• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.154-161
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• 2013

This study was conducted to investigate the physiological responses of Bupleurum latissimum, endangered plants by light condition. We investigated photosynthetic parameters, chlorophyll contents and chlorophyll fluorescence under different shading treatments (Shaded 50%, 70%, 90% and non-treated). Results showed that net apparent quantum yield (AQY) and chlorophyll contents were significantly increased with elevating shading level. However, light compensation point (LCP) and dark respiration ($R_d$) were shown the opposite trend. Especially, non-treated exhibited photoinhibition such as reduction of chlorophyll contents and maximum photosynthesis rate ($Pn_{max}$) also variation trend of stomatal conductance ($g_s$), and transpiration rate (E) were decreased to prevent water loss. Photosynthetic rate ($P_{Nmax}$) and photochemical efficiency (Fv/Fm) of 90% treatment showed a drastic reduction in July. This implies that photosynthetic activity will be sharply decreased with a long period of low light intensity. The 50% treatment showed relatively higher photosynthetic activity than other treated. This result suggested that growth and physiology of B. latissimum adapted to 50% of full sunlight.

• 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.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.143-150
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• 2009

Deicing salt is used to melt snow and ice on the road for traffic safety during the winter season, which accumulates in the roadside vegetation and induces visible injuries. The damage may accelerate particularly when it coincides with early spring leaf out. In order to better understand the response mechanisms, C. kousa (3-year-old) was irrigated twice prior to leaf bud in a rhizosphere with solutions of 0.5, 1.0, and 3.0% calcium chloride ($CaCl_2$) concentration, that were made by using an industrial $CaCl_2$ reagent practical deicing material in Seoul. Physiological traits of the mature leaves were progressively reduced by $CaCl_2$ treatment, resulting in reductions of total chlorophyll contents, chlorophyll a:b, photosynthetic rate, quantum yield, stomatal conductance, $F_V/F_M$, and NPQ. On the contrary, light compensation point and dark respiration were increased at high $CaCl_2$ concentration. A decrease in intercellular $CO_2$ concentration by stomatal closure first resulted in a reduced photosynthetic rate and then was accompanied by low substance metabolic rates and photochemical damage. Based on the reduction of physiological activities at all treatments ($CaCl_2$ 0.5%, 1.0%, and 3.0%), C. kousa was determined as one of the sensitive species to $CaCl_2$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.3
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• pp.196-207
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• 2019

This study was carried out to investigate the effects of C. japonica, D. morbifera, D. macropodum, I. anisatum, Q. glauca and R. indica To investigate the photosynthetic ability, chlorophyll content, chlorophyll fluorescence analysis, and physiological environmental. The photosynthetic rate, cancer respiration rate, stomatal conductance, and rate of evaporation tended to decrease as a result of drying stress in the no-water condition for 28 days. I. anisatum, Q. glauca and R. indica showed a low rate of less than 40% until 28 days of no-treatment. The total chlorophyll contents were decreased in the order of D. macropodum> D. morbifera> C. japonica> Q. glauca> M. thunbergii> R. indica> I. anisatum. Chlorophyll fluorescence analysis showed that there was no change in the qP, but after 28 days no $Fv/F_m$, $F_o$, $R_{fd}$, $NPQ_{_-LSS}$ can be a useful indicator for quantitative estimation within a short period of time with a marked reduction rate of PSII quantum yield ${\Phi}PSII$ in the rectified state by continuous light during the nominal adaptation period. In the case of I. anisatum, Q. glauca and R. indica If water management can be carried out at intervals, it may be possible to plant trees in trees and landscape trees.

• Journal of IKEEE
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• v.26 no.4
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• pp.736-741
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• 2022

Lattice-based cryptography is the most practical post-quantum cryptography because it enjoys strong worst-case security, relatively efficient implementation, and simplicity. Ring learning with errors (R-LWE) is a public key encryption (PKE) method of lattice-based encryption (LBC), and the most important operation of R-LWE is the modular polynomial multiplication of rings. This paper proposes a method for optimizing modular multipliers based on approximate computing (AC) technology, targeting the medium-security parameter set of the R-LWE cryptosystem. First, as a simple way to implement complex logic, LUT is used to omit some of the approximate multiplication operations, and the 2's complement method is used to calculate the number of bits whose value is 1 when converting the value of the input data to binary. We propose a total of two methods to reduce the number of required adders by minimizing them. The proposed LUT-based modular multiplier reduced both speed and area by 9% compared to the existing R-LWE modular multiplier, and the modular multiplier using the 2's complement method reduced the area by 40% and improved the speed by 2%. appear. Finally, the area of the optimized modular multiplier with both of these methods applied was reduced by up to 43% compared to the previous one, and the speed was reduced by up to 10%.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.4
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• pp.1-13
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• 2022

This study was conducted to investigate the chlorophyll content, photosynthetic characteristics, and growth characteristics of Aster koraiensis and Dendranthema zawadskii var. latiloba according to shading treatment. A. koraiensis and D. zawadskii grew in four different shading treatment plots (0%, 50%, 75% and 95% of full sunlight) for experiments. It was found that as the shading level increased, the total chlorophyll content increased and dark respiration decreased in both A. koraiensis and D. zawadskii, indicating that A. koraiensis and D. zawadskii increase the utilization efficiency for photosynthesis under low light conditions. In addition, as the shading level increased, the net apparent quantum yield increased, resulting in the highest in the 95% shading plot, but the highest photosynthetic rate, water use efficiency, and leaf mass per area (LMA) were shown in the control group than in the shading treatments. The results showed that A. koraiensis and D. zawadskii are heliophytes showing plasticity to light, and if the light is restricted to continue to shade, it may be detrimental to growth. For healthy growth, it is considered suitable to grow A. koraiensis under full light conditions, and D. zawadskii under the light condition that blocks 0-50% of full sunlight.

• Journal of Korean Society of Forest Science
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• v.111 no.3
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• pp.405-417
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• 2022

The purpose of this study was to describe the photosynthetic features of Prunus maximowiczii and Prunus serrulate Lindl. var. pubescens (Makino) Nakai in response to drought stress. Specifically, we studied the effects of drought on photosynthetic ability and photosystem II activity. Drought stress (DS) was induced by cutting the water supply for 30 days. DS decreased the moisture contents in the soil, and between the 10th and 12th days of DS, both species had 10% or less of x., After the 15th day of DS, it was less than 5%, which is a condition for disease to start. We observed a remarkable decrease of maximum photosynthesis rate starting from 10th day of DS; the light compensation point was also remarkable. Dark respiration and net apparent quantum yield decreased significantly on the 15th day of DS, and then increased on the 20th day. In addition, the stomatal transpiration rate of P. maximowiczii decreased significantly on the15th day of DS, and then increased on the 20th day. Water use efficiency increased on the 15th day of DS, and then decreased on the 20th day. The stomatal transpiration rate of P. serrulate decreased significantly on the 20th day of DS, and then increased afterward, while its water use efficiency increased on the 20th day of DS, and then decreased afterward. These results indicate that the closure of stoma prevented water loss, resulting in a temporary increase of water use efficiency. Chlorophyll fluorescence analysis detected remarkable decreases in the functional index (PI_ABS) and energy transfer efficiency in P. maximowiczii after the 15th day of DS. Meanwhile, photosystem II activity decreased in P. serrulate after 20 days of DS. In addition, Ts-Ta, PI_ABS, DI_O/RC, ET_O/RC followed similar trends as those of the soil moisture content and photosynthetic properties, indicating that they can be used as useful variables in predicting DS in trees.