• Journal of The Korean Society of Agricultural Engineers
• /
• v.61 no.6
• /
• pp.9-19
• /
• 2019

Vegetative Filter Strip (VFS) is the best management practice which has been widely used to mitigate water pollutants from agricultural fields by alleviating runoff and sediment. This study was conducted to improve an equation for estimating sediment trapping efficiency of VFS using several different regularization methods (i.e., ordinary least squares analysis, LASSO, ridge regression analysis and elastic net). The four different regularization methods were employed to develop the sediment trapping efficiency equation of VFS. Each regularization method indicated high accuracy in estimating the sediment trapping efficiency of VFS. Among the four regularization methods, the ridge method showed the most accurate results according to $R^2$, RMSE and MAPE which were 0.94, 7.31% and 14.63%, respectively. The equation developed in this study can be applied in watershed-scale hydrological models in order to estimate the sediment trapping efficiency of VFS in agricultural fields for an effective watershed management in Korea.

• The Plant Pathology Journal
• /
• v.35 no.5
• /
• pp.393-405
• /
• 2019

Survival factor 1 (Svf1) is a protein involved in cell survival pathways. In Saccharomyces cerevisiae, Svf1 is required for the diauxic growth shift and survival under stress conditions. In this study, we characterized the role of FgSvf1, the Svf1 homolog in the homothallic ascomycete fungus Fusarium graminearum. In the FgSvf1 deletion mutant, conidial germination was delayed, vegetative growth was reduced, and pathogenicity was completely abolished. Although the FgSvf1 deletion mutant produced perithecia, the normal maturation of ascospore was dismissed in deletion mutant. The FgSvf1 deletion mutant also showed reduced resistance to osmotic, fungicide, and cold stress and reduced sensitivity to oxidative stress when compared to the wild-type strain. In addition, we showed that FgSvf1 affects glycolysis, which results in the abnormal vegetative growth in the FgSvf1 deletion mutant. Further, intracellular reactive oxygen species (ROS) accumulated in the FgSvf1 deletion mutant, and this accumulated ROS might be related to the reduced sensitivity to oxidative stress and the reduced resistance to cold stress and fungicide stress. Overall, understanding the role of FgSvf1 in F. graminearum provides a new target to control F. graminearum infections in fields.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.22 no.1
• /
• pp.47-59
• /
• 2019

This study was composed of four treatments [no treatment, phosphate + limestone layer treatment, phosphate + sodium bicarbonate + cement layer treatment, and phosphate + sodium bicarbonate + limestone layer treatment] for figuring out vegetation effects on the acid drainage slope. Treated acid neutralizing techniques were effective for neutralizing acidity and vegetative growth in order of [first: phosphate + sodium bicarbonate + limestone layer treatment, second: phosphate + sodium bicarbonate+cement layer treatment, third: phosphate + limestone layer treatment and fourth: no treatment] on the acid drainage slope. We found out that sodium bicarbonate treatment was additory effect on neutralizing acidity and increasing vegetaive growth besides phosphate and neutralizing layer treatments. In neutralizing layer treatments, Limestone layer was more effective for vegetation and acidity compared to cement layer treatment. Cement layer showed negative initial vegetative growth probably due to high soil hardness and toxicity in spite of acid neutralizing effect. Concerning plants growth characteristics, The surface coverage rates of herbaceous plants, namely as Lotus corniculatus var. japonicus and Coreopsis drummondii L were high in the phosphate + sodium bicarbonate + limestone layer treatment while Festuca arundinacea was high in the phosphate + sodium bicarbonate + cement layer treatment. We also figured out that soil acidity affected more on root than top vegetative growth.

• Horticultural Science & Technology
• /
• v.16 no.2
• /
• pp.247-250
• /
• 1998

This study was carried out to investigate the effects of changes of ionic strength according to growth stage on growth and flowering of Dendranthema grandiflorum (Ramat.) Kitamura 'Seiun' grown hydroponically in perlite. The stage I, II, and III covered early vegetative growth (27-40 days after planting), latter vegetative growth (41-54 days), and reproductive growth (55-80 days), respectively. The 2 strength (1S and 2S) of nutrient solution were treated in stage I, whereas 3 strengths (1S, 1-2S, and 2S) were treated in stage II. Then, total 9 treatments in stage III were designated by 3 treatments (tap water, 1S, and 2S) for each 3 strengths in stage II. Each nutrient solution was applied 8 times per day. At vegetative growth stage (54 days after planting), stem length was highest when irrigated 8 times a day with 1S nutrient solution. Both photosynthesis and transpiration rate were higher in 1S than those in other treatments (1-2S, 2S), whereas leaf chlorophyll content was highest in 2S treatment. Ion content of plant treated with 2S was higher than other treatments. Growth (plant height, leaf area, stem length), fresh weight, and dry weight of each plant organ after flower bud formation were better in tap water treatment (1-1-0) than other 1S treatments (1-1-1, 1-1-2). Regarding the number of days to flowering, tap water treatment was the most effective. Thus, after flower bud formation supplying tap water or lower concentration of nutrient solution than those used during the vegetative growth stage was economical in saving chemical fertilizers, shortening the number of days to flowering, reducing salt accumulation in media, saving efforts of leaching, and reducing ground water contamination.

• 한국생태학회:학술대회논문집
• /
• 1999.05a
• /
• pp.97.2-97.2
• /
• 1999

• Proceedings of the Korean Society of Environment and Ecology Conference
• /
• 2002.04a
• /
• pp.53-55
• /
• 2002

• Fisheries and Aquatic Sciences
• /
• v.2 no.1
• /
• pp.25-31
• /
• 1999

Developmental morphology of the red alga, Osmundea crispa (Hollenberg) Nam from California was studied on the basis of liquid-preserved and herbarium specimens. Vegetative axial segment of the species produces two pericentral cells and one trichoblast. Spermatangial filaments (branches) are derived from apical and epidermal cells in pocket-shaped apical pit with an ostiole-like upper opening. Procarp-bearing segment of female trichoblast produces five pericentral cells, of which the fifth functions as supporting cell of carpogonial branch. Tetrasporangial production occurs in random epidermal cells in apical pit of branchlets, and two presporangial cover cells show parallel arrangement to stichidial axis. As this vegetative and reproductive development is included in the generic delineation of Osmundea Stackhouse, O. crispa among the known Osmundea species is characterized by habit forming compact cushion-like clump with angular to terete thallus. It is also distinguished from O. hybrida (AP. de Candolle) Nam without the compressed thallus by the number of pericentral cells in procarp-bearing segment and shape of spermatangial pit. Taxonomic implication of the shape of spermatangial pit is also included.

• Mycobiology
• /
• v.42 no.1
• /
• pp.1-5
• /
• 2014

The typical life cycle of filamentous fungi commonly involves asexual sporulation after vegetative growth in response to environmental factors. The production of asexual spores is critical in the life cycle of most filamentous fungi. Normally, conidia are produced from vegetative hyphae (termed mycelia). However, fungal species subjected to stress conditions exhibit an extremely simplified asexual life cycle, in which the conidia that germinate directly generate further conidia, without forming mycelia. This phenomenon has been termed as microcycle conidiation, and to date has been reported in more than 100 fungal species. In this review, first, we present the morphological properties of fungi during microcycle conidiation, and divide microcycle conidiation into four simple categories, even though fungal species exhibit a wide variety of morphological differences during microcycle conidiogenesis. Second, we describe the factors that influence microcycle conidiation in various fungal species, and present recent genetic studies that have identified the genes responsible for this process. Finally, we discuss the biological meaning and application of microcycle conidiation.

• Applied Microscopy
• /
• v.44 no.2
• /
• pp.41-46
• /
• 2014

In this study, the vegetative and reproductive morphology and anatomy of two Hawaiian endemic Portulaca species were examined. Specifically, P. molokiniensis and P. sclerocarpa were compared to closely related species in the genus. The comparisons were both qualitative and quantitative, using characteristics of leaves, stems, roots, and fruits. Tissue organizations of vegetative and reproductive parts of the plants were assessed using microtechnique procedures, statistical analysis, and scanning electron microscopy. The most notable features of these two species were (1) the size and frequency of stomata in P. molokiniensis, and (2) the large number of sclerenchymatous cell layers in the thickest fruit walls of P. sclerocarpa. These findings may imply that stomata development in P. molokiniensis and thick fruit wall development in P. sclerocarpa are evolved features of survival. In particular, the development of thickened walls in indehiscent fruits likely has evolutionary implications of ecological tolerance for better adaptation.

• Korean Journal Plant Pathology
• /
• v.11 no.4
• /
• pp.330-337
• /
• 1995

Forty-six isolates of Fusarium oxysporum collected from infected tomato plants and soils in greenhouses in Sedo, Chungnam and Angang, Kyeongbuk and 8 isolates of F. oxysporum f. sp. lycopersici from Japan and USA were used to determine vegetative compatibility groups (VCGs). Vegetative comaptibility was assessed on the basis of heterokaryon formation among nitrate nonutilizing mutants. All Korean isolates of F. oxysporum f. sp. lycopersici used in this study belonged to the same type of VCG (003) regardless of their geographic origin, cultivar and race, but they were incompatible with the foreign isolates of VCG 0030, 0031, 0032 and 0033. Based on the results, the Korean isolates of F. oxysporum f. sp. lycopersici were classified as a new VCG 003.