• 한국환경농학회지
• /
• 제13권2호
• /
• pp.183-190
• /
• 1994

작물의 광합성 상태를 신속, 정확하게 알아내는 것은 농업생산력 향상은 물론 각종 환경요인에 의해서 작물이 받게 되는 stress 평가를 하기 위해 중요한 일이므로, 형광분석법을 시설재배작물의 광합성 상태 측정에 이용하고자 배추와 딸기를 식물 재료로 하여 비닐하우스의 재배 환경 요인으로 작용하는 인자(광도, 온도, NaCl 농도, 토양수분)들이 엽록소형광에 미치는 영향을 조사하였다. 광도가 낮아짐에 따라 배추와 딸기의 Fv/Fm 비가 증가되었는데, 이는 광도가 낮아짐에 따라 PS II 반응센터의 광에너지 전환효율이 낮았기 때문이라고 생각된다. 특히, Fv/Fm 비가 $CO_2$ analyzer에서 측정된 광합성능과 역비례 관계를 보인 것은 Fv/Fm 비가 식물의 광합성상태와 매우 밀접한 관계가 있음을 나타낸 것이다. 온도처리의 경우 처리온도가 높아짐에 따라 Fv/Fm 값이 높아졌다. NaCl 처리에 의해서 Fv/Fm 비와 광합성능이 낮아졌으며 딸기보다 배추에서 더 컸다. 또한 토양수분함량이 적어짐에 따라 Fv/Fm 비가 감소하였는데 이는 Fv/Fm 비가 광합성과 수분 stress 생리 관계를 연구하는데 좋은 자료로 활용될 수 있음을 보인 결과로써, 감귤의 경우도 토양 수분 함량이 낮을 때 Fv/Fm 비가 낮은 값을 보여 감귤나무의 수분 stress 정도를 In vivo 상태에서 경시적으로 관찰할 수 있는 예민한 방법으로 형광 분석법이 활용될 수 있으리라 기대된다.

• Journal of Forest and Environmental Science
• /
• 제37권4호
• /
• pp.315-322
• /
• 2021

The aim of this study was to investigate the sensitivity to environmental stress, and changes in the photosynthesis capacity in Abies koreana seedlings by age and to suggest the most effective age for restoration. To identify these physiological characteristics of A. koreana, the chlorophyll fluorescence and photosynthetic capacity of 1-, 2-, 3-, 5- and 6-year-old A. koreana seedlings were observed from June 2020 to June 2021. The maximum quantum efficiency of Photosystem II (Fv/Fm), a chlorophyll fluorescence measurement parameter, was strongly positively correlated with the monthly average temperature (1-year-old seedling: r=0.8779, 2-year-old seedling: r=0.8605, 3-year-old seedling: r=0.8697, 5-year-old seedlings: r=0.8085, and 6-year-old seedlings: r=0.8316). The Fv/Fm values were the lowest in winter (November 2020-March 2021). In addition, the Fv/Fm values of 1-, 2-, and 3-year-old seedlings in winter were lower than that of 5- and 6-year-old seedlings, while the Fv/Fm values in summer were relatively higher than those in winter. Further, the Fv/Fm values of seedlings of all ages decreased in August 2020, when the monthly average temperature was the highest. In particular, 1-year-old to 3-year-old seedlings showed Fv/Fm values less than 0.8. Further, the photosynthetic capacity measured in August 2020 increased with increasing seedling age. The analysis of variance results for summer Fv/Fm values showed significant differences in age-specific averages (p<0.05), and Duncan's multiple range test showed significant differences between 5- and 6-year-old seedlings and 1-, 2-, and 3-year-old seedlings (p<0.05). These results suggested that the 5- and 6-year-old seedlings were less sensitive to environmental stress and showed better photosynthetic capacity than the 1-, 2-, and 3-year-old seedlings. Therefore, 5-year-old or older A. koreana seedlings can be used as restoration materials because they can show increased adaptability and stable growth during transplantation due to their relatively high environmental resistance and photosynthetic capacity.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2002년도 제9차 국제심포지움 및 추계정기학술발표회
• /
• pp.12-12
• /
• 2002

The chlorophyll fluorescence combined with the O-J-I-P transients were examined in the leaves of the crinum plants (Crinum asiaticum var. japonicum BAK.), in order to satisfy the demand for rapid in vivo measurement of vitality, and to apply easily to approach questions of economical interest concerning the plant vitality. The photosynthetic efficiency, Fv/Fm, of crinum plants dramatically decreased depending on temperature drop in winter. In summer, the Fv/Fm values was lower in day time than at dawn and night, suggesting that photosynthetic efficiency is chronically photoinhibited in day time. In winter, there was no prominent diurnal fluctuations of Fv/Fm values. However, based on the O-J-I-P transient, PI$\_$NO/ and SFI$\_$NO/ dramatically increased at noon in summer, and $\psi$o/(1-$\psi$o) diurnally fluctuated in winter. These results indicated that vitality indexes such as PI$\_$NO/, SFI$\_$NO/ and $\psi$o/(1-$\psi$o) can be used as the indicators for in vivo measurement of environmental stresses.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2002년도 심포지엄
• /
• pp.88-95
• /
• 2002

The chlorophyll fluorescence combined with the O-J-I-P transients were examined in the leaves of the crinum plants (Crinum asiaticum var.japonicum BAK.), in order to satisfy the demand for rapid in vivo measurement of vitality, and to apply easily to approach questions of economical interest concerning the plant vitality. The photosynthetic efficiency, Fv/Fm, of crinum plants dramatically decreased depending on temperature drop in winter. In summer, the Fv/Fm values was lower in day time than at dawn and night, suggesting that photosynthetic efficiency is chronically photoinhibited in day time. In winter, there was no prominent diurnal fluctuations of Fv/Fm values. However, based on the O-J-I-P transient, PI$\_$NO/ and SFI$\_$NO/ dramatically increased at noon in summer, and $\psi$ο/(1-$\psi$ο) diurnally fluctuated in winter. These results indicated that vitality indexes such as PI$\_$NO/, SFI$\_$NO/ and $\psi$ο/(1-$\psi$ο) can be used as the indicators for in vivo measurement of environmental stresses.

• Journal of Photoscience
• /
• 제5권1호
• /
• pp.17-22
• /
• 1998

Changes of chlorophyll fluorescence and xanthophyll cycle pigment contents in maize leaves were investigated dunng desiccation in darkness or in the light. In darkness, a drastic dehydration of detached maize leaves down to 50% relative water content (RWC) affected photochemical efficiency of photosystem II (Fv/Fm) and pht)tochemical quenching (qP) only slightly. In contrast, desiccation in the light with a moderate intensity led to a pronounced reduction in Fv/Fm with a Fo quenching when RWC was greater than 70%. This reduction in Fv/Fm could be recovered in darkness under hutrod condition. In leaves with RWC below 70%, significant reduction in Fv/Fm was accompanied by an increase of Fo, which could not be reversed within 5 h in darkness under humid condition. The nonphotochemical quenching increased during desiccation in the light with a concomitant rise in zeaxanthin at the expense of violaxanthin. Pretreatment with dithiothreitol (DTT), an inhibitor of zeaxanthin synthesis, inhibited the development of nonphotochemical quenching and prevented the xanthophyll interconversion during desiccation in the light. These results suggest that even light with a moderate intensity becomes excessive under dehydration and zeaxanthin-associated photoprotection of photosynthetic apparatus against photodamage is involved, but the protection is not complete against severe desiccation.

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

• 생명과학회지
• /
• 제20권8호
• /
• pp.1173-1180
• /
• 2010

Salt stress가 벼 잎 내 광합성 효율과 ascorbate peroxidase (APX) 활성에 미치는 영향을 조사하였다. 염 농도가 증가(NaCl, 100-300 mM) 할수록 Fv/Fm 값이 감소한 반면, $H_2O_2$ 양과 APX 활성은 증가하였다. APX isoforms 중 APX 1 (stromal)은 300 mM NaCl 처리 시 활성이 거의 나타나지 않는 반면, chilling이나 drought 처리 시에는 변화가 없었다. 또한 gel 상에서의 서로 다른 APX isoforms의 활성이 유전자 발현에서도 확인이 되는지를 알아보기 위해 RT-PCR을 수행하였다. 구획별 APX isoforms의 RT-PCR 수행 결과, cytosolic/thylakoid bound APX 발현양은 증가한 반면, stromal APX 발현은 매우 감소하였다. 이러한 실험 결과는 salt에 의해 구획별로 APX 활성이 영향을 받음을 나타낸다.

• 환경생물
• /
• 제26권1호
• /
• pp.15-21
• /
• 2008

Ionizing radiation causes many alterations in photosynthetic machineries. However, there is no information about effects of ionizing radiation on the development of photosynthetic machineries in plants. We investigated the greening of etiolated mung bean seedlings after gamma-irradiation of 50 to 300 Gy. The irradiation inhibited seedling growth with great dependence on the radiation dose. In particular, growth of stems was more affected than that of hypocotyls. Irradiated leaves showed inhibition in growth, aberration in morphology, and yellowing in color depending on the radiation dose. Contents of photosynthetic pigments such as chlorophylls and carotenoids were significantly decreased in the irradiated leaves. The apparent electron transport rate for photosynthesis, ETR, was similarly changed depending on the radiation dose. However, the maximal photochemical efficiency of Photosystem II (PSII), Fv/Fm, was little affected by the irradiation. Moreover, the 50-Gy seedlings maintained the control level of light saturating for photosynthesis and showed slightly higher Fv/Fm values in spite of significant decreases in the photosynthetic pigment content and ETR. These results suggest that the inhibition of the overall photosynthetic capacity couldn’t be causally relatqaed with the repression in the initial development of irradiated seedlings and that the overall photosynthetic machineries can develop and work to some extent as a concerted system for photosynthesis even after exposure to acute doses of ionizing radiation.

• Journal of Ginseng Research
• /
• 제22권2호
• /
• pp.102-113
• /
• 1998

This experiment used chlorophyll fluorescence techniques to assess the effect of irradiant during leaf development on photoinhibition of photosynthesis in Panax ginseng. Seedlings of p. ginseng were grown in the 91asshouse at four shade levels. The maximum mid-day irradiant in each treatment between emergence (January 4) and completion of the experiment (February 25) was 1220, 485, 235, 125 $\mu$mol/$\textrm{m}^2$/s. To assess the rapidity of photosynthetic readaptation to changes in light levels, fluorescence parameters (Fo, F, Fm, Fm', AF/Fm;, Fv/Fm) were measured for three days before and after transfer of plants (on February 21) from each light treatment into each of the other light treatments. Before transfer, dark adapted values of Fv/Fm in the 1220 (0.699) and 485 (0.739) treatments were different from each other and lower than values in the 235 (0.764) and 125 (0.768) treatments, indicating mild photoinhibition. Patterns of change in F during the day also differed between treatments, with low light treatments tracking irradiant levels, but F in the high light treatment (1220) declined in the morning, presumably due to fluorescence quenching. Although plants grown at high irradiant had relatively low photosynthetic efficiency, relative electron transport rate was greater than in lower irradiant treatments. After transfer, plants adopted the daily pattern of change in F of the treatment to which they were moved with little change in absolute levels of F, except in plants transferred from the highest (1220) to the lowest light level (125), where F increased over the course of the three days following transfer. After plants were transferred, Fm' converged on values similar to those in plants raised in the treatments to which they were moved. Values of Fv/Fm in plants moved from low to high light declined dramatically, but there was no decline in plants from 485 moved to 1220. Values of Pv/Fm in plants that were moved from high light to lower light increased to values above those recorded in plants raised in the lower light treatments. Reductions in quantum efficiency caused by photoinhibition at high irradiant may be more than compensated for by higher electron transport rates, although evidence suggests that under high irradiant this tends to be balanced by reduced leaf area and earlier senescence. Chlorophyll fluorescence techniques appear capable of indicating effects of irradiant induced stress in ginseng, yielding results comparable to those obtained with gas exchange techniques but in less time and with greater replication.

• Journal of Plant Biotechnology
• /
• 제30권4호
• /
• pp.399-403
• /
• 2003

환경스트레스에 대한 항산화효소의 보호효과를 이해하고 효과적인 스트레스내성 식물을 개발하기 위하여 CuZnSOD와 APX를 엽록체에 발현시킨 형질전환식물체 (CA식물체)에 강한 빛 (highlight, 1,100$\mu$mol m$^{-2}$ sec$^{-1}$)과 4$^{\circ}C$ chilling을 처리하였다. CA식물체 잎절편에서의 보호효과를 CuZnSOD을 도입한 SOD식물체, APX을 도입된 APX식물체 및 비형질전환식물체 (NT식물체)의 것과 비교하였다. CA식물체의 광계2에서의 광합성 효율 (Fv/Fm)은 highlight와 4$^{\circ}C$ chilling복합처리 1시간째에서 NT식물체에 비해 약 15%의 보호효과를 나타내었고, 광계1에서의 P700 redox state는 처리 후 3시간째에 약 23%의 보호효과를 나타내었다. SOD식물체와 APX식물체의 복합처리에 대한 보호효과는 CA식물체와 NT식물체의 중간 효과를 나타내었다. 이러한 결과는 엽록체에서 CuZnSOD와 APX의 동시발현이 highlight와 chilling에 의한 산화스트레스를 극복하는 데 매우 중요하게 관여함을 직접적으로 제시하는 것이다.