• Korean journal of applied entomology
• /
• v.24 no.2 s.63
• /
• pp.51-60
• /
• 1985

This paper was performed to study the nature of varietal resistance of some Korean-new rice cultivars to the brown planthopper (BPH), Nilaparvata lugens ($ST{\AA}L$). The rice cultivars tested were Cheongcheong, Gaya, Hangangchal, Samgang, Nampoong and Yeongpoong which have been reported as having resistant genes for the BPH. The check varieties were Jinheung, Sangpoong and Chucheong for susceptible and IR-36 for resistant. The factors studied were referred to the seedling responses, preference in feeding and oviposition of BPH, antibiosis (nymphal development, adult emergence and sex ratio, adult body weight, population build-up, feeding amount and amylase activity), and chemical composition (inorganic components, chlorophyll contents, cell wall components, amino acids and esterase isozymes) of leaf- sheath and/or roots of rice plants. In conclusion, the natures of varietal resistance of rice cultivars to the BPH were not only correlated with the resistant reaction of rice plant, but also they were related with the non preference in feeding and oviposition and those resistant cultivars had the antibiotic effects to the insects. Their antibiotic effects of rice cultivars to the BPH would be related with some of the chemical components of rice plants, such as the contents of magnesium oxide (MgO), and chlorophyll and the different esterase isozymes.

• Korean Journal of Plant Resources
• /
• v.25 no.1
• /
• pp.132-141
• /
• 2012

This study was carried out to test seed germination responses to temperatures and pre-treatments in Hippophae rhamnoides, which has many abilities in antioxidant activity, soil improvement and erosion control. H. rhamnoides seeds were placed at 10, 15, 20, 25, 30 and $35^{\circ}C$ under light condition. As the results, germination percentage (GP) was the highest at 15 and $20^{\circ}C$, and mean germination time (MGT), germination rate (GR) and germination value (GV) were the highest at $25^{\circ}C$. Quadratic and linear regression model were used to determine the cardinal temperatures such as base ($T_b$), maximum ($T_m$) and optimum ($T_o$) temperature for germination. In quadratic regression model using PG, $T_b$, $T_m$ and $T_o$ was estimated as 0.6, 36.4 and $18.5^{\circ}C$, respectively, and temperature range for germination was $35.8^{\circ}C$. In linear regression model using GR, $T_b$, $T_m$ and $T_o$ was estimated as 8.3, 35.4 and $25.3^{\circ}C$, respectively, and temperature range for germination was $27.2^{\circ}C$. Germination properties were investigated after H. rhamnoides seeds were treated by prechilling (1, 2, 4, 6 and 8 weeks), stratification (2, 4, 6 and 8 weeks), solid matrix priming (seed : carrier : water = 5 : 1 : 7, 8, 9 and 10), osmo-priming (-0.25, -0.5, -1.0 and -1.5 MPa) and calcium chloride ($CaCl_2$) -priming (100, 200, 300 and 400 mM). The highest GP was observed in $CaCl_2$ 300 and 400 mM treatments, and MGT was the shortest in stratification 6 and 8 weeks treatments. GR and GV were the highest and GP was the second highest when seeds were prechilled for 1 and 2 weeks. Consequently, prechilling 1 or 2 weeks treatment was considered as the appropriate method when we contemplate qualitative and quantitative effects in seedling production.

• Korean Journal of Plant Resources
• /
• v.27 no.1
• /
• pp.80-88
• /
• 2014

This study was carried out to understand the effect of sowing date on growth characteristics, flower duration of a total of 6 domestic rapeseed cultivars, "Sunmang", "Tammiyuchae", "Tamlayuchae", "Naehanyuchae", "Yongsanyuchae" and "Hallayuchae" with different sowing dates (25 Sept., 5 Oct., 15 Oct., 25 Oct., 5 Nov.) in Muan, Jeollanamdo, Republic of Korea. The results obtained were summarized as the follows: The number of seedling stand after overwintering was decreased in all 6 cultivars. It changed little until 5 Oct., and then showed continuously largely decrease as the sowing date being delayed. As the sowing date was being delayed, plant height was decreased while Silique length and thousand seed weight were increased. Seed yield in all 6 cultivars decreased almost linearly with late sowing date. In correlation analysis between the delaying sowing date and growth characteristics, it was inversely correlated with plant height ($r=-0.769^{**}$), No. of branches/plant ($r=-0.760^{**}$), No. of siliqua/panicle ($r=-0.631^{**}$) and seed yield ($r=-0.946^{**}$), while showed a positive correlation with silique length (r=0.635), seed diameter ($r=0.629^{**}$) and thousand grain weight ($r=0.422^*$). No. of seeds/silique and seed set percentage were not significantly correlated with the delaying sowing date. The flower duration was long in order of Sunmang, Tammiyuchae, Yongsanyuchae, Naehanyuchae, Hallayuchae and Tamlayuchae. Varietal variation of flowering date was larger with early sowing date than with delaying sowing date. The range of flower duration across all cultivars was from 1 day of Tamlayuchae to 14 days of Sunmang according to the sowing date, and the end flowering date was able to be extended from 2 to 9 days, compared to normal date of end flowering.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.18 no.4
• /
• pp.327-336
• /
• 2016

The Bagan, the central part of Myanmar, is dry zone where the mean annual precipitation is less than 600 mm for the last ten years. Forest in this region has been degraded due to biotic and abiotic disturbances. While there have been various efforts to rehabilitate the degraded area, the information on growth and physiological characteristics of planting species and the impacts of planting trees in the region still lacks. Therefore, this study was conducted to determine the growth and physiological water use efficiency characteristics of five species (Azadirachta indica A. Juss., Acacia catechu Willd., Eucalyptus camaldulensis Dehn., Acacia leucophloea (Roxb.) Willd. and Albizia lebbek (L.) Willd.) which are utilized as rehabilitation species in the dry zone and to identify the impacts of tree planting on microclimate change in dry zone. The growth and the foliar carbon isotope composition of seedlings and the above mentioned five species planted in 2005 were measured. And from February 2015 to January 2016, microclimatic factors air temperature and relative humidity at 60 cm and 2 m above soil, soil temperature, soil water contents and precipitation were measured at every 30-minute interval from the two weather stations installed in the plantation located in Ngalinpoke Mt. Range. One was established in the center of A. indica plantation, and the other was in the barren land fully exposed to the sunlight. Among the five species, A. indica and A. lebbek which showed higher water use efficiency could be recommended as rehabilitation species in dry zone. Planting trees in the dry area was shown to affect the change of microclimate with shading effects, declining temperature of the land surface and aridity of the air, and to contribute to conserving more water in soil by preventing direct evaporation and containing more water with fine roots of trees.

• The Korean Journal of Ecology
• /
• v.26 no.1
• /
• pp.5-12
• /
• 2003

Seed germination rate and seedling growth were measured on 6 different species(Phytolacca americana, Eupatorium rugosum, Rumex acetocella, Echinochloa crusgalli, Cassia mimosoides var. nomame, Setaria viridis) treated with leaf extract of E. rugosum. Total phenolic compound and heavy metal were analyzed on leaf and soil with and without E. rugosum. The growth of P. americana seedlings were stimulated by 10% and 25% of E. rugosum water extract treatment. The content of total phenolic compounds in soil was lower than that of leaf extract, and 25% was confirmed as threshold concentration in natural systems because the total phenolic compounds were not significantly different between the control soils and the soil treated with 10%, and 25% extract. Total phenolic compound concentrations of the leaf extracts were highest (1.66 mg/l) with E. rugosum grown under the Quercus forest canopy and lowest (1.09 mg/l) for the plant grown in the mixed forest edge. Leaf extracts of plants selected in different sampling sites (Forest interior, Forest edge, under Pinus Canopy and Quercus Canopy) were significant, while soil extracts were not. Seed germination of R. acetocella and S. viridis were significantly inhibited at over 50% concentrations of E. rugosum, but C. mimosoides var. nomame was not affected at any concentration. The radicle and shoot growth of the native species group were reduced two times more than those of the exotic species group by the treatment of extracts. Especially, the seed germination percentage and dry weight of E. rugosum were greater than those of the control group by treatments with extracts of 10% and 25%. Analysis of aqueous extracts from E. rugosum by HPLC identified 6 phenolic compounds: caffeic acid (460.9 mg/l), benzoic acid (109.7 mg/l), protocatechuic acid (7.3 mg/l), ρ-hydroquinone (6.0 mg/l), cinnamic acid (2.7 mg/l) and hydroquinone (0.23 mg/l). The seed germination of P. americana was also inhibited dramatically by protocatechuic acid and cinnamic acid even though the content of caffeic acid (460.9 mg/l) was the highest among analyzed phenolic compounds. The heavy metal content of soil without A. altissima was higher than that of soil with E. rugosum. Particularly, Al, Fe and Mn was considerably high and most of the heavy metal were accumulated in leaves where a high level of total phenolic compounds was found.

• Journal of Korean Society of Forest Science
• /
• v.98 no.1
• /
• pp.94-105
• /
• 2009

Black locust (Robinia pseudoacacia) stand is representative lowland exotic plantation with low ecological quality and arrested succession in South Korea. To facilitate succession and restore natural vegetation, small canopy gaps (${\sim}57m^2$), which can modify minimally structural variables and reduce restoration related disturbances on stand, was established in the black locust stand, and oak (Quercus serrata) seedlings were introduced in the gap. Two types of varying levels were introduced for gap creation; cutting (C) and girdling (G) on canopies. Understory removal (CU and GU) treatment was applied as subtypes of structural modification. Growth (diameter, height and leaf area) of target species and responses (species composition, diversity and coverage) of understory community were monitored during study years (2007~2008). Canopy openness was different significantly among treatments but not for light availability. Based on the result of logistic regression, growth of height and leaf area of seedlings were significant variables on seedling survival. Height and leaf area of seedlings were increased during study years, although radial growth was reduced. During study years, there were no significant differences in species composition and diversity, and total coverage increased about 20%. Increase of resources by gap creation and understory removal likely affect growth of target species. Small gap creation was effective to reduce understory responses in composition and diverstiy. Synthesized, growth of target species and responses of understory community to small canopy gap creation exhibited, in short term, possibility of utilization in alternative forest restoration and management option. Long-term monitoring is necessary to certificate effect of artificial gap creation on forest restoration.

• Journal of Korean Society of Forest Science
• /
• v.103 no.1
• /
• pp.65-71
• /
• 2014

Cacalia firma is a perennial plant in Asteraceae, Parasenecio that distributed in Korea, China, and Japan. As dietary style changes for well-being life, consumer's demand of functional food and organic vegetables is getting increased. This study was conducted to investigate the optimum light conditions of P. firmus in forest farming. One year old seedlings were grown under four different light conditions 10%, 20%, 30%, and 50% of sunlight by shading (equals 50%, 30%, 20%, and 10% relative brightness respectively) and non-treated control under full sunlight. They were analyzed for early growth and physiological response. Seedlings grown under 75% shading showed similar height, root growth, and leaf water content to control. However, their leaf length, width, and total leaf area were increased, which caused increased leaf dry weight and total dry weight. Especially, seedlings under 95% shading showed 40% increase in height and more leaf growth and leaf water content, although they had shorter main root length and root collar diameter than control. In addition specific leaf area (SLA) and leaf area ratio (LAR) were higher than control and indicated that they were statistically significant difference from control. Higher SLA refers thinner leaf thickness, higher LAR means larger leaf area. The results indicate seedlings under 95% shading have higher water content, thinner leaf, and wider lightinterception areas. It is plausible that P. firmus is active in chlorophyll activities and carbon dioxide assimilation at even lower light conditions. These results suggest that the optimum light level of P. firmus for artificial cultivation in forest farming ranges from 75~95% shading (20%-10% of relative brightness). When salability as 'sanchae' (wild edible greens) is considered, P. firmus could be cultivated under 75% shading in forest farming and expected to have better taste and higher yield. We suggest these results as basic data of P. firmus for possible forest farming.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.40 no.3
• /
• pp.69-80
• /
• 2012

The purpose of this paper was to study the issues related to converting the graveyards within forests into spaces intended for tree burials by means of planting, given the situation that the graveyards have encroached on land and damaged the environment. For the reason, a field survey was performed to determine the width, length, and distance to the nearest tree of 205 graveyards in the capital area. Through this, it was determined that the domestic lands damaged by graveyards amounted to $862km^2$, including the areas that were deforested to manage the graves. This only confirms that land encroachment by graveyards is a serious issue. The methods for making tree burial sites were examined from the perspective of how to meet public demands given the graveyard's spatial distinctiveness. As a result, this study suggested different methods to establish tree burial sites according to the degree of transformation and the term of its formation. This study also classified the graveyards into three types, and identified the planting methods that harmonized the safe growth of trees and the scenic beauty of memorial places based on the standard. This is in order to plant trees that are shade-tolerant and suitable to the forest line, along with which other tree line was and also, to plant aesthetic trees around the empty space. Through applying the developed methods, this study established and monitored two exemplary sites in Yongin and Boryeng. Aesthetic trees were planted in Yongin site which was located in an open area, aod the shade-tolerant trees were planted in Boryeong, which was located in a forest area. As a result, the image of a garden appeared at Yongin site and the image of a tree colony harmonized with the near forest emerged at Boryeong site. Therefore, it is confirmed that the method of planting according to the distribution status of neighboring trees was effective. As a result of monitoring, mulching wood chips were suitable for sites that were small or easy to approach. This is because the weeds were controlled in Yongin site by mulching. Furthermore, by monitoring the growth of 11 species of vegetation, this study confirmed that low and cover-type vegetations were suitable for tree burial sites. In Boryeong site, the wild cherry trees, which were planted as adult trees, all died, and the tilling of snake's beard, which were planted as cover vegetation, was slow. Therefore, this study found that seedlings were more suitable to plant in forest graveyards than adult trees, which were large and difficult to approach, and it was effective to use the remaining lawn and form a low vegetation after the crown of trees had expanded to such places.

• Korean Journal of Plant Tissue Culture
• /
• v.25 no.4
• /
• pp.257-261
• /
• 1998

The repeated subcultures of in vitro plant materials in wasabi became highly vitrified and the capacity for multiple shoot formation from the vitrified plant materials was very low. In order to improve the quality of in vitro propagated planting materials, the experiments were carried out using culture vessels capped with membrane filter(MF). When vitrified shoots were cultured on MS medium with 0.2mg/L BA in the vessels with MF or without MF for 60 days, the shoots in the vessels with MF did not vitrified. In contrast, the shoots grown in the vessels without MF vitrified at 65%. The stomates of vitrified leaves were circular and inflated, whereas those of normal leaves acclimatizated in the vessels with MF were ovate in shape. The hardened shoots were also cultured on MS media without sucrose containing 0.01mg/L IBA in vessels with(photoautotrophic culture) or without(control) MF. Sucrose was necessary for survival of the in vitro plantlets in the vessels without MF. After 20 days of culture, the shoots in the vessels without MF on the sucrose-free media turned yellow and died. But the shoots in the vessels with MF in the sucrose-free media produced a lot of roots. When shoots were cultured on MS medium with 2% sucrose containing 0.01mg/L IBA in the vessels with(photomixotrophic culture) or without(heterotrophic culture) MF, best growth occured in photomixotrophic culture.

• Journal of Life Science
• /
• v.13 no.4
• /
• pp.433-440
• /
• 2003

Osmotic and solid matrix priming treatments enhanced germination performance. We compared osmotic with solid matrix priming to determine the more effective treatment for improving seed germination in pepper and tomato. Seed hydration was immediately observed after osmotic priming and solid matrix priming treatment. The moisture content of solid matrix primed seeds was lower than that of osmotic primed seeds in the two vegetable crops. Osmotic priming and solid matrix priming did not increased percent germination, but showed shorter number of days to 50% of the final germination percentage ($T_{50}$) compared with untreated seeds, regardless of germination temperature. $T_{50}$ value was reduced in osmotic or solid matrix primed pepper seeds about 6.0, 5.0, 4.6 and 4.0 days compared with untreated seeds at 15, 20, 25, and $30^{\circ}C$, respectively. While, that in tomato seeds was reduced about 3.3, 5.0, 4.6 and 4.0 days compared with untreated seeds at 15, 20, 25, and $30^{\circ}C$, respectively. The effectiveness of osmotic priming or solid matrix priming in reducing the $T_{50}$ was greater when the seeds were germinated at $15^{\circ}C$ than at temperature of higher than $20^{\circ}C$. Solid matrix primed seeds germinated faster than osmotic primed seeds at all temperature in pepper. However, there was no significant difference on the percentage germination between solid matrix and osmotic primed seeds in tomato. After priming, dried-bark seeds showed faster germination than surface-dried seeds in pepper. On the other hand, there was no significant difference in tomato. Emergence of pepper and tomato seeds was markedly enhanced by osmotic priming or SMP treatment although the final emergence percentage was not significantly influenced. On the other hand, early growth was not significantly influenced by osmotic priming or SMP treatment of pepper and tomato seeds.