Acidic soil significantly reduces crop productivity mainly due to aluminum (Al) toxicity. Alfalfa (Medicago sativa L.) roots were exposed to aluminum stress (Al3 +) in calcium chloride (CaCl2) solution (pH4.5) and root growth, physiological and antioxidant enzyme responses were investigated. The root growth (length) was significantly inhibited after 48 h of aluminum stress imposition. Histochemical staining with hematoxylin indicated significant accumulation of aluminum in Al stress-treated root tissues. Histochemical assay were also performed to detect superoxide anion, hydrogen peroxide and lipid peroxidation, which were found to be more in root tissues treated with higher aluminum concentrations. The enzymatic activity of CAT, POD and GR in root tissues was slightly increased after Al stress treatment. The result suggests that Al stress alters root growth in alfalfa and induces reactive oxygen species (ROS) production, and demonstrates that antioxidant enzymes involved in detoxification of Al-mediated oxidative stress.

Phytoextraction은 식물을 이용하여 환경 정화하는 기술로서 금속으로 오염된 토양을 정화하는 것이다. 토양에 존재하는 금속의 추출을 용이 하기 위해서 현재 다양한 킬레이트가 사용되고 있다. Phytoextraction이 경제적이고 친환경적인 장점이 있지만 고농도로 오염된 지역에서는 적용이 어려운데 이는 식물이 이러한 지역에서 살아남기 어렵기 때문이며 이러한 문제점을 해결하는 것이 본 연구의 목적이다. 연구 대상의 금속으로서 수은을 선택하였고, 킬레이트는 아미노산인 시스테인과 히스티딘, 작은 크기의 유기산으로서 citric acid, malic acid, succinic acid, oxalic acid, 그리고 ethylenediamine (EDA)를 선택하였으며, EDTA는 비교 대상으로 본 연구에 사용되었다. 다양한 농도의 수은을 포함하는 배지에 식물을 키우면서 여러 킬레이트가 식물의 뿌리 성장에 미치는 영향을 분석하였다. 수은에 의한 식물의 성장 억제는 시스테인과 EDA에 의해서 완화되었으며 히스티딘과 citrate는 별 다른 영향이 없었다. Malate, succinate, 그리고 oxalate는 수은에 의한 식물 성장 억제를 더 촉진시켰다. 따라서 수은의 식물성장억제를 완화시켜주는 시스테인과 EDA는 고농도의 수은으로 오염된 지역에서 식물의 성장이 가능하도록 유용하게 사용될 수 있을 것이다.

Angelica tenuissima, also known as Ligusticum tenuissimum, is classified as a food-related plant and has been used as traditional medicines treating headache and anemia in Asia. However, its anti-melanogenic effect has not been reported in detail. When the extract of Angelica tenuissima (ATE) was prepared by the extraction with 70% EtOH at 80°C (final yield = 22%), the contents of decursin and Z-ligustilide in ATE were determined 0.06% and 8.43%, respectively. Total flavonoid and phenolic content in mg ATE were 5.52±0.07 ㎍ quercetin equivalents and 237.27±13.24 ㎍ gallic acid equivalents, respectively. Antioxidant capacity of ATE determined by DPPH and ABTS assay was increased with a dose dependent manner up to 1000 ㎍/㎖. The amount of melanin synthesis followed by α-melanocyte stimulating hormone on B16F10 cells were significantly reduced in the presence of ATE (250 to 1000 ㎍/㎖, p<0.05). ATE (125 to 1000 ㎍/㎖, p<0.05) suppressed the tyrosinase activity but did not show any significant effect on α-glucosidase activity at the same condition. Taken together, ATE possesses tyrosinase inhibitory potential with significant antioxidant capacities. These effects of ATE might be involved in suppression of melanin synthesis, at least, in B16F10 cells. The anti-melanogenic potential of ATE will provide an insight into developing a new skin whitening product.

전 세계적인 지구 온난화로 인한 가뭄은 농작물의 생산성을 저해하는 주요 원인 중 하나이며, 고온과 건조가 복합적으로 작용하여 식물 생장을 감소시킨다. 본 연구에서는 Bacillus velezensis YP2 균주의 식물 생육촉진 및 건조 스트레스 내성 증진 효과를 온실과 시설하우스 포장에서 조사하였다. 또한 B. velezensis YP2 균주의 처리 전과 후 케일 근권과 뿌리에서 배양법에 의한 상대 정량 방법으로 B. velezensis YP2 균주의 근권 및 뿌리 정착능을 분석하였다. 온실 검정 결과 YP2 균주 처리구에서는 무처리구와 비교하여 케일 유묘의 초장 26.7% 및 지상부 생체중 142.2% 증가시키는 효과가 있었다. 또한 B. velezensis YP2 처리구에서는 무처리구와 비교하여 39.4%의 건조 피해 경감 효과가 있었다. 시설하우스 포장 검정 결과에서도 B. velezensis YP2 균주 처리에 의한 케일의 생장촉진 효과와 건조 스트레스 내성 증진 효과가 있었으며, B. velezensis YP2 처리구에서 케일 잎의 상대수분함량이 무처리구와 비교하여 7, 10, 14일에 모두 높은 것으로 나타났다. B. velezensis YP2 균주의 뿌리 정착능 분석 결과, 균주 처리 21일까지 케일 근권 및 뿌리 균밀도가 무처리구와 비교하여 B. velezensis YP2 처리구에서 유의하게 높은 것으로 나타났다. 따라서 균주 처리 후 최소한 21일이 경과할 때까지 B. velezensis YP2 균주가 케일 근권과 뿌리에 정착하여 식물과 상호작용함으로서 생육을 촉진하고 식물의 물 이용률을 증가시켜 건조 스트레스 내성을 증진하는 데 관련이 있을 것으로 판단된다. 본 연구 결과를 통하여 B. velezensis YP2 균주는 가뭄으로 인한 건조한 토양 조건에서 작물 생산성을 향상시키는 가능성이 있는 유용한 미생물로 이용할 수 있을 것으로 생각된다.

When three cultivars, “Shinsunchalbyeo”, “Nokmi” and “GW-05-01”, which was collected from native glutinous rice, were exposed to increased salinity stress in exogenous solution and duration of salt stress, leaf relative water content (RWC), root water uptake and chlorophyll fluorescence were observed the significant decrease at ≥500mM NaCl concentration for 4 day stress. These decrease in leaf RWC showed 69%, 77% and 67% for Shinsunchalbeyo, Nokmi and GW-05-01, respectively, in water uptake these effects showed 84%, 85% and 91%. The difference in Fv/Fm of plants treated with 500mM NaCl showed 0.62, 0.68 and 0.78 compared with 0.78, 0.81 and 0.75 in control treatment. The effects of NaCl stress in rice seedlings indicate that the leaf RWC and photosynthetic capacity is more sensitive GW-05-01 in comparison with Shinsunchalbyeo and Nokmi, and water uptake in root is more resistant. Average plant height in Shisunchalbyeo, Nokmi and GW-05-01 showed 107, 102 and 111cm, and the 1000 grains weight were 25.5, 20.3 and 21.8, respectively.

Development of shoot and root, leaf water potential and photosynthetic rate affected by water stress in early growing stage of tobacco were surveyed to interpret stress response in terms of plant physiological and agricultural aspects. The growth of shoot and root was highly suppressed by water stress and the difference in dry weight by rewatering was smaller in root than in shoot. The total root length was highly decreased by water stress and the lengths of root for water stress and non-stress were 74m and 84m, respectively, after rewatering. The root growth treated by water stress was increased between 2nd and 3rd day after treatment indicating that temporary water stress at early growing stage might have increased of root zone activity for early growth stage. The leaf water potentials were decreased to -7.63MPa, -9.47MPa, -11.89MPa, -13MPa at the 2nd, 3rd, 4th and 5th day by water stress. The relative water contents were 75%, 62% and 57% at the 3rd, 4th and 5th day after treatment. Photosynthesis was reduced largely by water stress. The photosynthetic rate after treatment at 2nd day and 3rd day was dropped to 18.15~mu mol. CO2 /m2 ㆍsec-1 and 9.35~mu mol. CO2 /m2 ㆍsec-1 . It was never recovered to the normal, even after rewatering. Stomatal conductance had been reduced since 2nd day after treatment and increased after rewatering.