers with an initial atmospheric composition of air, $4\%$ CO2 + 1 or $20\%\;O_2, \;8\%\;CO_2+1$ or $20\%\;O_2$, or $12\%\; CO_2+\;20\%\;O_2$ showed fungal growth, slices in containers with $12\%\;CO_2 +\;1\%\;O_2$ did not. Low ethylene in containers enhanced chilling injury. Modified atmosphere packaging provided good quality tomato slices with a shelf-life of 2 weeks or more at $5^{\circ}C$. Experiments were conducted to compare changes in quality of slices of red tomato (Lycopersicon esculentum Mill. 'Sunbeam') fruit from plants grown using black polyethylene or hairy vetch mulches under various foliar disease management systems including: no fungicide applications (NF), a disease forecasting model (Tom-Cast), and weekly fungicide applications (WF), during storage at $5^{\circ}C$ under a modified atmosphere. Slices were analyzed for firmness, soluble solids content (SCC), titratable acidity (TA), pH, electrolyte leakage, fungi, yeasts, and chilling injury. With both NF and Tom-Cast fungicide treatments, slices from tomato fruit grown with hairy vetch (Vicia villosa Roth) mulch were firmer than those from tomato fruit grown with black polyethylene mulch after 12 days storage. Ethylene Production of slices from fruit grown using hairy vetch mulch under Tom-Cast was about 1.5- and 5-fold higher than that of slices from WF and NF fungicide treatments after 12 days, respectively. The percentage of water-soaked areas (chilling injury) for slices from tomato fruit grown.

• Korean Journal Plant Pathology
• /
• v.11 no.3
• /
• pp.210-216
• /
• 1995

Alternaria spp.were predominantly isolated from the abnormal leaf spot lesions of pear cultivars Niitaka and Nijiiseiki. Alternaria isolates from the cultivar Niitaka were not pathogenic to both cultivars, but the isolates from the cultivar Nijiiseiki developed typical lesions of black leaf spots and were identified as A. kikuchiana. However, no typical abnormal leaf spot lesions were produced by the Alternaria isolates. Foliar spray of twelve different agrochemicals including lime sulfur, either alone or in combinations, with 7 times applications from April to July failed to reduced the disease development. Application of 17 different pesticides including fungicides, insecticides and herbicides currently used in pear orchards did not cause leaf injury similar to the abnormal leaf spot. Simulated acid rain of as low as pH 3.0 did not incite any leaf lesions alike the abnormal spot lesions. Mineral contents in the leaves of both cultivars did not differ significantly between the healthy leaves and those with abnormal leaf spots. When cuttings of pear tree were obtained in February from newly emerged twigs of the healthy or the diseased trees of Niitaka and planted in sand in the greenhouse, only those from the diseased trees developed typical leaf lesions of the abnormal spot. These results indicate that abnormal leaf spots are caused by unknown systemic agents in pear trees, rather than by Alternaria spp., chemical injury or acid rain.

• Korean Journal of Environmental Agriculture
• /
• v.7 no.1
• /
• pp.52-57
• /
• 1988

This study was carried out to investigate the specific activity fo peroxidase(POD) in conjunction with the phytotoxic effect of the tolerant soybean(Glycine max Merr.) and the susceptible crabgrass(Digitaria adscendens(L.) Scopol.) to acifluorfen. The POD activity increased during the growth of soybean and crabgrass seedlings. But after the foliar application of acifluorfen, the POD activity in the treated leaves was considerably higher than in controlled leaves, suggesting that soybean had higher tolerance to acifluorfen with growth. All the treated soybeans recovered from herbicidal injury in 14 days after treatment, while all the treated crabgrasses were dead with extreme necrosis and leaf burning. It was measured that the POD activity of crabgrass increased abruptly in 1 to 2 days after treatment and then significantly decreased in 5 days.