• The Plant Pathology Journal
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• 제34권1호
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• pp.1-10
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• 2018

A previously unreported bacterial disease on chili pepper (Capsicum annuum L.) seedlings affecting as many as 4% of seedlings was observed in greenhouses in Chihuahua, Mexico (Delicias and Meoqui counties). Initial lesions appeared as irregular small spots on leaves and brown necrosis at margins tips were observed. Later, the spots became necrotic with a chlorotic halo. Advanced disease was associated with defoliation. A Gram negative, rod-shaped bacterium was isolated from diseased chili pepper seedlings. Three inoculation methods revealed that isolated strains produce foliage symptoms, similar to those observed in naturally infected seedlings. Pathogenic strains that caused symptoms in inoculated seedlings were re-isolated and identified to fulfill koch's postulate. Polyphasic approaches for identification including biochemical assays (API 20E and 50CH), carbon source utilization profiling (Biolog) and 16S rDNA, hsp60 and rpoB sequence analysis were done. Enterobacter cloacae was identified as the causal agent of this outbreak on chili pepper seedlings.

• 한국유기농업학회지
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• 제6권1호
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• pp.109-116
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• 1997

This experiment was carried out to examine the effect of various functional materials such as bioceramic podwers, crushed shells and elvanites supplemented to the each substrate on the seedlings growth of cucumber, watermelon and tomato. The seedlings were grown in pots filled with substrates of bioceramic podwers, crushed shell and elvanites. The growth of cucumber seedlings in terms of plant height, stem diameter, leaf width, leaf area, plant fresh and dry weight was promoted by adding the bioceramic. powder (1 to 2g/kg), crushed shells (20 to 80g/kg) or elvanites (20 to 80g/kg). Watermelon seedlings in terms of plant height, number of leaves and leaf area were greater than those of the control by adding bioceramics (1 to 2g/kg). Plant height was also promoted by the adding of bioceramic power from 16 days after treatment. But leaf area was increased from 8 days after treatment, while stem diameter was not affected. Watermelon seedlings were also influenced by adding curshed shells (20 to 80g/kg) and elvanites (20 to 40g/kg) into each substrate. The growth of characteristics of tomato seedlings were promoted by adding 1 to 3g/kg of bioceramics, 10 to 80g/kg of crushed shell or 20 to 40g/kg of elvanites, respectively. Especially, root growth was greatly influenced by bioceramic powder, whereas the shoot growth(leaves and stem) was stimulated by crushed shells and elvanites suppemented into substrate.

• Journal of Microbiology
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• 제45권1호
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• pp.15-20
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• 2007

The majority of soil microorganisms can derive ethylene from L-methionine (L-MET), while some rhizobacteria can hydrolyze 1-aminocyclopropane-1-carboxylate (ACC) due to their ACC-deaminase activity. In this study, three strains having either ACC-deaminase activity (Pseudomonas putida biotype A, $A_7$), or the ability to produce ethylene from L-MET (Acinetobacter calcoaceticus, $M_9$) or both (Pseudomonas fluorescens, $AM_3$) were used for inoculation. The highly ethylene specific bioassay of a classical 'triple' response in pea seedlings was used to investigate the effect of the inoculation with the rhizobacteria in the presence of 10 mM ACC or L-MET. The exogenous application of ACC had a concentration-dependent effect on the etiolated pea seedlings in creating the classical 'triple' response. The inoculation with P. putida diluted the effect of ACC, which was most likely due to its ACC-deaminase activity. Similarly, the application of $Co^{2+}$ reduced the ACC-imposed effect on etiolated pea seedlings. In contrast, the inoculation of A. calcoaceticus or P. fluorescens in the presence of L-MET caused a stronger classical 'triple' response in etiolated pea seedlings; most likely by producing ethylene from L-MET. This is the first study, to our knowledge, reporting on the comparative effect of rhizobacteria capable of utilizing ACC vs L-MET on etiolated pea seedlings.

• 한국작물학회지
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• 제51권4호
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• pp.322-328
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• 2006

A series of methanol extracts from leaf and root parts in spring- and winter-barley plants were assayed to determine their allelopathy and antioxidant activity. The methanol extracts applied on filter paper in a Petri-dish significantly inhibited root growth of Chinese milkvetch (Astragalus sinicus L.) seedlings. Leaf extracts at 25 and 50 g $L^{-1}$ inhibited root growth of Chinese milkvetch seedlings more than root extracts. No difference in phytotoxic effects of spring- and winter-barley seedlings extracts on root growth of Chinese milkvetch was observed. Methanol extracts dose-dependently increased DPPH free radical scavenging activity in vitro. DPPH free radical scavenging activity was higher in the methanol extracts from winter-barley seedlings than in those from spring-barley seedlings, and from leaf extracts than from root extracts. The antioxidant potential of the individual fraction from the methanol extracts of spring-barley seedlings was in order of n-butanol>ethyl acetate>water>chloroform>n-hexane fraction. By means of HPLC analysis, spring-barley (200.62 mg $100g^{-1}$) had more amount of total phenol acid than winter-barley (114.08 mg $100g^{-1}$). Especially, ferulic acid was detected in spring-barley extract (183.46 mg $100g^{-1}$) as the greatest amount. These results suggest that early seedlings of barley plants had potent allelopathy and antioxidant activity, and their activities were differently exhibited depending on plant parts and growing condition.

• 생물환경조절학회지
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• 제15권1호
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• pp.100-106
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• 2006

A hypertonic solution of sorbitol was used to precondition Douglas-fir and Western hemlock plug seedlings to improve desiccation resistance. Seedlings were preconditioned by soaking their root balls in water, -0.75 or -1.50 MPa sorbitol solution for 22 hr, and then exposed to desiccation conditions for 8 days. During the desiccation period, a transpirational water loss was significantly reduced by the sorbitol preconditioning, with its effect positively depending on concentration. This preconditioning-induced reduction in water loss was mainly caused by the decline in needle stomatal conductance. Sorbitol-induced stomatal control was more closely associated with reduction in plant water potential, rather than increase in abscisic acid concentrations. After rehydration of stressed-plants, most of the preconditioned seedlings with sorbitol were survived, while only 35% of Douglas-fir and 28% of Western hemlock seedlings treated with water were alive. The post-growth was significantly greater in the preconditioned seedlings than only water-treated seedlings. These results suggested that the earlier stomatal control with sorbitol-facilitated preconditioning could play a role in improving desiccation resistance of evergreen woody plants at transplanting in the field where water supply is limited or dry conditions are prevailing.

• 한국자원식물학회지
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• 제27권6호
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• pp.629-634
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• 2014

Rice type tartary buckwheat is used as a substitute for rice in many Asian countries due to its easy dehulling character. The objective of the present study was to determine the chlorophyll, total polyphenol (TP), total flavonoid (TF), antioxidant activity and to quantify the bioactive compounds rutin, quercetin and chlorogenic acid in the seedlings of rice-type tartary buckwheat (RTTB). Young seedlings exhibited higher antioxidant (DPPH radical inhibition) activity in dose dependent manner. TP and TF content were highest ($3017.46{\pm}201.84{\mu}g$ TAE/100 mg dw and $1916.0{\pm}102.95{\mu}g$ QE/100 mg dw respectively) in 3 days after germination (DAG) seedlings compare to 6 and 9 DAG. The contents of rutin and quercetin increased with growing stage of seedlings. However, the chlorogenic acid decreased with increasing growth. Overall, RTTB seedlings can be regarded as a strong source of phenolics and have high possibility for food and nutraceutical application due to their efficient antioxidant properties, higher chlorophyll and phytochemical content.

• 임산에너지
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• 제21권3호
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• pp.28-33
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• 2002

본 연구는 우량 층층나무 용기묘 생산기술을 개발하기 위하여 5개월간 비닐온실에서 수행되었다. 공시용기로 사용된 플라스틱 망 용기와 일반 플라스틱 용기에서 생육한 묘목의 수고생장 차이는 없었으나, 근원경생장은 플라스틱 망 용기에서 높게 나타났다. 플라스틱 망 용기에서 생육한 묘목은 장근 및 세근발달이 촉진되었으며, 지상부와 지하부 건물생산량이 뚜렷하게 증가하였다. 특히 플라스틱 망 용기에서 생육한 묘목에서는 망 용기에 의해 유도된 공기단근에 의하여 나선형 뿌리가 나타나지 않았다. 본 실험에서 사용된 플라스틱 망 용기는 묘목의 뿌리발달을 좋게하며 지상부 생장이 향상된 층층나무 용기묘 생산에 유용한 것으로 판단된다.

• Journal of Biosystems Engineering
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• 제14권3호
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• pp.181-187
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• 1989

The mechanical and rheological properties of agricultural materials which influence the machine design or handling are not completely understood. Agricultural materials do not react in a purely elastic manner, and their responses when subjected to stress and strain appear a combination of elastic and viscous behavior. Many researchers have studied the mechanical and rheological properties of the various agricultural materials, but those properties are available mostly for foreign varieties of agricultural products. Rheological properties of rice seedlings become important to formulate the principles governing their mechanical behavior. The objectives of this study were to experimentally determine the creep and recovery behavior of rice seedlings of one japonica-type and one Indica x japonica hybrid in the transplanting age. The results of this study are summarized as follows; 1. The compression creep and recovery behavior of mat-type seedlings could be described by 4-element Burger's model. 2. The steady-state creep appeared at the stress larger than 0.8 MPa and the logarithmic creep appeared at the stress smaller than 0.8 MPa. 3. In the compression creep test of the rice seedlings, the instantaneous elastic modulus of Burger's model showed the range from 20 to 40 MPa. The higher value of absolute viscosity for the rice seedling explained that the rice seedlings were viscoelastic materials. 4. In the recovery test of the rice seedlings, there was a tendency that the higher permanent strain of all samples was observed under the smaller stress being appeared, and the larger permanent strain in Dongjin was observed than in Samkang.

• 생물환경조절학회지
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• 제12권4호
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• pp.259-265
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• 2003

오이, 토마토 고추 작물의 고온기 플러그 육묘시 묘의 도장 방지와 과번무 억제를 위한 UV-B와 생장 억제제의 처리가 플러그묘 식물체의 생리적 특성 변화와 항산화 효소의 활성에 미치는 영향을 조사하였다. 광합성능력은 UV-B 처리묘의 경우 무처리에 비해 처리 직후에는 크게 떨어졌으나 10일 후에는 비스하게 회복되었고 생장억제제 처리묘는 무처리에 비해 토마토가 다소 떨어졌어나 오이와 고추는 비슷하였다. 엽록소함량은 3작물 모두 처리간에 유의한 차이가 없었다. 안토시아닌 함량은 무처리에 비해 UV-B 처리한 것이 다소 높았던 반면 생장억제제 처리한 것은 무처리와 비슷하였다. SOD, CAT, POD 등의 항산화효소의 활성은 3작물 모두 UV-B 처리한 것이 가장 높았으며, 처리 직후에는 크게 증가되었다가 10일 후에는 그 절반 이하로 감소하였다. 한편 생장억제제 처리묘는 무처리에 비해서 항산화 효소의 활성이 다소 높았으나 UV-B 처리묘에 비해서는 낮았다.

• 원예과학기술지
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• 제28권5호
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• pp.810-817
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• 2010

본 실험은 4배체 포도의 방임수분과 인공수분으로부터 획득된 실생으로부터 이상자엽의 형태적 특성을 조사하였고, 특히 이들 이상자엽 실생으로부터 저 고4배 식물을 선발하였다. 이상자엽은 크게 5 형태로 구분되었다. 4배체 4품종의 방임수분 실생에서 이상자엽의 발생빈도는 1.6%로 조사되었고, 이상자엽실생 중 이수체 발생율은 20.4%이었다. 4배체 품종의 방임수분에서 얻어진 이수체 식물은 3개체(4n = 4x-2 = 74), 4개체(4n = 4x-1 = 75), 3개체(4n = 4x+1 = 77)로 총 10개체이었다. 4배체 16품종간 교배실생에서 이상자엽의 발생빈도는 3.4%이었다. 이상자엽실생 중 이수체 발생율은 22.0%이었다. 4배체 품종간 교배에서 얻어진 이수체 식물은 2개체(2n = 4x-2 = 74), 9개체(2n = 4x-1 = 75), 1개체(2n = 4x+1 = 77), 1개(2n = 4x+3 =79)로 총 13개체이었다. 본 실험결과 4배체 포도품종간 인공교배를 통해서 얻어진 이상자엽실생들은 대부분 이수체식물로 육묘단계에서 효율적인 선발이 가능성한 것으로 나타냈다.