• 한국환경농학회지
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• 제6권2호
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• pp.73-76
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• 1987

들깨 수원(水原) 8호(號)(Perilla frutescens Suwon No. 8)에 $SO_2$를 접촉(接觸)시켰을 때 일어나는 광합성색소(光合成色素)의 변화(變化)에 대(對)한 $SO_2$농도(濃度), 접촉시간(接觸時間), 광,(光) 활성산소(活性酸素)와 무기(無機) $SO_3\;^{-2}$의 영향(影響)을 관찰분석(觀察分析)한 결과(結果)는 다음과 같다. 1. $SO_2$농도(濃度)가 높아지고 접촉시간(接觸時間)이 길어질수록 피해(被害)가 심해저 엽록소(葉綠素)의 파괴(破壞)도 많았다. 2. $SO_2$ gas접촉에 의하여 엽록소(葉綠素)a가 엽록소(葉綠素)b 보다 쉽게 분해(分解)되었으며 또한 carotinoid도 엽록소(葉綠素)b보다 쉽게 분해(分解)되는 것으로 추정된다. 3. 들깨의 $SO_2$에 의한 엽록소파괴(葉綠素破壞)는 $SO_2$에 의한 직접적(直接的)인 영향(影響)으로 파악되었고, 이 때에 광(光)이 필수적(必須的)으로 필요하며, 물이 광분해(光分解)로 생성(生成)되는 $O_2^-$가 $SO_2$와 함께 엽록소분해(葉綠素分解)에 중심적(中心的)인 역할을 하는 물질이었다.

• Molecules and Cells
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• 제38권5호
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• pp.390-395
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• 2015

Degradation of chlorophyll (Chl) by Chl catabolic enzymes (CCEs) causes the loss of green color that typically occurs during senescence of leaves. In addition to CCEs, STAYGREEN1 (SGR1) functions as a key regulator of Chl degradation. Although sgr1 mutants in many plant species exhibit a staygreen phenotype, the biochemical function of the SGR1 protein remains elusive. Many recent studies have examined the physiological and molecular roles of SGR1 and its homologs (SGR2 and SGR-LIKE) in Chl metabolism, finding that these proteins have different roles in different species. In this review, we summarize the recent studies on SGR and discuss the most likely functions of SGR homologs.

• 환경생물
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• 제21권4호
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• pp.415-421
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• 2003

Chlorophyll-a and its degradation products (pheopigment) contained in the sediment were determined to evaluate the eutrophication status in the downstream of Nakdong River. The chlorophyll-a and pheopigment concentrations of sediment ranged 11-646 mg $\mu \textrm m^{-2}$ (mean 172 mg $\mu \textrm m^{-2}$) and 48-1,564 mg $\mu \textrm m^{-2}$ (mean 454 mg $\mu \textrm m^{-2}$) over 11 sampling stations of the Nakdong River. The chloropigment concentrations in this local area were higher than other values reported previously and this river waters showed hypertrophic status in view of sedimentary chloropigment. Total chloropigment standing crops of sediment, which are the residuals after the longterm degradation, were 2.2-3.6 fold higher than chlorophyll-$\alpha$ contents of overlying water. The amounts of chloropigments of sediment suggest a large contribution of phytoplankton to the sediment. While chloropigment standing crops are evaluated with organic-C and nitrogen contents, the algal contribution to the carbon and nitrogen pool of the sediment were estimated to be approximately 30% and 40%, respectively.

• 한국식품영양과학회지
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• 제30권3호
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• pp.377-381
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• 2001

Chlorophyll a and b, pheophytin a and b and $\beta$-carotene, crude chlorophylls and carotenoids (CCC) extracts of mustard leaf kimchi were isolated by DEAE-sepharose CL-6B and Sepharose CL-6B colume and TLC. The effects of chlorophyll a and b, pheophytin a and b and $\beta$-carotene on linoleic acid autoxidation were examined by the determination of peroxide value and conjugated dienoic acid content. Among them, chlorophyll a showed greater antioxidative activity than others, followed by chlorophyll b, pheophytin a, pheophytin b and $\beta$-carotene. Degradation of pheophytin b was observed to be slower than others and $\beta$-carotene showed highest degradation level during the autoxidation reaction of linoleic acid.

• 한국수산과학회지
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• 제6권1_2호
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• pp.27-36
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• 1973

The effect of water activity on degradation of pigments in dried lavers, Porphyra tenera Kjellm. was examined when stored at room temperature for fifty days. Chlorophyll pigment was extracted with methanol-petroleum ether mixture solvent(2:1 v/v), partitioned in ether, and analysed spectrophotometrically at 662 nm as chlorophyll a. The degradation products of chlorophyll were isolated on sugar-starch column(85:15 w/w) with n-propanol-petroleum ether solution(1:200 v/v) as a developing solvent. The isolated green colored zones were analysed individually at the wavelengths of 650, 662, and 667 nm as allomerized product, chlorophyll a retained, and pheophytin formed respectively. Carotenoida were also extracted with the methanol mixture solvent, partitioned in ether, and finally redissolved in acetone after the evaporation of ether in a rotary vacuum evaporator. The total carotenoid content was measured as lutein at 450 nm. From the results, it is noted that the rate of chlorophyll degradation reached a minimum at 0.11 to 0.33 water activity while progressively increased at higher moisture levels resulting in rapid conversion of chlorophyll to pheophytin. At lower activity, autocatalysed oxidizing reaction like allomerization seemed prevailing the acid catalysed conversion reaction. The loss of carotenoid pigment was also greatly reduced at the range of 0.22 to 0.34 water activity with much faster oxidative degradation at both higher and extremely lower moisture levels. These two moisture levels indicated above at which the both pigments exhibited maximum stability are considerably higher than the BET monolayer moisture which appeared 7.91 percent on dry basis at Aw=0.10 calculated from the adsorption isothermal data of the sample at $20^{\circ}C$. The rate of pigment loss in heat treated samples at 60 and $100^{\circ}C$ for 2 hours prior to storage somewhat decreased, particularly at higher moisture levels although the final pigment retention was not much stabilized.

• 생명과학회지
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• 제6권4호
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• pp.299-303
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• 1996

미국사시나무(Populus tremuloides)의 삽목개체에 오존이 엽록소함량의 변화에 미치는 영향을 조사하였다. 오존은 일일 6시간씩, 주 3일간 연속적으로 open-top chamber에서 fumigation 하였다. 오존처리는 괴사반점과 광범위한 chlorosis 등 잎 조직에 심각한 상해를 발생시켰다. 오존처리에 의한 엽록소의 분해는 완전히 성숙한 잎에서 현저하게 관찰되었으나 어린 잎에서는 분해가 거의 보이지 않았다. 오존처리에 대한 엽록소의 반응은 실험 전 기간에 걸쳐 모든 실험대상식물에 있어 일정한 양상을 보였다. 또한 clone 별로 오존 민감성에 따라 엽록소함량의 변화에 상당한 유전적 변이를 보였다.

• 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.

• Molecules and Cells
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• 제40권10호
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• pp.773-786
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• 2017

The loss of green coloration via chlorophyll (Chl) degradation typically occurs during leaf senescence. To date, many Chl catabolic enzymes have been identified and shown to interact with light harvesting complex II to form a Chl degradation complex in senescing chloroplasts; this complex might metabolically channel phototoxic Chl catabolic intermediates to prevent oxidative damage to cells. The Chl catabolic enzyme 7-hydroxymethyl Chl a reductase (HCAR) converts 7-hydroxymethyl Chl a (7-HMC a) to Chl a. The rice (Oryza sativa) genome contains a single HCAR homolog (OsHCAR), but its exact role remains unknown. Here, we show that an oshcar knockout mutant exhibits persistent green leaves during both dark-induced and natural senescence, and accumulates 7-HMC a and pheophorbide a (Pheo a) in green leaf blades. Interestingly, both rice and Arabidopsis hcar mutants exhibit severe cell death at the vegetative stage; this cell death largely occurs in a light intensity-dependent manner. In addition, 7-HMC a treatment led to the generation of singlet oxygen ($^1O_2$) in Arabidopsis and rice protoplasts in the light. Under herbicide-induced oxidative stress conditions, leaf necrosis was more severe in hcar plants than in wild type, and HCAR-overexpressing plants were more tolerant to reactive oxygen species than wild type. Therefore, in addition to functioning in the conversion of 7-HMC a to Chl a in senescent leaves, HCAR may play a critical role in protecting plants from high light-induced damage by preventing the accumulation of 7-HMC a and Pheo a in developing and mature leaves at the vegetative stage.

• 한국식품조리과학회지
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• 제33권3호
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• pp.275-284
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• 2017

Purpose: This study was performed to evaluate the effects of sannamul or herb extract addition to a soybean oil-in-water emulsion during photooxidation in the presence of chlorophyll. Methods: The emulsion mainly consisted of purified soybean oil and citric acid buffer (pH 4.0) at a weight ratio of 4 to 6, with chlorophyll a addition at 6 mg/kg. Ethanol extract of daraesoon, samnamul, basil, or peppermint was selectively added to the emulsion at 400 mg/kg, and emulsions in glass serum bottles were oxidized at $5^{\circ}C$ under 2,600 lux light for 48 hours. Lipid oxidation of the emulsions was evaluated based on determination of headspace oxygen content, peroxide value, and p-anisidine value. Pigments and antioxidants were also monitored. Results: The emulsion with added samnamul extract with high contents of polyphenols and low chlorophyll content showed lower oxygen consumption, peroxide values, and p-anisidine values, whereas basil and peppermint extracts with high chlorophyll contents increased photooxidation. Chlorophylls were degraded during photooxidation of the emulsions, and the degradation rate was highest in the emulsion with added samnamul extract. Conclusion: The high antioxidant activity of samnamul extract in the photooxidation of soybean oil-in-water emulsion could be due to low chlorophyll content, high concentrations of polyphenol compounds in the extract, as well as rapid degradation of chlorophylls during oxidation.

• 한국식품조리과학회지
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• 제29권1호
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• pp.53-62
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• 2013

Lipid oxidation and antioxidants changes in perilla oil emulsion added with chlorophyll were studied during storage in the dark or under 1,700 lux light at $25^{\circ}C$ for 48 h. The emulsion was consisted of perilla oil (33.12 g), 5% acetic acid (66.23 g), egg yolk powder (0.5 g), and xanthan gum (0.15 g), and Chlorophyll b was added to the emulsion at 0, 2.5 and 4 mg/kg. The lipid oxidation was evaluated by headspace oxygen consumption and hydroperoxide formation, and tocopherols and polyphenols were monitored by HPLC and spectrophotometry at 725 nm, respectively. The lipid oxidation of the perilla oil emulsion in the dark was not significant regardless of the addition of chlorophyll. Light increased and accelerated the lipid oxidation of the emulsion, and increased addition level of chlorophyll under light increased it further. However, there was no significant change in fatty acid composition in any case. Contents of tocopherols and polyphenols in the emulsion were not significantly changed during storage in the dark regardless of chlorophyll addition, indicating their little degradation. Tocopherols and polyphenols in the emulsion were significantly degraded during storage of the emulsion under light, and the degradation rate of polyphenols was increased with addition level of chlorophyll. The lipid oxidation of the perilla oil emulsion was inversely related with the residual amounts of tocopherols and polyphenols, with more dependent on the retention of polyphenols than that of tocopherols.