Environmental Adaptability of Eupatorium rugosum : Relationship between Accumulation of Heavy Metals and Phenolic Compounds

Seed germination rate and seedling growth were measured on 6 different species(Phytolacca americana, Eupatorium rugosum, Rumex acetocella, Echinochloa crusgalli, Cassia mimosoides var. nomame, Setaria viridis) treated with leaf extract of E. rugosum. Total phenolic compound and heavy metal were analyzed on leaf and soil with and without E. rugosum. The growth of P. americana seedlings were stimulated by 10% and 25% of E. rugosum water extract treatment. The content of total phenolic compounds in soil was lower than that of leaf extract, and 25% was confirmed as threshold concentration in natural systems because the total phenolic compounds were not significantly different between the control soils and the soil treated with 10%, and 25% extract. Total phenolic compound concentrations of the leaf extracts were highest (1.66 mg/l) with E. rugosum grown under the Quercus forest canopy and lowest (1.09 mg/l) for the plant grown in the mixed forest edge. Leaf extracts of plants selected in different sampling sites (Forest interior, Forest edge, under Pinus Canopy and Quercus Canopy) were significant, while soil extracts were not. Seed germination of R. acetocella and S. viridis were significantly inhibited at over 50% concentrations of E. rugosum, but C. mimosoides var. nomame was not affected at any concentration. The radicle and shoot growth of the native species group were reduced two times more than those of the exotic species group by the treatment of extracts. Especially, the seed germination percentage and dry weight of E. rugosum were greater than those of the control group by treatments with extracts of 10% and 25%. Analysis of aqueous extracts from E. rugosum by HPLC identified 6 phenolic compounds: caffeic acid (460.9 mg/l), benzoic acid (109.7 mg/l), protocatechuic acid (7.3 mg/l), ρ-hydroquinone (6.0 mg/l), cinnamic acid (2.7 mg/l) and hydroquinone (0.23 mg/l). The seed germination of P. americana was also inhibited dramatically by protocatechuic acid and cinnamic acid even though the content of caffeic acid (460.9 mg/l) was the highest among analyzed phenolic compounds. The heavy metal content of soil without A. altissima was higher than that of soil with E. rugosum. Particularly, Al, Fe and Mn was considerably high and most of the heavy metal were accumulated in leaves where a high level of total phenolic compounds was found.

서양등골나물의 환경적응력 : 중금속 축적과 Phenolic Compounds의 관계

서양등골나물의 잎 추출액을 미국자리공을 비롯한 5종의 식물에 처리하여 종자발아와 유식물생장을 조사하였고, total phenolic compounds와 중금속 이온을 서양등골나물의 분포에 따라 잎과 토양에서 분석하였다. 서양등골나물의 잎 추출액에 의한 미국자리공의 초기생장은 10%와 25%농도에서 촉진되었고, 토양 추출액의 total phenolic compounds는 잎 추출액의 total phenolic compound 보다 낮았다. 토양의 total phenolic compounds는 대조구와 10%, 25% 농도로 처리된 토양에서 유의한 차이가 없었으며 자연상태에서 잎 추출액 25%가 threshold 농도임을 확인하였다. 서양등골나물의 total phenolic compounds는 신갈나무림 임상에서 1.66 mg/1, 임연에서는 1.09 mg/l로 조사되었으므로 상부식생에 따른 total phenolic compounds는 유의한 차이를 보였으나, 각 토양에서는 상부식생에 따라 total phenolic compounds간에 유의한 차이를 보이지 않았다. 서양등골나 물의 잎 추출액 처리시 애기수영과 강아지풀의 발아율은 50% 이상의 농도에서 현저히 억제되었으나, 차풀의 발아율은 추출액의 농도에 따라 차이가 없었다. 유묘와 유근생장은 귀화종 그룹보다 자생종 그룹이 2배 이상 억제되었으며, 특히 서양등골나물의 추출액 농도 10%와 25%가 처리된 서양등골나물의 종자발아와 건중량은 대조구보다 촉진되었다. 서양등골나물의 phenolic compounds를 HPLC로 분석한 결과 caffeic acid (460.9 mg/1), benzoic acid (109.7 mg/l), protocatechuic acid (7.3 mg/l), ρ-hydroquinone (6.0 mg/l), cinnamic acid (2.7 mg/l), hydroquinone (0.23 mg/1) 순으로 분석되었다. 분석된 서양등골나물의 phenolic compounds 각각에 대한 미국자리공의 발아율은 caffeic acid (460.9 mg/l)치 농도가 높을지라도 이것이 낮은 cinnamic acid와 protocatechuic acid에서 현저한 억제현상을 보였다. 서양등골나물 임상의 토양보다 서양등골나물이 분포하지 않는 토양의 중금속 함량이 전반적으로 높았다. 특히 Al, Fe 및 Mn의 함량이 높았으며 이들 중금속은 total phenolic compound 함량이 높은 잎에 대부분이 축적되었다.