• 한국토양비료학회지
• /
• 제37권5호
• /
• pp.341-349
• /
• 2004

오이와 방울토마토에 Glomus sp.를 종자파종과 고형배지경에 정식시 각각 접종하여 생장과 수량반응 및 균근 감염 양상 등을 비교 검토하였다. 오이와 방울토마토의 초장, 엽수, 엽면적 및 건물중 등의 전반적인 생장은 무접종 < 정식시 균근균 접종 < 파종시 균근균 접종의 순으로 양호하였으며, 과실수량반응은 종자파종시에 균근균을 접종할 경우 과실의 생체중이 가장 높게 나타났고, 과실의 당도도 증가하였다. 균근감염은 오이와 방울토마토 모두 주로 균사에 의하여 이루어 졌고. vesicle와 arbuscule에 의한 감염은 극히 적었다. 뿌리체내 균근균 감염율은 종자파종시 균근균 접종원 처리의 경우가 정식시에 균근균 접종원을 처리한 경우보다 높았다. 균근균 접종에 따른 과실 수확을 보면 오이의 경우 주당 과실수가 증가하였고, 토마토의 경우 주당 과실의 수확 중량이 증가하였다.

• The Plant Pathology Journal
• /
• 제34권2호
• /
• pp.113-120
• /
• 2018

Chlorella, one single-cell green algae organism that lives autotrophically by photosynthesis, can directly suppress some plant diseases. The objective of this study was to determine whether pre-spraying with Chlorella fusca suspension could induce systemic acquired resistance (SAR) in cucumber plants against anthracnose caused by Colletotrichum orbiculare. In order to illustrate SAR induced by algae, infection structures in host cells were observed under a transmission electron microscope (TEM). Cytological changes as defense responses of host mesophyll cells such as accumulation of vesicles, formation of sheath around penetration hyphae, and thickness of cell wells adjoining with intracellular hyphae were demonstrated in cucumber leaves. Similar defense responses were also found in the plant pre-treated with DL-3-aminobutyric acid, another SAR priming agent. Images showed that defense response of host cells was scarcely observed in untreated leaf tissues. These cytological observations suggest that C. fusca could induce SAR against anthracnose in cucumber plants by activating defense responses of host cells.

• The Plant Pathology Journal
• /
• 제27권1호
• /
• pp.8-13
• /
• 2011

The induced resistance of cucumber leaves treated with oligochitosan to the infection of the cucumber powdery mildew, Sphaerotheca fuliginea, was investigated using transmission electron microscopy. The results showed that when the plants were treated with oligochitosan and challenged with inoculum, a significant decrease of the disease occurred. The mycelial development in the treated leaves was markedly inhibited. The cytoplasm of the powdery mildew mycelium was aggregated, with its organelles disintegrated and the cytoplasm collapsed. The protoplasm in haustoria became electron-dense. Haustoria became malformed, their organelles disintegrated, the hausterial wall thickened and eventually the whole complex necrotized. The host cells produced defence structures and materials associated with infection and a hypersensitive response. The host cell wall was thickened and deeply stained; several layers of papilla structure were produced under the cell wall; dark materials were deposited between the cell wall and plasmalemma; extrahaustorial plasmalemma was deeply stained and extrahaustorial matrix appositions had large deposits of electron-dense material; the cytoplasm was disordered, host organelles disintegrated and eventually the whole host cell disintegrated and necrotized.

• The Plant Pathology Journal
• /
• 제20권3호
• /
• pp.172-176
• /
• 2004

Bacterial isolates TRL2-3 and TRK2-2 showing anti-fungal activity in vitro test against some plant pathogens were identified as Pseudomonas putida and Micrococcus luteus, respectively. Pre-treatment with both bacterial isolates at the concentration 1.0$\times$ $10^7$ and $10^6$cfu/ml in the rhizosphere could trigger induced systemic resistance in the aerial part of cucumber plants against anthracnose caused by Colletotrichum orbiculare. However, the pre-treatment with the higher concentration at 1.0 $\times$ $10^8$ cfu/ml of both isolates could not induce resistance after challenge inoculation with C. orbiculare. As a positive control, the treatment with DL-3 amino butyric acid caused a remarkable reduction of disease severity whereas the lesions on the leaves of untreated plants developed apparently after the fungal inoculation. From these results, it was recomended that disease control using both bacterial isolates inducing systemic resistance in the field where chemical application is forbid.

• The Plant Pathology Journal
• /
• 제22권2호
• /
• pp.131-138
• /
• 2006

Two strains of Cucumber mosaic virus (CMV) isolated in Kuwait were confirmed their infectivity based on symptomatology and host range on different cultivars of tomato (Lycopersicon esculentum), tobacco(Nicotiana tabacum L.) and squash (Cucurbita pepo). The pattern of symptoms differed for the two CMV strains in tomato and tobacco, showing severe stunting and mosaic symptoms with one strain designated KU2, and almost symptomless with the other strain designated KU1. A satellite RNA 5 (sat-RNA) was found to be associated with the KU1 strain and was characterized as a benign viral satellite RNA. Using reverse transcription and polymerase chain reaction (RT-PCR) with sat-RNA specific primers, an amplified PCR product of about 160bp was determined and analyzed by gel electrophoresis. This naturally occurring benign viral satellite RNA was successfully used as a biological control agent to protect tomato plants against the severe KU2 strain. Tomato plants grown in plant-growth chambers, were preinoculated with KU1 containing the benign viral satellite and then challenge inoculated with the severe KU2 strain at different time intervals. All plants challenged three weeks after preinoculation showed nearly complete protection from subsequent infection by the severe strain. This biological control technology using plant viruses was found protective and could be successfully established sooner after the preinoculation.

• 한국유기농업학회지
• /
• 제7권1호
• /
• pp.105-113
• /
• 1998

수종의 근권세균이 양액재배 오이의 생장에 미치는 영향을 구명하기 위하여 Azospirillum sp., Rhodopseudomonas sp., Pseudomonas sp., Bacillus sp.와 Corynebacterium glutamicum간의 융합균주 등을 근권처리하였다. 융합균주의 근권처리후 4일에 세균의 밀도변화르르 보면 코코피트 > 암면 > 배양액 등의 순으로 나타났다. 균주의 근권처리에 따른 오이의 생장촉진효과는 암면경보다 코코피트경에서 더 높았으며, 균주의 종류별 오이의 생장촉진효과를 보면 Azospirillum sp. > 광합성세균 $\ge$ 융합균주 Pseudomonas sp. > 대조구 등의 순으로 나타났다.

• 생명과학회지
• /
• 제8권3호
• /
• pp.272-278
• /
• 1998

UV-B 강도 변화가 식물의 생장에 미치는 영향을 조사하기 위하여, 오이를 이용하여 3주간 3단계의 UV-B[일일 평균 UV-$B^{BE}$; 무처리(0.03), 저UV-B(6.40), 고UV-B(11.32) kJ $m^{-2}$]조사 실험을 수행하였다. 3주간의 UV-B 조사에 의해 건물중 및 엽면적은 고UV-B 처리와 저UV-B 처리에서 각각 60%와 40% 정도의 감소를 보였으나, 엽중비는 증가하였다. UV-B에 의해 고UV-B 처리에서 약 45%, 저UV-B 처리에서 약 37%의 광합성속도의 감소를 나타내었으나 증산속도의 변환느 나타나지 않았다. 총 엽록소 함량은 UV-B 강도의 증가에 따라 감소하였으며, UV-흡수물질인 flavonoid의 함량은 고UV-B 처리에서 약 19% 저UV-B처리에서 약 14%의 증가를 보였다. 이상의 결과로 볼 때 UV-B조사는 오이 식물에 극심한 생육 저해를 나타내었으며, 그 피해는 UV-B 강도에 따라 증가하였다. 따라서 현재 지구에 도달하는 태양UV-B에 의해서도 오이식물은 영향을 받고 있는 것으로 사료되며, 장래 예상되는 오존층 감소에 의해서도 생육장해를 나타낼 것으로 사료된다.

• Journal of Applied Biological Chemistry
• /
• 제52권4호
• /
• pp.195-199
• /
• 2009

현재 산업적으로 여러 가지 용도로 사용되고 있는 계면활성제 중에서 임의로 선택한 비이온성 계면활성제와 음이온성 계면활성제 수용액을 온실 내에서 자연적으로 흰가루병 발생을 유도한 성체 오이에 분무 살포한 후 병 방제효과를 측정함으로써 약해 유발이 없으면서 병 방제 효과가 우수한 계면활성제를 선발하였다. 이 계면활성제 수용액을 DBEDC 희석액과 혼합처리하여 흰가루병에 대한 방제력의 변화를 조사함으로써 합제개발의 가능성을 시험하였다. 시험한 20종의 계면활성제 중에서 pentaetylene glycol monododecyl ether, pentaethylene glycol monodecyl ether와 pentaethylene monododecyl ether의 혼합물 및 pentaethylene glycol mono-9-octadecenyl ether 등이 약해를 거의 유발하지 않으면서 흰가루병에 대한 높은 방제 효과를 보였는데, 그 효과는 fenarimol 유제보다 우수하거나 대등한 것으로 나타났다. 이중 pentaethylene glycol monododecyl ether는 예방효과가 우수한 DBEDC와 혼합처리 하였을 때 서로 상가적으로 작용하여 현저하게 높은 방제 효과를 나타내었다.

• 한국환경과학회지
• /
• 제21권12호
• /
• pp.1435-1447
• /
• 2012

The present study was conducted to determine the effect of hexaconazole (HEX), a triazole fungicide, on the growth, yield, photosynthetic response and antioxidant potential in cucumber (Cucumis sativus L.) plants subjected to UV-B stress. UV-B radiation and HEX were applied separately or in combination to cucumber seedlings. The growth parameters were significantly reduced under UV-B treatment, however, this growth inhibition was less in HEX treated plants. HEX caused noticeable changes in plant morphology such as reduced shoot length and leaf area, and increased leaf thickness. HEX was quite persistent in inhibiting shoot growth by causing a reduction in shoot fresh and dry weight. HEX noticeably recovered the UV-B induced inhibition of biomass production. Significant accumutation in anthocyanin and flavonoid pigments in the leaves occurred as a result of HEX or UV-B treatments. HEX permitted the survival of more green leaf tissue preventing chlorophyll content reduction and higher quantum yield for photosystemII under UV-B exposure. HEX treatment induced a transient rise in ABA levels in the leaves, and combined application of HEX and UV-B showed a significant enhancement of ABA content which activates $H_2O_2$ generation. UV-B exposure induced accumulation of $H_2O_2$ in the leaves, while HEX prevented UV-B induced increase in $H_2O_2$, indicating that HEX serves as an antioxidant agent able to scavenge $H_2O$ to protect cells from oxidative damage. An increase in the ascorbic acid was observed in the HEX treated cucumber leaves affecting many enzyme activities by removing $H_2O_2$ during photosynthetic processes. The activities of antioxidant enzymes including catalase(CAT), ascorbate peroxidase(APX), superoxide dismutase(SOD) and peroxidase(POD) in the leaves in the presence of HEX under UV-B stress were higher than those under UV-B stress alone. These findings suggest that HEX may participate in the enhanced tolerance to oxidative stress. From these results it can be concluded that HEX moderately ameliolate the effect of UV-B stress in cucumber by improving the components of antioxidant defense system.

• 한국식물병리학회지
• /
• 제14권3호
• /
• pp.220-222
• /
• 1998

In 1995, we collected stock (Matthiola incana) plants causing mosaic symptoms on leaves and color breakings on flowers in Daekwallyong, Korea. Two viruses were isolated from the infected plants, and identified as cucumber mosaic virus (CMV) and turnip mosaic virus (TuMV) by experiments of host range, serology and electron microscopy. Each of the virus did not produce the same symptoms on the stock seedlings as naturally infected plants caused. When the viruses were coinoculated to the stock seedlings, however, severe mosaic symptoms were observed on leaves, and then the color breakings were expressed on flowers.