• 환경생물
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• 제23권1호
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• pp.47-51
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• 2005

3주간 정상적으로 생장한 닭의장풀을 Hoagland 용액 (대조구, 100 μM Cd/sup 2+/, 100 μM Cd/sup 2+/ + 100 μM ABA, 100 μM Cd/sup 2+/+50 mM KCl)에서 1주간 수경재배 한 후 생장, 엽록소 함량, 엽록소 형광, 수분 스트레스와 Cd/sup 2+/의 축적을 조사하여 Cd/sup 2+/ 축적과 식물의 생리적 반응과의 연관성을 찾고자 하였다. 식물의 생장에서 Cd/sup 2+/과 Cd/sup 2+/+ABA 처리구는 대조구에 비해 각각 71%와 81%생장이 감소하였고, Cd/sup 2+/+KCl 처리구는 Cd/sup 2+/ 처리구와 생장에 큰 차이가 없었다. 엽록소 함량은 Cd/sup 2+/, Cd/sup 2+/+ABA, Cd/sup 2+/+KCl 처리구에서 대조구에 비해 각각 32%, 41%, 29% 억제되었다. 엽록소 형광 측정의 경우 Cd/sup 2+/ 처리구는 대조구에 비해 모든 광도에서 Fv/Fm 비율이 14∼20% 감소하였다. Cd/sup 2+/+ABA 처리구는 Fv/Fm 비율이 23% 내외에서 감소하였으며, Cd/sup 2+/+KCl 처리구는 Cd/sup 2+/ 처리구와 Fv/Fm 비율에 큰 차이가 없었다. 수분 스트레스에 대한 Cd/sup 2+/과 ABA 처리 효과는 Cd/sup 2+/ 처리구에서 대조구에 비해 2.5배, Cd/sup 2+/+ABA 처리구에서 3배, Cd/sup 2+/+KCl 처리구에서 2.25배 각각 수분 스트레스가 증가하였다. Cd/sup 2+/ 수송에 대한 ABA의 효과를 살펴보면, Cd/sup 2+/+ABA 처리구에서 ABA는 Cd/sup 2+/ 수송을 억제하거나 촉진시키지는 않았지만 Cd/sup 2+/의 뿌리 축적을 약 13% 심화시켰다. 반면에 KCl은 뿌리 내 Cd/sup 2+/ 축적을 약 60% 억제시켰다. 따라서 대표적인 스트레스 내성 호르몬 ABA는 Cd/sup 2+/축적으로 인해 발생된 식물의 생리적 독성을 완화시켜 주지 못했으며. 오히려 독성을 증가시켰다.

• 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.

• 한국환경과학회지
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• 제11권10호
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• pp.1023-1030
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• 2002

The effects on photosynthesis of NaCl(0, 0.2, 0.4, 0.6, 0.8 or 1.0 M) were examined in etiolated barley seedlings. Chlorophyll(Chl) a, Chl b and carotenoid contents, Chl a fluorescence and quenching coefficients of Chl fluorescence have been determined in the primary leaves of etiolated barley seedlings cultivated under low light(60 $\mu$㏖ $m^{-2}\;s^{-1}$). Chl a, b, and carotenoid contents were decreased remarkably in comparison with the control at 0.4 M NaCl. However, the value of Fo and Fv were decreased at 0.6 M NaCl and the ratio of Fv/Fm were deceased at 1.0 M NaCl. Chlorophyll synthesis was seriously inhibited from 0.4 M NaCl, and the photosynthetic electron transport system was inhibited from 0.6 M NaCl. Quantum of photosystem II reaction center was inhibited at 1.0 M NaCl. The effects of NaCl on the Chl content were raised in a 6 hrs, but the effects of NaCl on the value of Fo, Fv and Fv/Fm were raised in 30 hrs. The value of qP was decreased in comparison with the control at all concentrations, but there was a small change in the value qE. These results provide evidence that NaCl inhibited effects of various concentration of NaCl were inhibited quinone redox, however, proton gradient between thylakoid membranes was little damaged.

• 한국환경농학회지
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• 제26권3호
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• pp.239-245
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• 2007

The effect of ultraviolet-B (UV-B) radiation on photosynthesis was studied by the simultaneous measurements of $O_2$ evolution and chlorophyll (Chl) fluorescence in tobacco leaves. When the tobacco leaves were teated with UV-B (1 $W{\cdot}m^{-2}$), the maximal photosynthetic $O_2$, evolution (Pmax; 4.60 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) at 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) was decreased with increasing time of UV-B treatment showing 80% decline after 4 h treatment. Chl fluorescence parameters were also affected by ultraviolet-B. Fo was increased while both Fm and Fv were decreased, resulted in the decreased of photochemical efficiency of PSII (Fv/Fm). Non-radiative dissipation of absorbed light as heat as estimated as NPQ (Fm/Fm' - 1) was also decreased with increasing time of UV-B treatment while the extent of photochemical quenching (qP) was not changed. Thus, the ratio of (1-qP)/NPQ parameter was also increased with increasing time of UV-B treatment indicating PSII is under the threat of photoinhibition. The result indicate that UV-B primarily decreases the capacity to dissipate excitation energy by trans-thylakoid pH, which in turn inhibits PSII activity.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.60-60
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• 2019

개비자나무[Cephalotaxus harringtonia (Knight ex Forbes) K. Koch]와 비자나무[Torreya nucifera (L.) Siebold & Zucc.]의 3년생 실생묘를 유리온실에 재배하면서 실험재료로 사용하였다. 실내의 광량을 측정하여 10, 50, 100 및 200 PPFD (${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$)로 설정하였다. 광량을 제외한 광주기(12/12 h), 온도($25{\pm}1^{\circ}C$), 습도($55{\pm}3%$) 및 관수(1회/3일)주기를 일정하게 유지시킨 밀실에서 8주간 재배하였다. 유리온실에서 재배중인 식물과 광량별 처리구의 초장, 줄기직경, 엽수, 엽장, 엽폭, 엽록소함량(SPAD) 및 광화학반응을 평가하였다. 개비자나무의 생육결과, 모든 광량조건에서 줄기직경과 엽록소함량이 증가하는 경향을 보였으며, 초장, 엽폭의 경우 대조구와 유의한 차이가 없었다. 스트레스지수(Fm/Fo), 최대양자수율(Fv/Fm) 및 광계II 성능지수(Pi_Abs)는 대조구에 비해 모든 광량에서 증가하는 경향을 나타냈다. 10 PPFD의 광량을 제외한 처리구에서 재배된 비자나무의 초장, 줄기직경, 엽장, 엽폭은 대조구와 유사한 경향을 나타냈다. 한편, 엽수와 엽록소함량은 대조구에 비해 우수하였다. Fm/Fo, Fv/Fm, Pi_Abs 및 비광학적 에너지의 손실(DIo/RC)은 모든 광량처리구에서 대조구에 비해 유의적으로 높은 측정값을 나타냈다.

• 한국초지조사료학회지
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• 제38권3호
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• pp.170-174
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• 2018

Environmental stresses caused by climate change, such as high temperature, drought and salinity severely impact plant growth and productivity. Among these factors, high temperature stress will become more severe during summer. In this study, we examined physiological and molecular responses of maize plants to high temperature stress during summer. Highest level of $H_2O_2$ was observed in maize leaves collected July 26 compared with June 25 and July 12. Results indicated that high temperature stress triggers production of reactive oxygen species (ROS) in maize leaves. In addition, photosynthetic efficiency (Fv/Fm) sharply decreased in leaves with increasing air temperatures during the day in the field. RT-PCR analysis of maize plants exposed to high temperatures of during the day in field revealed increased accumulation of mitochondrial and chloroplastic small heat shock protein (HSP) transcripts. Results demonstrate that Fv/Fm values and organelle-localized small HSP gene could be used as physiological and molecular indicators of plants impacted by environmental stresses.

• Journal of Photoscience
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• 제5권2호
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• pp.53-61
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• 1998

Using a squash plant, a chilling-sensitive species, and a spinach plant, a chilling-resistant one, effects of chilling temperature on the photosynthetic machinery were studied in terms of chlorophyll fluorescence. When thylakoid membranes were isolated and subjected to incubation at different temperatures, spinach showed stable photosystem II activity at the low temperature side, in contrast to squash which showed quite severe inactivation at low temperature. When parameters of chlorophyll fluorescence were examined, chilling in darkness did not affect either Fv/Fm or photochemical and non-photochemical quenching, in both types of plants. However, chilling of squash plants under irradiance of medium intensity caused a specific decrease in Fv/Fm accompanied by a decline in energy-dependent quenching. Contrastingly, photosystem li of spinach plants were not much affected by light-chilling. When the pool size of zeaxanthin was examined after exposure to high light at different temperatures, squash plants was shown to have a much lower content of antheraxanthin + zeaxanthin, as compared to spinach plants, during low-temperature photoinhibition. These results suggest that chilling-sensitive plants have low capacity to dissipate excitation energy nonradiatively, when they are exposed to low-temperature photoinhibition, and, as a consequence, more vulnerable to photoinhibitory, damage to the photosynthetic apparatus.

• Journal of Plant Biology
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• 제39권4호
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• pp.309-314
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• 1996

Developmental of photosynthetic pigments and changes in chlorophyll fluorescence of dark-grown rice seedlings were studied during greening. Light-illumination stimulated accumulations of total chlorophylls and carotenoids in leaves of etiolated seedlings, accompanied by a decrease in the ratio of chlorophyll a to chlorophyll b. When the composition of carotenoids was analyzed, violaxanthin level was shown to increase up to 24 h after the beginning of light illumination, followed by a subsequent decline. In contrast to this, zeaxanthin level increased consistently with progress of deetiolatin. The role of zeaxanthin is discussed in relation to chlorophyll fluorescence quenching. A study on chlorophyll fluorescence kinetics of the rice seedlings being deetiolated showed a time-dependent increase in Fv/Fm (yield of variable fluorescence/maximum yield of fluoresecnece) ratios, indicating that greening is responsible for the activation of photochemical reaction centers of the photosystem. When chlorophyll fluorescence quenching was examined, qNP (nonphotochemical quenching) and qE (energy-dependent quenching) exhibited a time-dependent decline with progress of greening. The presented results indicate that greening-induced development of the photosynthetic machinery is associated the conversion of the carotenoid violaxanthin to zeaxanthin, suggesting that zeaxanthin synthesized in the illuminated leaves may provide the protection from the damage when etiolated plants are exposed to light.

• 한국연초학회지
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• 제23권2호
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• pp.109-114
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• 2001

A CAB cDNA vector(pKGCAB), encoding the light harvesting chlorophyll a/b binding protein in Korean ginseng (Panax ginseng C. A. Meyer), was constructed with the CaMV35S promoter of plant expression vector. The chimeric vector was transformed into tobacco(Nicotiana tabacum cv. NC 82) using Agrobacterium tumefaciens LBA 4404 strain, and the transgenic tobacco plant CAB-TP2 was selected. Photosynthetic rates of the CAB-TP2 plant at before-flowering stage were increased about 20% under low irradiance conditions of quantum 100 and 500 $\mu$mol.m$^{-2}$ s$^{-1}$ , however, the rates were similar to those of NC 82 under quantum 1000 and 2000 $\mu$mol.m$^{-2}$ s$^{-1}$ conditions. The plants were germinating under low- or normal irradiance condition and the quantum yield of photosystem III were measured. The differences of the Fv/Em values between conditions were 0.07 and 0.01 in NC 82 and CAB-TP2, respectively. The mature leaves in the position 8-10 of the CAB-TP2 at before-flowering stage revealed l0% higher Fv/Fm values in range of 0.759 to 0.781 and 40% more chlorophyll contents of 70-93mg/$m\ell$ than those of normal NC 82. These data suggest the possibility that the increase in photosynthetic activity of leaves under low light intensity in the canopy of CAB-TP2 transgenic tobacco might lead to increase the quality of lower tobacco leaves.

• 환경생물
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• 제21권3호
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• pp.234-239
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• 2003

3주간 정상적으로 생장한 닭의장풀을 Hoagland용액 ($\pm 100 \mu M \;Cd^{2+}, 100 \mu M \;Cd^{2+}+10 \mu M\;IAA,100 \mu M\; Cd^{2+}+100 \mu M \; IAA,100 \mu M \; Cd^{2+} +1 \mu M \; IAA)$에서 3주간 수경재배 한 후 생장, 기공개폐, 엽록소 함유량, 엽록소 형광 및 수분퍼텐셜을 조사하였다. Hoagland용액에 $Cd^{2+}$ 처리시 3주 동안 2.0 cm 생장했으나, 대조구는 7.0 cm생장했다. 반면에 카드뮴에 10$\mu$M IAA를 같이 처리한 경우는 3주 동안 3.7 cm자랐으며, 100 $\mu$M IAA를 같이 처리하면 3주 동안 5 cm그리고 1mM IAA의 경우는 3.3 cm 생장하였다. $Cd^{2+}$은 기공열림을 촉진하였으며, 아울러 IAA첨가는 $Cd^{2+}$을 단독처리 한 경우보다 기공열림을 더 촉진하였다. 엽록소 함량의 변화는 $Cd^{2+}$ 처리구에서 뚜렷하게 관찰되었다. Cd$^{2＋}$ 처리구는 대조구에 비해 3주 때 엽록소 함량이 13%억제되었다. $Cd^{2+}$과 IAA를 함께 처리한 경우는 10 $\mu$M과 100 $\mu$M에서는 뚜렷한 엽록소 함량의 변화가 관찰되지 않았다. 1 mM IAA 처리구에서는 약 9% 엽록소 함량이 감소하였다. 모든 처리구에서 정상적인 엽록소 a/b비율을 보여주었으나, $Cd^{2+}$처리구에서 3주 배양한 경우 2.38을 보여주었다. Fv/Fm 측정 결과 $Cd^{2+}$ 처리는 Fv/Fm값에 영향을 주었다. 카드뮴 처리 1주에는 큰 변화가 없었으나,2주와 3주 처리시에는 대조구에 비해 각각 9%와 11% 억제되었다. $Cd^{2+}$처리시 약 3주 후에 약 67%가 수분퍼텐셜이 감소하였다. 반면에 $Cd^{2+}$에 IAA를 다양한 농도에서 첨가하면 수분퍼텐셜의 변화는 미미하였다. 위의 결과들로부터 IAA는 식물의 생장, 엽록소 함량,Fm/Fv그리고 수분퍼텐셜에서 $Cd^{2+}$에 의한 심각한 독성을 뚜렷하게 완화시키는 것으로 사료된다.