• 환경생물
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• 제23권1호
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• pp.64-70
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• 2005

벼의 유묘 생육과 광합성 효율에 대한 저선량 방사선과 생장조절물질 간의 상승작용 효과를 확인하기 위해 4년 된 종자로 기내실험과 온실실험을 수행하였다. 기내실험에서 관찰한 종자 발아의 경우 방사선을 조사한 IBA 0.001 ppm 처리구에서 가장 높은 값을 보였다. 또한, 파종 6일 후 측정한 유묘 생육은 방사선 무 조사구보다 방사선을 조사한 GA₃와 IBA 처리구에서 대체로 높은 값을 보였으며, 그 중 IBA 0.001 ppm 처리에서 저선량 방사선과 생장조절물질간의 유의성 있는 상승작용 효과를 확인 할 수 있었다. 저선량 방사선을 조사 한 후 IBA 0.001 ppm을 처리하여 관찰한 온실 실험에서도 유묘 생육에서의 상승작용 효과를 확인할 수 있었다. 광합성 효율을 확인하기 위해 측정한 엽록소 형광은 생장조절물질에 의해서만 차이를 보여, IBA 처리에 의해 광계 2의 양자 수율을 나타내주는 Ф/sub PSⅡ/와 광화학적 소멸을 나타내는 qP는 증가하였고 비광화학적 소멸을 나타내는 형광지표인 qN은 감소하였다. 이러한 결과를 통해 저선량 방사선을 조사한 후 생장조절물질을 처리하였을 때 벼의 종자 발아와 더불어 생육이 두 요인간의 상승작용 효과로 촉진됨을 확인할 수 있었다.

• Journal of Photoscience
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• 제6권1호
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• pp.29-36
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• 1999

Chlorophasts are a central structural feature of stomatal guard cells. Guard cell chloroplasts have both photosystems I and II (PS I and II), carry out O2 evoluation , cyclic and noncyclic photophosporylation, and possess the Calvin-Benson cycle enzymes involved in CO2 fixation. These imply that guard cell chloroplasts have a normal photosynthetic carbon reduction pathway just like their mesophyll counterparts, indicating similar fuctional organization of thylakoid membranes in both types of mesophyll and guard cell chloroplasts. It has been, however, found that guard cell chloroplasts have distinctive and comparative properties in their photosynthetic performance. In this article, I review the intrinsic features on the light reaction of and carbon reduction by guard cell chloroplasts.

• Journal of Photoscience
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• 제5권4호
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• pp.169-174
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• 1998

Photosynthetic responses to dehydration were examined by the simulataneous measurement of O2 evolution and chlorophyll (Chl) fluorescence in green pepper leaves. Dehydration was induced by immersing the plant roots directly in the Hoagland solution containing varying concentration (2-30%) of polyethylene glycol(PEG-6000) . Water potential of the leaf was decreased time-and concentation -dependently by PEG-treatment. The decrease in water potential of leaf was correlated with the decrease in both the maximal photosynthesis (Pmax) and quantum yield of O2 evolution, but Pmax dropped more rapidly than quantum yield at all water deficit conditions tested. However, Chl fluorescence parameters were not affected much. Dehydration did not change the initial fluorescence (Fo) and maximum photochemical efficiency(Fv/Fm) of photosystem(PS) II. Both the photochemical quenching (qP) and non-photochemical quenching(NPQ) were not changed by dehydration under low PFR(50 $\mu$mols m-2s-1 ). In contrast, under high PFR(270$\mu$mols m-2s-1)qP was slightly decreased while NPQ was greatly increased. The fast induction kinetics of Chl fluroecence showed no change in Chl fluorescence pattern by dehydration at high PFR (640 $\mu$mols m-2s-1 ), but exhibited a significant drop in peak level(Fp)at low PRFR (70$\mu$mols m-2s-1 ). PS I oxidation and reduction kinetics revealed normal reduction but delayed oxidation to P-700+, suggesting no lesionin electron flow from PSII to PSI , but impaired electron transport to NADP+,These results suggest that water stress caused by PEG-treatment results in the reduction of photosynthesis, promarily due to the reducted electron trasport from PSI to NADP+ or hampered subsequent steps involving Calvin Cycle.

• 아시안잔디학회지
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• 제23권1호
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• pp.9-22
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• 2009

본 연구는 전 세계적으로 물 부족 현상으로 인한 물의 사용에 대한 관심이 증가함에 따라 네 종류의 난지형 잔디에 각기 다른 비율의 적자란수를 함으로써 식물의 생리학적인 반응, 즉 시각적 품질, 잎의 물 함량, 엽록소 함량, 광합성, 물 이용효율 등이 어떤 반응을 보이는지를 이해하고 그에 따른 상관관계를 분석 해보고자 했다. 결론적으로 20% 정도 적자 관수를 했을 때 식물은 약간의 스트레스를 받는 상태에서도 적자 관수를 하지 않은 식물과 비교했을 때 광합성량의 차이가 없었으며 가장 이상적인 생리학적인 반응을 보였다. 뿌리 발육 부분에 있어서도 적자관수를 통한 건조스트레스는 깊은 뿌리 생육을 촉진하는 관리방법으로 적용되었다. 다음 연구는 잔디가 각기 다른 토양 수분상태에서 일정하게 유지되었을때 지상부와 지하부의 생육에 따른 생리학적인 반응에 대한 연구로 확대되어야 할 것이다.

• 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.

• 환경생물
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• 제21권4호
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• pp.368-376
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• 2003

The UV-B sensitivity was tested for the intertidal species Chondrus ocellatus from Korea, by measuring photosynthesis estimated as effective quantum yield ($\Phi_{PSII}$) of photosystem II (PS II), growth and content and composition of photosynthetic pigments and UV-absorbing pigments (UVAPs). The $$\Phi_{PSII}$ of the alga decreased with increasing time of exposure to UV-B radiation, followed by fast and nearly full recovery indicating dynamic photoinhibiton. Fresh weight-based growth and pigment contents of C. ocellatus were not seriously affected by UV-B radiation. A single broad peak at 327 nm was obtained from methanol extracts of C. ocellatus, and the absorbance peak increased with increasing UV. The single peak was resolved into three peaks (311, 330 and 336 nm) by the fourth -derivative, and quantitative change in response to UV-B radiation occurred only at 330 nm. High performance liquid chromatography (HPLC) analysis of purified extracts indicated that three MAAs (mycosporine-like amino acids) are present, asterina 330, palythine and shinorine. Field observations during three growing months showed that C. ocellatus exhibit the highest amount of UVAPs in May followed by July and little trace in September, coinciding with the species' phenology. In an ecological context, dynamic photoinhibition as well as accumulation of UVAPs may enable the shallow water red alga C. ocellatus to be well adapted to high UV-B environments.

• Journal of Photoscience
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• 제8권1호
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• pp.1-7
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• 2001

The deteriorative effect of ultraviolet-B(UV-B) radiation on photosynthesis was assessed by the simultaneous measurement of O$_2$ evolution and chlorophyll(Chl) fluorescence in green pepper. UV-B was given at the intensity of 1 W$.$m$\^$-2/, a dosage often encountered in urban area of Seoul in Korea, to detached leaves. Both Pmax and quantum yield of O$_2$ evolution was rapidly decreased, in a parallel phase, with increasing time of UV-B treatment. Chl fluorescence parameters were also significantly affected. Fo was increased while both Fm and Fv were decreased. Photochemical efficiency of PSII(Fv/Fm) was also declined, although to a lesser extent than Pmax. Both qP and NPQ were decreased similarly with increasing time of UV-B treatment. However, PS I remained stable. The addition of lincomycin prior to UV-B treatment accelerated the decline in Fv/Fm to some extent, suggesting that D1 protein turnover may play a role in overcoming the harmful effect of UV-B. The amount of photosynthetic pigments was less affected than photosynthetic response in showing decline in Chl a and carotenoids after 24 h-treatment. Presumptive flavonoid contents, measured by changes in absorbance at 270 nm , 300 nm and 330nm, were all increased by roughly 50% after 8 h-treatment. Among antioxidant enzymes, activities of catalase and peroxidase were steadily increased until 12h of UV-B treatment whereas ascorbate perxidase, dehydroascorvate reductase and glutathione reductase did not show any significant change. The results indicate that deteriorative effect of UV-B on photosynthesis precedes the protection exerted by pigment synthesis and antioxidant enzymes.

• KSBB Journal
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• 제8권2호
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• pp.185-191
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• 1993

산소발생능에 있어 오랜 기간 안정성을 유지하는 세포와 분리 틸라코이드 막을 단세포성 남조류인 Synechococcus PCC7002로부터 PVA로 고정화하여 구할 수 있었다. 분리 틸라코이드 막 및 고정화한 세포나 틸라코이드 막의 흡수스펙트럼의 굽대가 청색쪽으로 3nm정도 전이하였다. PVA에 고정화한 세포나 틸라코이드 막은 $4^{\circ}C$에 보관할 경우 광합성에 의한 전자전달 활성, 특히 광계 2의 활성을 오랜기간 보존할 수 있었다. 세포를 고온에 처리하였을 때 Fo와 Fv가 증가하였으나 고정화한 후에는 Fo의 변화가 거의 없었다. 이 결과는 고정화가 열처리에 의한 광계 2 복합체의 손상 특히 물분해기구의 손상에 대해 보호작용을 할 수 있음을 시사한다.

• 한국작물학회지
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• 제48권6호
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• pp.506-515
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• 2003

이 논문은 한발저항성이 다른 6개 보리 품종의 한발에 따른 생장, 잎의 수분포텐셜(leaf water potential, LWP), 상대함수량(leaf relative water content, RWC), 삼투압(leaf osmotic potential, OP), 삼투조정(osmotic adjustment, OA), 팽압(leaf turgor pressure, LTP), 순광합섬, 기공전도도, 엽육전도도, 엽록소형광 등의 변화를 조사하여 비교한 결과를 요약하면 다음과 같다. 1 한발 처리시 토양수분포텐셜은 -0.05㎫이었고. 종료시에는 -0.29㎫로 저하하였다. Dicktoo-S 동보리 1호, Dicktoo-L, Dicktoo-T, 수원쌀보리 365호, 탑골보리 품종의 한발처리구 건물중은 각각 대조구(처리기간종 -0.05㎫ 유지)에 비하여 68%, 69%, 70%, 86%, 55%, 37%를 나타내어 Dicktoo 계통과 동보리1호의 한발저항성이 강하였고, 수원쌀보리 365호와 탑골보리는 한발저항성이 약하였다. 2. 한발저항성이 강한 품종은 삼투조정능력이 커서 한발처리에 따른 RWC와 LWP의 저하가 작았고 팽압유지능력이 컸다. 3. 한발처리에 따라 순광합성이 저하하였고 그 저하정도는 한발저항성이 큰 품종이 작았는데, 이는 한발저항성이 큰 품종이 기공전도도, 엽육전도도 및 PSII 최대양자수율(Fv/Fm)의 저하가 적었기 때문이었다. 4. 결론적으로 저항성이 큰 품종은 삼투조정에 의한 수분유지능력이 크고 이에 따라 광합성저하가 적어 상대적으로 생장의 감소가 적은 것으로 판단되었다.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1980년도 학술대회지
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• pp.151-170
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• 1980

Physiological response of Panax ginseng var. atropurpureacaulo (purple stem variety, Pg) to light was reviewed through old literatures and recent experiments. Canopy structure, growth, pigment, leaf anatomy, disease occurence, transpiration, photosynthesis (PS), leaf saponin, photoperiodism and nutrient uptake were concerned. P. ginseng var. xanthocarpus (yellow berry variety, Px) and Panax quinquefolius(Pq) were compared with Pg if possible. Compensation point(Cp) increased with increase of light and ranged from 110 to 150 at $20^{\circ}C$ but from 140 to 220 at $30^{\circ}C$ with 4 to 15 Klux indicating occurence of light and temperature-dependent high photorespiration. Characteristics of Korea ginseng to hate high temperature was well accordance with an observation 2000 years ago. Korea ginseng showed lower Cp and appeared to be more tolerant to high light intensity and temperature than American sheng although the latter showed greater PS, stomata frequency and conductance, chlorophyll and carotenoids. Px showed lower PS than Pg probably due to higher Cp. Total leaf saponin was higher in leaves grown under high light. Ratio or diol saponin and triol saponin(PT/PD) decreased with increase of light intensity during growing mainly due to decrease of ginsenoside $Rg_1$ but increase of ginsenoside Rd. Leaves of Pg and Px had $Rg_1$ but no $Rb_3$ which was only found as much as $20\%$ of total in Pq leaves, and decreased with increase of light intensity. Re increased in Pg and Px but decreased in Pq with increase of light. PT/PD in leaf ranged 1.0-1.5 in Pg and Px but around 0.5 in Pq. Korea ginseng has Yang characteristics(tolerant to high light and temperature), cultured under Eum(shade) condition and long been used for Yang efficacy (to build up energy) while Pq was quite contrary. Traditional low light $intensity(3-8\%)$ for Korea ginseng culture appeared to be strongly related to historical unique quality. Effect of light quality and photoperiodism was not well known. Experiences are long but scientific knowledge is short for production and quality assessment of ginseng. Recent scientific knowledge of ginseng should learn wisdom from old experiences.