• Journal of Ecology and Environment
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• 제36권4호
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• pp.255-265
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• 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.

• Plant Breeding and Biotechnology
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• 제5권4호
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• pp.363-370
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• 2017

In this study, Quercus acutissima seedlings were subjected to drought for 30 days then analyzed to determine their response to water deficit. The growth phenotype, chlorophyll fluorescence response, fresh weight, dry weight, photosynthetic pigment levels, soluble sugar content, and malondialdehyde (MDA) were measured to evaluate the effects of drought on plant growth and physiology. The growth phenotype was observed by infrared (IR) digital thermal imaging after 30 days of drought treatment. The maximum, average, and minimum temperatures of drought-treated plant leaves were $1-2^{\circ}C$ higher than those of the control. In contrast, the fresh and dry weights of the dehydrated leaves were generally lower than those of the control. There were no significant differences between treatments in terms of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid levels. Nevertheless, for the drought treatment, the $F_v/F_m$ and $F_v/F_o$ ratios (chlorophyll fluorescence response) were lower than those for the control. Therefore, photosynthetic activity was lower in the dehydrated plants than the control. The drought-stressed Q. acutissima S0536 had lower soluble sugar (glucose and fructose) and higher MDA levels than the controls. These findings may explain the early growth and physiological responses of Q. acutissima to dehydration and facilitate the selection of drought-resistant tree families.

• ALGAE
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• 제24권2호
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• pp.93-104
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• 2009

Imaging-PAM fluorometry was used to assess the chlorophyll a fluorescence parameter ${\Phi}_{PSII}$ (effective quantum yield) in Frcus vesiculosus. F. disttchus. ssp. distichus and AscophyIIum nodosum. The objective was to show variadon in fluorescence yield associated with age and frond organ, and to illustrate the spatial scales at which photosynthetic parameters vary on fucoid thalli. In addition, our species represented taxa in different but related genera, species with different ecoloeies (rock pool and non rock pool species), morphologies (with and without air bladders) and longevities (several to 20 or more years). A further objective was to determine the extent to which photosynthetic parameters reflected these differences- Effective quantum yield declined substantially with age in F. vesiculosus and F. distichus ssp. distichus, whereas ${\Phi}_{PSII}$ in A. nodosum was maximal after three years. In A. nodosum ${\Phi}_{PSII}$ was still high in branch segments at least seven years old. Older branches of A. nodosum showed relatively higher and more homogeneous photosynthetic capacity relative to Fucus species. Surfaces of air bladders in A. nodosum and F. vesicu- losus had ${\Phi}_{PSII}$ that was not significantly different from the highest rates, achieved in these species. The heterogene- ity of photosynthetic efficiency is consistent with morphological and developmental differences among the species and their ecology. in particular the longevity of A. nodosum fronds.

• Journal of Photoscience
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• 제9권2호
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• pp.385-387
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• 2002

Direct EPR evidence of the photo-generation of superoxide radicals ( $O_2$$^{-.}$) was obtained by using spin trapping techniques in spinach photosystem II (PSII) membranes. $O_2$$^{-.}$ was detected by following the formation of 5-diethoxyphosphoryl-5-methyl-1 -pyrroline-N-oxide (DEPMPO) superoxide adducts, DEPMPO-OOH. The significant increase of the EPR signal amplitude of DEPMPO-OOH in N$H_2O$H-, CaC $l_2$- and NaCl-treated PSII membranes showed that the oxygen-evolving system has a close relation to the $O_2$$^{-.}$ production. PSII membranes with inactivated donor side could not prevent the $O_2$$^{-.}$ production efficiently. Treatments on PSII donor side also influence the maximum level and the kinetics of Chlorophyll (Chi) a fluorescence. Results suggested that manganese cluster and extrinsic proteins might affect Chi a fluorescence in ways different from that happens at the acceptor side of PSII.SII.SII.

• 한국농림기상학회지
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• 제21권3호
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• pp.196-207
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• 2019

본 연구는 현재 국내에서 조경소재로 이용하고 있는 목본식물 중 동백나무(C. japonica), 황칠나무 (D. morbifera), 굴거리나무(D. macropodum), 붓순나무(I. anisatum), 후박나무(M. thunbergii), 종가시나무(Q. glauca), 다정큼나무(R. indica) 등 7수종에 대해서 건조 스트레스에 따른 광합성 능력, 엽록소 함량, 엽록소 형광분석에 미치는 영향 및 생리적 환경지표를 알아보고자 수행하였다. 28일 동안 무관수 상태에서 건조 스트레스를 유발한 결과 광합성 속도, 암호흡 속도, 기공전도도, 증산속도는 전반적으로 감소하는 경향을 보였으나 I. anisatum, Q. glauca 및 R. indica의 경우 무관 수 처리 28일까지 40% 이하의 낮은 감소율을 보였다(p<0.05). 총 엽록소 함량의 경우 D. macropodum> D. morbifera> C. japonica> Q. glauca> M. thunbergii> R. indica> I. anisatum 순으로 무관수 기간이 길어질수록 유의적으로 감소하는 경향으로 나타났다. 엽록소 형광을 분석한 결과 광화학적 소멸(qP)는 변동이 없는 반면, 무관수 28일 이후 광계II 활성(Fv/Fm), 암적응 형광값(Fo), 형광감소량($R_{fd}$), 정류상태 광화학적 소광($NPQ_{_-LSS}$), 명적응 기간 동안 연속광에 의한 정류상태 PSII양자 수득율 ${\Phi}PSII$에서 뚜렷한 감소율로 짧은 시간 내에 정략적으로 파악하는데 있어 유용한 지표가 될 수 있을 것으로 판단된다. 따라서 내건성이 높게 나타난 I. anisatum, Q. glauca, R. indica의 경우 최대 20일 간격으로 물관리를 할 수 있다면 가로수 및 조경수에 식재하여도 무방할 것으로 판단된다.

• 한국환경농학회지
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• 제34권3호
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• pp.210-216
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• 2015

BACKGROUND: In korea, sweet persimmon(Diospyros kaki) cultivation is front to abiotic stresses such as frost damage at fruit maturing stage. The cold and rapid freezing stresses are most damaging to fruit production which is most actively progressed in late fall. This study was performed to evaluate the validity of chlorophyll fluorescence imaging(CFI) technology to determine the degree of frost damage in sweet persimmon fruits. METHODS AND RESULTS: The sweet persimmon fruits were measured separately for each treatment(15, 30, 60 minutes) at 24 hours after treatment(HAT) rapid freezing. A CFI FluorCam (FC 1000-H, PSI, Czech Republic) was used to measure the fluorescence images of the fruits. In rapid freezing for 15 minutes, photochemical parameters were not changed. However, in rapid freezing for 30 and 60 minutes, photochemical parameters were lowered. Especially, $F_m$, $F_v$, $F_v/F_m$ and ${\Phi}PSII$ values were declined under rapid freezing. CONCLUSION: In our study, it was clearly indicated that the rapid freezing could be a stress in sweet persimmon fruits. The CFI analysis and its related parameters are applicable as a rapid assessing technique for the determination of frost damage.

• 한국환경농학회지
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• 제20권2호
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• pp.93-98
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• 2001

저온에 내성인 자포니카의 일품벼와 감수성인 인디카의 태백벼 품종간에 저온처리기간 동안 및 저온처리 후 회복동안에 나타날 수 있는 생리적 반응을 비교하였다. $5^{\circ}C$의 저온처리 3일 동안에 잎의 생체중 및 엽록소 함량은 두 품종간에 차이가 적거나 없었으나 저온처리 후 $25^{\circ}C$에 회복시킨 동안에는 태백벼에 비해 일품 벼가 더 빨리 회복되었다. 상대적 수분함량, 지질과산화 작용의 지표인 malondialdehyde 생성량 및 엽록소 형광은 저온처리기간 동안 및 저온처리 후 회복기간동안에도 두 품종간에 유의적인 차이를 보였고, 이들 생리적 지표들은 생체중 및 엽록소 함량보다는 더 민감한 생리적 지표이었다. 두 품종간에 상대적 수분함량, malondialdehyde 생성량 및 엽록소 형광의 차이는 저온처리 후 회복기간동안보다는 저온처리동안에서 더 적었다. 따라서 이들 결과를 통해서 볼 때 상대적 수분함량, malondialdehyde 생성량과 엽록소 형광은 저온에 내성을 선발하는데 중요한 생리적 지표로 이용할 수 있으리라 생각한다.

• Journal of Crop Science and Biotechnology
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• 제11권1호
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• pp.75-82
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• 2008

Functional stay-green is a beneficial trait that may increase grain yield through the sustained photosynthetic competence during monocarpic senescence in cereal crops. The temporal changes of photosynthesis and related characteristics throughout the grain filling period of a stay-green japonica rice "SNU-SG1" was compared in growth chamber conditions with three high-yielding cultivars(HYVs) and their $F_1$ hybrids with SNU-SG1. SNU-SG1 exhibited a typical characteristic of functional stay-green in terms of chlorophyll degradation and photosynthetic competence during grain filling. According to the photosynthesis-light response curve measured at 10 and 35 d after heading for the flag leaf, SNU-SG1 exhibited higher initial light conversion efficiency and thus higher gross photosynthetic rate at light saturation compared to HYVs. Light saturation point was not different among genotypes, ranging from 1000 to 1500 ${\mu}mol$ photon $m^{-2}s^{-1}$. Net photosynthetic rate at light saturation($P_{max}$) of the upper four leaves in SNU-SG1 was much higher and sustained longer throughout grain-filling than HYVs and $F_1$ hybrids. The sustained high photosynthetic competence of SNU-SG1 during grain filling was ascribed to the longer maintenance of high mesophyll conductance that resulted from not only high chlorophyll content and its delayed degradation but also the slow degeneration of photosystem II(PS II) as judged by chlorophyll fluorescence($F_v/F_m$) of flag leaves. $F_1$ hybrids showed slow degeneration of photosystem II similar to the male parent SNU-SG1 while chlorophyll degradation pattern close to female parents, thus exhibiting a little higher $P_{max}$ than female parents. These results suggest that SNU-SG1 has a typical functional stay-green trait that can be utilized for increasing rice yield potential through the improved dry matter production during grain filling.

• 생명과학회지
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• 제32권10호
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• pp.743-748
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• 2022

부추는 아시아를 포함한 전세계적으로 분포하는 초본이다. 한국에서 부추는 양념용 채소와 국수용 고명에 사용된다. 질소비료, 인산비료, 칼리비료와 수분 스트레스가 부추(Allium tuberosum Rotter) 잎에 미치는 영향에 대해 조사하였다. 엽록소 a 함량은 10 mg/l 질소 비료에서 0.386였고, 50 mg/l에서는 0.584였다. 엽록소 a, b, 전체 엽록소량은 대조군에 비해 유의한 차이를 나타내었다(p<0.05). 엽록소 a, b, 전체 엽록소에 대한 피어슨 상관계수(Pearson's r)는 각각 0.940, 0.966, 0.971였다. 잎의 엽록소 a, b, 전체 엽록소는 인산비료인 경우 40 mg/l가 50 mg/l 시비보다 높았다. 인산 비료인 경우 10 mg/l에서 전체 엽록소량은 0.312였고 50 mg/l 일 때 0.589였다. 엽록소 효율과 습도와의 관계를 산출하였다. 광합성 효율의 척도로 기저 수준의 형광산율(Fo), 최대 형광산율(Fm), 전자소멸 상태(Fv), 최대 PSII 광계비율(Fv/Fm)의 기울기는 각각 -0.931, 0.972, 972, 0.950였다. 질소, 인산, 칼륨 비료와 가뭄스트레스는 부추의 엽록소함량과 효율성에 영향을 주었다.

• 한국약용작물학회지
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• 제28권1호
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• pp.1-8
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• 2020

Background: This study was conducted to investigate the effects of NaCl concentration on the photosynthetic parameters, chlorophyll fluorescence and growth characteristics of Crepidiastrum sonchifolium. Methods and Results: As treatments, we subjected C. sonchifolium plants to four different concentrations of NaCl (0, 50, 100 and 200 mM). We found that the photosynthetic parameters maximum photosynthesis rate (P_{N max}), net apparent quantum yield (Φ), maximum carboxylation rate (V_cmax), and maximum electron transport rate (J_max) were significantly reduced at an NaCl concentration greater than 100 mM. In contrast, there was an increase in water-use efficiency with increasing NaCl concentration, although in terms of growth performances, leaf dry weight, root dry weight, stem length, and total dry weight all decreased with increasing NaCl concentration. Furthermore, leakage of electrolytes, as a consequence of cell membrane damage, clearly increased in response to an increase in NaCl concentration. Analysis of the polyphasic elevation of chlorophyll a fluorescence transients (OKJIP) revealed marked decrease in flux ratios (Φ_PO, Ψ_O and Φ_EO) and the PI_abs, performance index in response to treatment with 200 mM NaCl, thereby reflectings the relatively reduced state of photosystem II. This increase in fluorescence could be due to a reduction in electron transport beyond Q^-_A. We thus found that the photosynthetic parameters, chlorophyll fluorescence and growth characteristics of C. sonchifolium significantly increased in response to treatment with 200 mM NaCl. Conclusions: Collectively, the findings of this study indicate that C. sonchifolium shows relatively low sensitivity to NaCl stress, although photosynthetic activity was markedly reduced in plants exposed to 200 mM NaCl.