Shading Treatment-Induced Changes with Growth and Physiological Characteristics in Delphinium maackianum Regel

조승주,김동학,윤정원,정은주 한국자원식물학회 2025 한국자원식물학회지 Vol.38 No.3

Delphinium maackianum was grown under different shade treatments to examines the impact of different shading levels on the growth, physiological characteristics. The leaf mass per area (LMA) was lowest in the 95% shading treatment, indicating thinner and broader leaves, however significant differences were not observed across shading levels. Chlorophyll content (a, b, and total) increased with higher shading. Fv/Fm and NPQ values showed no significant differences among treatment groups except for the full light treatment, suggesting maintained photosystem II functionality and photoprotective mechanisms. The dark respiration rate (Rd) and light compensation point (LCP) decreased with increased shading, reflecting shade-tolerant plant responses. The 95% shading treatment exhibited the highest photosynthetic rates, light saturation points (LSP), and apparent quantum yields (AQY), indicating enhanced photosynthetic efficiency under low light conditions. Correlation analysis revealed negative relationships between relative light intensity and several physiological traits, including chlorophyll content, LCP, LSP, maximum photosynthetic rate, and AQY. This indicates that D. maackianum optimizes photosynthesis under low light conditions by increasing light absorption and utilization efficiency. The study underscores the species’ ability to adjust its physiological processes and structural characteristics to thrive in varying shading environments, highlighting its adaptive strategies for survival and growth in shaded habitats.

The Importance of Halogen Bonding: A Tutorial

조승주 조선대학교 기초과학연구원 2012 조선자연과학논문집 Vol.5 No.3

Halogen atoms in a molecule are traditionally considered as electron donors, since they have unshared electrons. Normally when they are bonded, there are three lone pair electrons. These lone pairs can function as Lewis bases. However, when they are bound to electron withdrawing groups, they can act as Lewis acids. Since the situation is similar hydrogen bonding (HB), this type of interaction is named as halogen bonding (XB). This mainly comes from the uneven distribution of electron density around the halogen atoms. Since the electron density around halogen atom opposite to σ-bond is depleted, its electropositive region is called σ-hole. This σ-hole can attract halogen bond acceptors, requiring more stringent directionality compared to HB. Since this interaction mainly comes from electrostatic origin, the geometry tends to be linear. Since the XB energy is comparable to corresponding HB. Still in its infancy, XB shows a broad range of applicability, with potentially more useful properties, compared to corresponding HB.

Theoretical Study of Trioxane Derivatives as Amphi-ionophores: Importance of Charge-Dipolar Moiety Orientation

조승주 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.9

Recently we have reported a novel class of anion receptors which are based on 2n-crown-n topology. Trioxane derivatives are capable of anion sensing through pure aliphatic C-H hydrogen bonding. In this work, we highlight another interesting property, i.e., they can also recognize cations as normal crown ethers (3n-crownn topology). Since the same functional moiety can recognize anions and cations, these coronands are predicted to be amphi-ionophores. However, we could not detect cations even in the gas phase. Considering trioxane is analogous to [16]starand, this was rather counter-intuitive. The calculation results show that these coronands can detect alkali metals with very low affinity. The low affinity toward cations should be responsible for this failure of experimental detection. With careful theoretical study, we found that this low affinity toward cations could be explained by the unfavorable charge-dipolar moiety orientations as proposed by Cui et al. As in the case of [16]starand, this is an example that underscores the importance of charge-dipolar moiety orientation in supramolecular interactions.

소분자 도킹에서 탐색공간의 축소 방법

조승주 조선대학교 기초과학연구원 2010 조선자연과학논문집 Vol.3 No.3

부분 전하의 계산과 응용

조승주 조선대학교 기초과학연구원 2010 조선자연과학논문집 Vol.3 No.4

부분 전하의 의미와 정의

조승주 조선대학교 기초과학연구원 2010 조선자연과학논문집 Vol.3 No.4

생물학적 데이터 분석의 총아

조승주,Jo, Seung-Ju 한국과학기술단체총연합회 2004 과학과 기술 Vol.37 No.11

차광처리가 제비붓꽃의 생장 및 생리적 특성에 미치는 영향

조승주,김동학,정은주,윤정원 한국자원식물학회 2024 한국자원식물학회지 Vol.37 No.2

본 연구에서는 북방계 식물 제비붓꽃의 현지외 보전에 필요한 생육 적정 광조건을 제시하기 위하여 차광처리에 따른 제비붓꽃의 생장과 생리적 반응을 조사하였다. 전천광을 수광하는대조구와 서로 다른 차광처리구(50%, 75%, 95%)를 설치하고 엽면적당 건중량, 엽록소 함량과 형광 반응, 광합성 특성을 조사하였다. 제비붓꽃은 차광수준이 강해질수록 낮은 광도에 적응하기 위하여 광합성 효율이 높아진 잎이 형성되었다. 차광수준이 높아질수록 엽록소 함량이 증가하였고, 엽면적이 증가하면서 엽면적당 건중량은 감소하였다. 차광처리에 의해 엽록소 형광 반응 Fv/Fm과 NPQ는 변화하지 않았고, 탄소고정계의 활성또한 처리 간에 차이가 없었다. 제비붓꽃은 양지식물에 해당하는 광포화점을 나타냈고, 75% 차광수준까지 광합성 능력을 대조구와 비슷한 수준으로 유지하였다. 제비붓꽃의 순양자수율은 95% 차광처리에서 현저히 감소하여 낮은 광조건에 적응한상태를 보였다. 제비붓꽃은 전천광 대비 95% 차광수준에서 생육할 시 광합성 능력이 저하하는 것으로 보이며, 차광 상태를 지속하여 광을 제한할수록 생육이 불리할 것으로 판단된다. Abstract - In this study, we investigated the growth and physiological responses of Iris laevigata Fisch. to shading treatments in order to suggest optimal light conditions for ex-situ conservation of the northern lineage plants. For this purpose, a control plant receiving full sunlight and different shading treatments (50%, 75%, 95%) were installed, and leaf mass per area, chlorophyll content and fluorescence response, and photosynthetic characteristics were investigated. I. laevigata developed leaves with higher photosynthetic efficiency to adapt to lower light intensity as shading levels increased. Chlorophyll content increased with increasing shading levels, and leaf mass per area decreased with increasing leaf area. The chlorophyll fluorescence responses Fv/Fm and NPQ did not change with shading, and the activity of the carbon fixation system did not differ between treatments. I. laevigata exhibited a light-saturation point equivalent to that of sun plants and maintained photosynthetic capacity similar to that of controls up to 75% shading. The apparent quantum yield of I. laevigata decreased significantly at 95% shading, indicating adaptation to lower light conditions. It seems that the photosynthetic capacity of I. laevigata decreases when grown under 95% shading level compared to full sunlight, and it is judged that the longer the light is restricted by continuous shading, the more unfavorable the growth will be.

Docking and Quantum Mechanics-Guided CoMFA Analysis of b-RAF Inhibitors

조승주,M. Muddassar,F. A. Pasha,유경호,이소하 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.8

Pyrazine derivatives bind to b-RAF receptor which is important in cancer therapy. The ligand-receptor interactions have been studied by comparative molecular field analysis (CoMFA) and molecular docking methods. Applying conventional ligand-based alignment schemes for the whole set was not successful. However, QM and DFT results suggested that some ligands have electrostatic interaction while others have steric interactions. On the basis of these results, we divided the dataset into two subsets. Electrostatic effect was found to be important in one set while steric effect for the other. Best docking modes were obtained for each subset based on the available crystal structure. These receptor-guided CoMFA models propose an interesting possibility which is difficult to obtain otherwise. i.e., in one binding mode the electrostatic interaction plays a key role for one subset (q2 = 0.46, r2 = 0.98), while in another binding mode steric effect is important with another subset (q2 = 0.43, r2 = 0.74).

전개형 반사판 안테나의 패널 불완전 전개에 의한 편파특성 영향

조승주,이시아,이택경,이재욱 한국전자파학회 2020 한국전자파학회논문지 Vol.31 No.5

본 논문에서는 전개형 반사판 안테나의 불완전 전개가 안테나의 편파 성능에 미치는 영향에 대해 분석하였다. 포물면의 성질을 이용하는 전개형 반사판 안테나에 불완전 전개가 발생하면 안테나의 형상이 온전한 포물면의 형상을 이루지못하여 안테나의 동일편파 패턴뿐만 아니라, 교차편파 패턴 또한 악화시켰다. 안테나의 불완전 전개가 대칭으로 발생한경우와 비대칭으로 발생한 경우에 대한 안테나 성능 저하의 차이를 조사하였다. 불완전 전개 형상이 대칭인 경우에는교차편파 성능에 미치는 영향이 미약하지만, 비대칭 형상의 경우에는 교차편파가 68 dB 정도 높으며, 교차편파 성능은안테나의 비대칭 형상에 의해 주로 발생하는 것을 확인하였다.