• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.2
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• pp.79-89
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• 2012

This study was conducted to investigate the chlorophyll contents, photosynthetic characteristics, chlorophyll fluorescence, and growth performance of Parasenecio firmus under changing light environment. Parasenecio firmus was grown under non-treated (full sunlight) and three different shading conditions (88~93%, 65~75% and 45%~55% of full sunlight) for the experiment. Total chlorophyll content, photochemical efficiency (Fv/Fm), T/R ratio, specific leaf area (SLA), leaf area ratio (LAR), and leaf weight ratio (LWR) were increased with increasing shading level, but decreased dark respiration. Therefore, light absorption and light utilization efficiency were improved under the low intensity light. Plants under 65~75% of full sunlight had best maximum photosynthetic rate and net apparent quantum yield in May. On the other hand, the non-treated plants had lower maximum photosynthetic rate, photochemical efficiency, and chlorophyll content than the treated ones. Parasenecio firmus considered to be a sciophyte, is fairly sensitive to high intensity light. If 88-93% of full sunlight lasts for a long period, photosynthetic capacity will be sharply decreased, though limiting light. These results suggest that growth of Parasenecio firmus adapted to 65~75% of full sunlight.

• Journal of Bio-Environment Control
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• v.19 no.2
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• pp.97-108
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• 2010

The present study was conducted to investigate photosynthetic responses (Pn), chlorophyll fluorescence (Pe), chlorophyll contents of Allium victorialis var. platyphyllum, Ligularia fischeri, and Ligularia stenocephala growing at four different fertilizing schemes (non-fertilizing and 2.5 $g{\cdot}l^{-1}$, 5 $g{\cdot}l^{-1}$, 10 $g{\cdot}l^{-1}$ fertilizing). Three wild vegetables showed outstanding Pn and Pe at 5 $g{\cdot}l^{-1}$ fertilizing treatment. 10 $g{\cdot}l^{-1}$ of fertilizer, however, proved to be too much eventually leading to declined growth. A. victorialis var. platyphyllum showed good Pn and Pe under shade treatment whereas Pn and Pe of L. fischeri, and L. stenocephala showed the opposite tendency. The chlorophyll contents of the three wild vegetables showed the highest measurement ranging between 11.70~24.36 $mg{\cdot}g^{-1}$ when treated with 5 $g{\cdot}l^{-1}$ of fertilizer. Also it was showed that there were more chlorophyll contents under shade treatment as opposed to full sun. These results showed that 5 $g{\cdot}l^{-1}$ fertilizing treatment is optimal fertilizing of three wild vegetables and fertilizing and light intensity controlling is very important for productivity of vegetables.

• The Korean Journal of Ecology
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• v.21 no.3
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• pp.187-193
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• 1998

Seasonal changes of nitrogen fixation and growth characteristics of Melilotus suaveolens population under different light conditions were quantitatively analyzed during growting period. Height growth of M. suaveolens population was promoted after April and the shade (site 2) showed 10-20% increase of height growth in compared with that of sunny (site 1). Seasonal changes of biomass were in creased after March, the biomass at site 1 attained 78.5% that of site 2 in May. Chlorophyll content was maintained high value from March to April but, Chlorophyll content of leaf at site 1 was decreased 11.7% compared to that of site 2 in May. The nitrogen content of each organ of M. suaveolens showed higher value in March and then decreased, the high nitrogen contents of reproductive organ were achieved at the flowering stage at site 1. The root nodule of M. suaveolens population appeared in March and showed maximum value in early June and decreased remarkably after July, the amount of nodule formation of M. suaveolens at site 2 showed higher than that of site 1. The nitrogen fixation activity of root nodule of M. suaveolens initiated with shoot growth and showed maximum value in mid April, and attained second peak in early June and then decreased after July. The total nitrogen fixation of the plant showed higher value at site 2 than that of site 1. From the overall results, M. suaveolens showed increased growth under half-shady, well ventilated barren soil than fertile sunny site.

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.17-23
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• 2000

The spatial distribution of allelic frequencies was studied in the natural population of three species (Ligustrum obtusiflolium, Alnus japonica, and Pinus densflora). The distributional patterns of the crown-cover centers were compared between two populations in forests. L. obtusifolium and p. densiflora showed a significantly positive spatial autocorrelation as measured by Moran's I. In P densiflora, the genetic similarity was shown by individuals within up to a scale of 18 m distance and this is partly due to combination of pollen dispersal and long distance seed dispersal by wind or men. In L. obtusifolium, population structure in the distribution of allelic frequencies is related to mating systems and is consisted of a scale of 12.5 m intervals. No spatial structuring of allele frequencies was found for polymorphic enzyme loci within a natural population of Alnus japonica. The results also in- dicate that positive associations between L. obtusifolium and P densiflora can occur when both select the same habitat or have the same environmental requirements.

• Journal of Korean Society of Forest Science
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• v.76 no.1
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• pp.1-10
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• 1987

This study was carried out to examine the influence of shading and root-cutting on the survival and growth of Pinus koraiensis seedlings. 1, The highest survival percentage of seedlings transplanted to transplanting bed appeared at the plot of 19% in shading. The 50% of the seedlings were survived if half of them were root-cutting. 2. Shoot elongation, root growth and diameter increment were the best at the plot of 100% in relative light intensity. However, those were the best at the plot with 1/4 root cutting. 3. The increase of needle fascicle number and the growth of needle surface area per seedling were the longest at the plot of 63% relative light intensity. Among root cutting treatments the 1/4 cutting plot showed the largest growth of needle areas.

• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.1-8
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• 1997

Second year results are presented from a trial designed to quantify the reduction in radiata pine(Pinus radiata D. Don) seedling growth caused by competition from a range of important weed species on a moist North Island site in New Zealand. Radiates pine seedlings(1/0) were grown on the weed free control and with either herbaceous broadleaves, grass, broom, pampas, buddleia, or gorse. Resource(nutrient and water) levels were varied by factorial +/- irrigation and fertilizer treatments. Radiata pine seedling volume growth 21 months after planting was greatest when it was grown on the weed free control or in association with gorse, and was least when grown with either buddleia or pampas. There was no evidence that the effects of the weeds on seedling growth were mediated by either competition for water or nutrients. Tall, fast-growing species that overtopped the seedlings(broom, buddleia, pampas) had the greatest effect on seedling growth and the magnitude of the effect was correlated with degree of overtopping. This implies that shading or competition for light is probably an important factor.

• Journal of Korea Foresty Energy
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• v.19 no.1
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• pp.20-29
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• 2000

This study was carried out to investigate the effects of shading on the growth of 1 -year-old seedlings of Cornus controversa. The height growth was highest in relative light intensities of 100% and 50%, but relative growth rate in 50% was higher than that in 100% treatment. The growth did not occur under 9% relative light intensity. The root collar diameter growth at different light intensities is similar to height growth. The leaf area was highest in 50% relative light intensity, and the leaf area under the light intensity was small compared with the control. SLA and LAI of seedlings increased with decreasing relative light intensity. The LAR and LWR of seedlings increased with decreasing light intensity, but LWR decreased at 9% relative light intensity. The dry weight of root, stem, leaf and branch, and the number of branch and leaf decreased with decreasing relative light intensity. T/R ratio was highest in 17% and 30% relative light intensity. Lateral root growth decreased with decreasing light intensity except for that in 50% light intensity.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.4
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• pp.141-148
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• 2008

This study was conducted to investigate the photosynthetic responses of four Oak species (Quercus mongolica, Q. serrata, Q. acutissima and Q. variabilis) by shading treatment. We investigated light response curve, photosynthesis (A)-intercellular $CO_2$ concentration (Ci) curve, leaf growth and chlorophyll content at the level of 35, 55 and 75% shading treatments and under the full sunlight. In our results, Q. variabilis and Q. acutissima showed increased leaf growth, chlorophyll content and net apparent quantum yield but reduced chlorophyll a/b and carboxylation efficiency under the low light intensity. Therefore, light absorption and light utilization efficiency were improved under the low light intensity. Q. mongolica showed the similar responses that Q. variabilis and Q. acutissima showed, but net apparent quantum yield was reduced. The effects of shading treatment on Q. serrata were lower than those of other three species.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.82-87
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• 2009

In order to characterize the ecological traits of Quercus acutissima, Q. variabilis and Q. mongolica, which dominated in Korean mountain, we treated the sapling of the three oak species under the major environment factors (light, soil moisture and nutrient) with four gradient levels, for 8 months in glass house. Then we measured and analyzed the growth difference among them. The growth of Q. acutissima and Q. variabilis were increased with higher light intensity, but there is no apparent trend in Q. mongolica for light gradients. Q. mongolica did not show high reduction of growth, even in the lowest light intensity. Q. variabilis and Q. mongolica had a constant growth state to soil moisture treatment, but only Q. acutissima grew well in higher soil moisture gradient condition. All the growth of three oak species decreased with higher nutrient gradient condition. The growth reduction was increased in order of Q. variabilis, Q. mongolica and Q. acutissima. with increased nutrient gradient level. These results means that Q. mongolica, Q. acutissima and Q. variabilis have adaptation ability to shade, high moisture and low nutrient condition, respectively.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.591-597
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• 2000

This studies were carried out to investigate the optimum shading for seedling cultivation of Cornus controversa and C. walteri. The experiment was performed under five different shading scheme such as 100%, 50%, 30%, 10%, and 2% of the natural full sun light intensity for 7 months in the field condition. Two species showed the highest height growth under 50% of relative light intensity, and the highest diameter growth at root collar was observed both under 100% and 50% of relative light intensity. C. controversa seedlings grown under 50% of relative light intensity produced more total biomass than control seedlings, but root biomass was less in the seedlings under 50% of relative light intensity. In case of C. walteri, total biomass production of the seedlings under 50% of relative light intensity was lower than that of the seedlings under full sun light intensity, but leaves and shoot biomass was slightly high under 50% of relative light intensity. Great reductions of height growth and diameter growth at root collar, and biomass production were observed below 30% of relative light intensity in the both species. T/R ratio of the two species was highest under 30% of relative light intensity, and the chlorophyll content of the seedlings tended to be increased by reduction of relative light intensity.