• Journal of Ecology and Environment
• /
• v.32 no.2
• /
• pp.87-96
• /
• 2009

Pinus thunbergii plantations in Pohang-si, Gyeongsangbuk-do, Korea, are of low ecological quality, with arrested succession and a high proportion of ruderal species. To improve the quality of the habitat, we created canopy gaps ($\sim42\;m^2$) and monitored changes in abiotic (light availability, canopy openness) and biotic (survival and growth of seedlings and understory communities) variables in 2007 and 2008 in plots that had received one of five types of treatment: cutting of canopy trees and removal of the understory (CU), cutting of canopy trees only (C), girdling of canopy trees and removal of the understory (GU), girdling of canopy trees (G) or control. Each treatment was applied to three replicate plots. Abiotic variables did not significantly differ among treatments. Survival rates of target species were slightly lower in the CU, G and control conditions. Based on logistic regression analysis, the only significant growth factor affecting survival was height growth. Positive effects of seedling height and leaf area growth on survival were also detected, but did not reach statistical significance. In treatment G, gradual improvement of overstory conditions and mitigation of competition by limitation of disturbance to the understory community were likely to have promoted seedling growth. There were no significant effects of gap treatments on changes in species abundance (cover and richness) and composition of understory between the study years. This result implies that the small gaps created in our study may be below the threshold size to affect understory growth. However, the results of this study are based on a short-term investigation of only two years. Long-term research is strongly recommended to clarify the effects of gap treatment on plant communities in afforested areas.

• Journal of Ecology and Environment
• /
• v.31 no.4
• /
• pp.341-344
• /
• 2008

We investigated the responses of red squirrels to pine nuts (Pinus koraiensis) treated with Lithium Chloride (LiCl) and the potential of the chemical for inducing conditioned taste aversion (CTA) in red squirrels. In red squirrels, nut feeding declined dramatically during the first 4 days after feeding with LiCl-treated nuts. The ratio of LiCl-treated nuts eaten to total nuts eaten declined from the $1^{st}$ day in LC-1 and the $2^{nd}$ day in LC-2, along with a general reduction in quantity eaten. Thus, feeding with LiCl-treated nuts induced CTA from the 2nd day after feeding, and CTA remained constant until the $4^{th}$ day, but disappeared on the $5^{th}$ day. The squirrels ate an average of $757.0{\pm}106.1mg$ (n = 2, range $682.0\sim832.0$) of LiCl before dying on the $16^{th}$ day of the study. The lethal dose of LiCl was 2.32 mg LiCl/g body weight, and the average amount of LiCl needed to induce CTA was $23.0{\pm}4.24mg$ (20 mg in LC-1 and 26 mg in LC-2).

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.3
• /
• pp.239-245
• /
• 1989

This experiment was conducted to study the physiological and ecological responses of agronomic characters related to source and sink relation in rice. Standard deviation and coefficient of variability of agronomic characters by individual tiller were greatly influenced by the lower internodes in the length of internode, flag leaf in the leaf blade, lower leaf blade in the leaf width, and the number and spikelets of secondary rachis branch in panicle. In relation to the parts of source and sink of rice plant and the number of spikelet in panicle, the number of spikelet was significantly correlated with the length and leaf area of second leaf blade, the length of second internode, and culm diameter of third internode. The correlation of the length of panicle with the length of internode and leaf blade was greatly influenced by the length of second leaf blade and second internode. The number of spikelet was increased with increasing the second rachis branch rather than first rachis branch. The content of total inorganic nutrients was greatest at leaf blade followed by leaf sheath and internode, and panicle.

• Korean Journal of Environmental Biology
• /
• v.34 no.3
• /
• pp.161-168
• /
• 2016

In this study, growth enhancing effect of hatchery waste egg decomposed liquid fertilizer in pepper plant cultivation through chlorophyll fluorescence (O-J-I-P) analysis. In a whole growth period, egg decomposed fertilizer treated pepper grew well than non treated plant, though it was not statistically significantly different. Amount of chlorophyll fluorescence of non treated plant was higher thant that of fertilizer treated plant. It is determined that eventually lead to increased photosynthesis. In this study, six parameters, Fo, ABS/RC, RC/ABS, TRo/RC, DI0/RC, and DF Total ABS were the important factors represent efficiency of photochemical responses of pepper plant treated with hatchery waste egg decomposed fertilizer.

• Journal of the Korean Home Economics Association
• /
• v.42 no.9
• /
• pp.111-134
• /
• 2004

The purpose of this dissertation is firstly to examine the level of pro-environmental behavior of urban employed wives depending on their life style type and secondly to identify effective ways to promote their pro-environmental behavior. A structured questionnaire interview was conducted with 700 urban employed wives who lived in the Seoul Metropolitan area, and 566 of the responses were valid for analysis. For statistical analysis, this research reviewed the frequencies, percentage, mean, standard deviation(SD), Pearson's correlations, Cronbach's u, factor analysis, cluster analysis, ANOVA, $\chi$$^2$-test, Duncan's Multiple Range Test, and multiple regression using SPSS/PC WIN. The findings of analysis of the study are as follows: 1. Among life style types of employed wives, the order of ecological value was orientation type (37.3%), followed by economical value orientation type (25.8%), uninterested type (18.7%), and convenience-centric value orientation type (18.2%).Pro-environmental behavior scored relatively highly at 3.45 in average. 2. In the analysis of the relationship between life style and background variations, every variation except environmental knowledge was meaningful. 3. In the relationship between pro-environment behavior and background variations, every variation was meaningful except housing types, having helper or not, and environmental knowledge. 4. The recognition level of environmental pollution was important among the variations affecting pro-environmental behavior. 5. There was a difference in pro-environmental behaviors by the following life style types: ecological value orientation, economical value orientation, convenience centric orientation and uninterested. 6. For the relative contribution comparison of background variations (socio-economic variation and environmental variation) and life style variations to the pro-environmental behavior of urban empolyed wives, this research additionally applied each independent variable group. As a result, the explanation level drastically increased in the third step that analyzed the relationship with life style.

• Ocean and Polar Research
• /
• v.45 no.2
• /
• pp.57-69
• /
• 2023

Growth responses along the gradient of water temperature, salinity, and light intensity and cytotoxicity against Artemia nauplii were explored using Ostreopsis sp. and Coolia canariensis strains, representing the two potentially toxic epiphytic dinoflagellate (EPD) species from Jeju coastal waters of Korea. Variation in maximum growth rate (GRmax) and maximum biomass yield (Ymax) along the environmental gradients was quite contrasting between the two strains, which appears to be reflected in the in situ abundance distribution of the corresponding genera. The more eurythermal characteristics of Ostreopsis sp. strain were in good agreement with the relative distribution of Ostreopsis spp. and Coolia spp. in 520 macroalgal samples collected from 6 stations. The more stenohaline C. canariensis strain was well matched by a markedly narrower range of salinities in the in situ distribution of Coolia spp. than the salinity range for Ostreopsis species. The differences in light adaptation between the high light-preferring Ostreopsis sp. strain and the more euryphotic C. canariensis strain were remarkably consistent with the distinct vertical profiles of Ostreopsis spp. and Coolia spp. abundance in the red alga Amphiroa sp. off Moom-seom. Cytotoxicity against Artemia nauplii in the Ostreopsis sp. preparation with 1000 cells ml^-1 was similar to that in C. canariensis preparation with 12000 cells ml^-1, which is noteworthy. Thus, the new potential cytotoxicity risks from C. canariensis along with the well-known toxic genus Ostreopsis may be introduced to Jeju coasts, which necessitates further exploration into the contrasting ecological niches occupied by EPD species in relation to their cytotoxicity.

• Journal of Korean Society of Forest Science
• /
• v.107 no.4
• /
• pp.351-360
• /
• 2018

This study was conducted to analyze the responses of chlorophyll contents and growth of Pinus densiflora and Quercus variabilis seedlings on distance from the well and $CO_2$ flux after the artificial $CO_2$ release. From June 1 to 30, 2016, $CO_2$ gas was injected at the rate of $6L\;min^{-1}$ at the study site in Eumseong. Chlorophyll content was analyzed in the middle of July, 2016, and root collar diameter (RCD), height (H), and biomass were measured in May and December, 2016 after planting 2-year-old P. densiflora and 1-year-old Q. variabilis seedlings in May, 2015. The chlorophyll content of P. densiflora seedlings did not show a significant correlation with $CO_2$ flux, whereas the chlorophyll content of Q. variabilis seedlings showed a significant negative correlation with increasing $CO_2$ flux (P<0.05). The RCD and H growth rates of both species showed the significant difference in the distance from the well of the $CO_2$ anthropogenic release treatment. In particular, the RCD and H growth rate of P. densiflora seedlings and the RCD growth rate of Q. variabilis seedlings increased significantly as the seedlings were closer to the well, but the H growth rate of Q. variabilis seedlings decreased significantly. In addition, as the $CO_2$ concentration in the ground increases, ${\Delta}R/S$ ratio increases in both species, suggesting that the high $CO_2$ concentration in the soil promotes carbon distribution relative to the root part. The results of this study can be used as data necessary to monitor the $CO_2$ leakage and physiological and growth responses of both species to leakage of stored $CO_2$ in the future.

• Journal of Ecology and Environment
• /
• v.42 no.1
• /
• pp.1-11
• /
• 2018

Background: In the study, the effects of elevated $CO_2$ and temperature on the nitrogen content, carbon content, and C:N ratio of seven rare and endangered species (Quercus gilva, Hibiscus hambo, Paliurus ramosissimus, Cicuta virosa, Bupleurum latissimum, Viola raddeana, and Iris dichotoma) were examined under control (ambient $CO_2$ + ambient temperature) and treatment (elevated $CO_2$ + elevated temperature) for 3 years (May 2008 and June 2011). Results: Elevated $CO_2$ concentration and temperature result in a decline in leaf nitrogen content for three woody species in May 2009 and June 2011, while four herb species showed different responses to each other. The nitrogen content of B. latissimum and I. dichotoma decreased under treatment in either 2009 and 2011. The leaf nitrogen content of C. virosa and V. raddeana was not significantly affected by elevated $CO_2$ and temperature in 2009, but that of C. virosa increased and that V. raddeana decreased under the treatment in 2011. In 2009, it was found that there was no difference in carbon content in the leaves of the six species except for that of P. ramosissimus. On the other hand, while there was no difference in carbon content in the leaves of Q. gilva in the control and treatment in 2011, carbon content in the leaves of the remaining six species increased due to the rise of $CO_2$ concentration and temperature. The C:N ratio in the leaf of C. virosa grown in the treatment was lower in both 2009 and 2011 than that in the control. The C:N ratio in the leaf of V. raddeana decreased by 16.4% from the previous year, but increased by 28.9% in 2011. For the other five species, C:N ratios increased both in 2009 and 2011. In 2009 and 2011, chlorophyll contents in the leaves of Q. gilva and H. hamabo were higher in the treatment than those in the control. In the case of P. ramosissimus, the ratio was higher in the treatment than that in the control in 2009, but in 2011, the result was the opposite. Among four herb species, the chlorophyll contents in the leaves of C. virosa, V. raddeana, and I. dichotoma did not show any difference between gradients in 2009, but decreased due to the rise of $CO_2$ concentration and temperature in 2011. Leaf nitrogen and carbon contents, C:N ratio, and chlorophyll contents in the leaves of seven rare and endangered species of plant were found to be influenced by the rise and duration of $CO_2$ concentration and temperature, species, and interaction among those factors. Conclusions: The findings above seem to show that long-term rise of $CO_2$ concentration, and temperature causes changes in physiological responses of rare and endangered species of plant and the responses may be species-specific. In particular, woody species seem to be more sensitive to the rise of $CO_2$ concentration and temperature than herb species.

• Journal of Ecology and Environment
• /
• v.42 no.4
• /
• pp.174-182
• /
• 2018

Background: In this study, we observed their growth and physiological responses using a variety of duty ratio under the mixed light using red, blue, and white lights. The red+blue mixed light was treated with 95%, 90%, 85%, 80%, and 75% duty ratios and red+blue+white mixed light with 85% and 70% duty ratios. We examined the width and length of leaves, total number of leaves, and number of shoots to examine their growth responses. The physiological responses were studied by measuring their photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, chlorophyll content, and fluorescence ($F_o$, $F_m$, and $F_v/F_m$). Results: We found that lower duty ratio caused the length and width of the leaves to grow longer under red+blue mixed light but that it did not cause any difference in the red+blue+white mixed light condition. In addition, there was no difference in the number of leaves and shoots among all treatments. In the red+blue mixed light condition, the photosynthetic rate was no difference, but both transpiration rate and stomatal conductance were the highest at 95% duty ratio than in other ratios. Water use efficiency pattern was similar to that of photosynthetic rate; water use efficiency was no difference. Chlorophyll content was the highest at 95% duty ratios, and it was the least at 90%, 85%, and 75% duty ratio. $F_o$ and $F_m$ values were relatively high at 85% and 80% duty ratio and low at 90% duty ratio while $F_v/F_m$ showed no difference. Conclusions: Under the red+blue+white mixed light, all physiological items showed no difference between 70 and 85% treatments. But, photosynthetic rate, water use efficiency, chlorophyll content, and $F_v/F_m$ were relatively greater in the red+blue+white mixed light than in the red+blue mixed light. Therefore, red+blue+white mixed light treated with 70% duty ratio could lessen the environmental stress and save more power when cultivating Silene capitata in a plant factory.

• Journal of Ecology and Environment
• /
• v.36 no.4
• /
• pp.255-265
• /
• 2013

This study was conducted to determine the extent of drought resistance based on physiological responses of Calystegia soldanella under water deficit. In order to investigate the changes of plant growth, stomatal density, photosynthesis, chlorophyll fluorescence, the contents of chlorophyll and carotenoid, osmolality, total ion contents, the contents of carbohydrate and proline, C. soldanella was grown under well watered and drought stressed conditions for 12 days. In this study, water-deficit resulted in remarkable growth inhibition of C. soldanella. The effect of water-deficit on plant growth was associated with low osmotic potential of soil. On day 12 after drought treatment, dry weight, relative water contents, number and area of leaves and stem length were lower than those of control. The stomatal conductance and net photosynthetic rate were significantly reduced in water stressed plant to regulate inner water contents and $CO_2$ exchange through the stomatal pore. Chlorophyll fluorescence and chlorophyll contents were not different in comparison with the control, indicating that the efficiency of photosystem II was not affected by drought stress. This results could be explained that water-deficit in C. soldanella limits the photosynthetic rate and reduces the plant's ability to convert energy to biomass. A significant increase in total ion contents and osmolality was observed on day 7 and day 12. Accumulation of proline in leaves is associated with the osmotic adjustment in C. soldanella to soil water-deficit. Consequently, this increase in osmolality in water stressed plant can be a result in the increase of ion contents and proline.