• Journal of Bio-Environment Control
• /
• v.8 no.1
• /
• pp.36-41
• /
• 1999

This study was carried out to investigate the effect of root zone restriction on yield and quality of muskmelon. Three cultivation methods, isolated bench, root zone restriction sheet(RZR sheet) and conventional soil culture, were compared from April 19th to July 17th. Soil temperature was higher at isolated bench and the growth of melon was accelerated at isolated bench compared to soil culture or RZR sheet. Fruit size was bigger in order of soil culture, isolated bench and RZR sheet, while sugar content and net shape were greatest at isolated bench, and the percentage of wilted plant was 3.3% at isolated bench, 25.0% at RZR sheet and 26.7% at soil culture. Therefore, marketable yield was higher at isolated bench compared to conventional soil culture.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 1998.10a
• /
• pp.142-145
• /
• 1998

근권용량을 2, 4, 6, 8 및 10$\ell$로 제한하여 펄라이트를 채워 오이를 재배한 결과 근권용적이 증가할수록 초장, 경경, 엽수 및 엽면적이 증가하였고, 과실수와 과실중량에서는 근권용적이 큰 8$\ell$와 10$\ell$의 처리구에서 가장 양호하였으며 기형과 발생률도 낮은 경향이었다. 근권용적 6$\ell$를 기준으로 미만의 처리구에 비해 이상의 처리구에서 경으로의 건물분배가 줄어들고 엽으로의 건물분배가 많은 것을 볼 수 있었다.

• Horticultural Science & Technology
• /
• v.28 no.3
• /
• pp.415-422
• /
• 2010

Two leaf lettuces, chicory, endive, edible chrysanthemum, and pak-choi were hydroponically cultured under root restricted conditions in a deep flow technique system and their growth and nutritional values were investigated. Cylindrical plastic tubes with 100 mm height and diameters of 20, 25 or 30 mm were used for root restriction. Growth of all species was retarded by 25-95% as the roots zone was restricted. Pak-choi and edible chrysanthemum showed greater reduction in growth as compared with chicory and endive. Percent dry matter, C/N ratio, and contents of total ascorbic acid and total anthocyanin increased in the root restricted treatments. Contents of P and K decreased in the root restricted treatments, while contents of Mg, Fe, Mn, and Zn were not consistent among the tested species. Optimized root volumes to improve the nutritional values and to reduce the growth retardation varied depending on species of leafy vegetables. Tubes of ${\Phi}25mm{\times}100mm$ and ${\Phi}30mm{\times}100mm$ were suitable for chicory, endive and lettuce, and edible chrysanthemum and pak-choi, respectively. Results indicate that nutritional values of hydroponically-cultured leafy vegetables can be improved by root restriction.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 1998.10a
• /
• pp.134-137
• /
• 1998

최근 고급 과채류에 대한 선호도가 높아짐에 따라 네트멜론의 재배가 증가되고 있는 추세이다. 그러나 주산단지에서는 고정된 시설에서 주년 재배하므로서 연작으로 인한 토양병해충 발생이 증가되고 염류집적 등의 문제가 심화되고 있다(박, 1995). 멜론 재배기술이 비교적 앞서 있는 일본에서는 이러한 연작장해를 회피하기 위한 방법으로 격리상이나 차근시트 등을 이용한 근권제한재배에 관한 연구가 다년간 이루어져 왔다. (중략)

• Journal of Bio-Environment Control
• /
• v.6 no.4
• /
• pp.235-241
• /
• 1997

This study was performed to investigate the behaviour of root zone environments under the control of soil temperature and tension of soil moisture near the root Bone of 'Kyoho' grapes tree grown on restricted root zone system in plastic greenhouse. Maximum diurnal air temperature inside plastic greenhouse ranged between 25.1 and 32.7$^{\circ}C$, and the average of nocturnal air temperature inside plastic greenhouse maintained at 18$^{\circ}C$ in winter season. Also the minimum diurnal relative humidity ranged between 50 and 55%, and the maximum nocturnal relative humidity ranged between 84 to 87%. At a depth of 15cm from soil surface, the average soil temperature maintained at 25.6$^{\circ}C$ for under-ground heating, and appeared to 17.4$^{\circ}C$ for unheated condition. Although the tension of soil moisture just after irrigation sharply decreased to pF 1.5, the tension of soil moisture at the depth of 15cm maintained at pF 2.0~2.2. It is suggested that the tension of soil moisture at the depth of 15cm might be used as the standard for the determination of irrigation set point. Effective drainage system is needed to prevent the spindly and succulent growth of vine trees grown in restricted root zone system.

• Horticultural Science & Technology
• /
• v.19 no.3
• /
• pp.367-372
• /
• 2001

'Kyoho' grape (Vitis labruscana L.) has currently cropped twice a year in plastic greenhouses. However, there are problems with low fruit quality in the second cropping owing to low temperatures and short photoperiods. This experiment was conducted to investigate the effect of root zone heating and $CO_2$ enrichment in plastic greenhouse on the vine growth and fruit quality of 'Kyoho' grape in double cropping system. The internode length of shoots, leaf area and leaf dry weight at the treatment of soil heating near root zone was significantly different regardless of $CO_2$ enrichment. There were no significant differences in fruit bunch and berry weight, titratable acidity, coloration degree and berry shattering among the treatments, but the soluble solids significantly increased by root zone heating. Photosynthetic rate increased with increasing $CO_2$ concentration from 300 to $800{\mu}mol{\cdot}mol^{-1}$ in sunny day, whereas it didn't increase in cloudy day regardless of $CO_2$ enrichment.

• Research in Plant Disease
• /
• v.16 no.1
• /
• pp.35-40
• /
• 2010

Suppression effect of the 12 bacterial isolates from plant rhizosphere against late blight caused by Phytophthora citrophthora were investigated on citrus fruits. Among the bacterial isolates, THJ609-3, TRH423-3, BRH433-2, Lyso-chit and KRY505-3 presented disease suppression after wound inoculation with the fungal pathogen in vivo. The anti-fungal activity was evaluated by measuring the length of inhibition zone of the mycelium P. citrophthora adjacent to the effective bacterial isolates in which all of the 5 bacterial isolates showed antagonistic effects. However, there was no positive correlations between the efficacy of disease suppression and the antagonistic effect. On the other hand, Lyso-chit and KRY505-3 were identified as Bacillus cereus, BRH433-2 as B. circulans and TRH423-3 as Burkholderia gladioli, respectively, by analysis of rDNA sequence on the internal transcript spaces. It is suggested that the effective bacterial isolates may be useful for finding biological control agents against late blight especially on environment-friendly farm where the application of fungicide is limited.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.41 no.4
• /
• pp.475-481
• /
• 1996

This study was carried out to acquire the basic information of root growth under different pot size, imposing different space limitation on rhizosphere. Different size of pots that had same surface area but different depth, 5cm(Iength)$\times$5cm(width)$\times$30, 15, 5cm(depth), were used during the seedling stage of tobacco plant. Space limitation on rhizosphere affected not only the aerial growth, stem height, leaf area and shoot dry weight, but also root growth and root architecture. Aerial growth was highly related to growth of underground part, so space limitation on rhizosphere decreased aerial growth. Limitation on pot volume by reducing pot depth induced new rooting on crown. Root number and relative multiplication rate were higher in small pot that had 5cm depth than large pot, but total root length and mean extension rate showed reverse patterns. Root numbers of 1st order and 2nd order were increased as pot depth was increased, but the root number of 3rd order was increased in small pot. Root system of seedling grown in large pot distributed more horizontally than that in small pot at 20 days after temporary planting (DAT), but the root architecture of seedling was reversed at 25 DAT.

• Research in Plant Disease
• /
• v.18 no.4
• /
• pp.331-337
• /
• 2012

Citrus melanose is one of important disease in citrus cultivation, reducing quality of citrus fruits and resulting in economic loss. Like other diseases in citrus, melanose was mainly protected by chemical fungicide in the field. Recently, alternative method of disease control is highly required due to the side effect of the chemicals. In this study four rhizobacterial strains TRH423-3, MRL408-3, THJ609-3, and TRH415-2 are selected by dual-culture testing its antifungal activity against Diaporthe citri causing citrus melanose. To investigate the protection efficacy of the selected rhizobacterial strains to citrus melanose, the bacteria were pre-treated on citrus leaves following inoculation with melanose pathogen. Pre-treatment with all selected rhizobacterial strains showed disease suppression in which the levels of protection rates were different by the rhizobacterial strains. Additional treatment with the rhizobacterial strains after the pathogen inoculation enhanced protection rates in all cases. The strain MRL408-3 and TRH423-3 were identified as Burkholderia gladioli, TRH415-2 as Pseudomons fluorescens and THJ609-3 as Pseudomonas pudia as a result of analyzing the internal transcript spaces of the rhizobacterial strains rDNA. The selected rhizobacterial strains may be valuable as biological control agents in the environment-friendly citrus farm in which chemical application is limited.

• Microbiology and Biotechnology Letters
• /
• v.35 no.4
• /
• pp.261-271
• /
• 2007

Phytoremediation is an economic and environmentally friendly technique to remediate contaminated-soil. In this study, the effects of plants, rhizobacteria and physicochemical factors on phytoremediation have been reviewed. For successful phytoremediation, the selection of plants is primarily important. To remediate soil contaminated with petroleum hydrocarbon, raygrass (Lolium multiflorum lam), white mustard, vetch (Vicia villosa), tall fescue (Festuca arundinacea), legumes, poplar, and Pine (Pinus densiflora) were mainly applied, and the removal efficiency of petroleum hydrocarbon were ranged 68 to 99%. Corn (Zea mays), raygrass (Lolium multiflorum lam), vetch (Vicia villosa), mustard, clover (Trifolium repens), and tall fescue (Festuca arundinacea) were used for the removal of polycyclic aromatic hydrocarbon, and their removal efficiencies were 50-98%. Rhizobacteria play significant roles for phytoremediation because they can directly participate in the degradation of contaminant as well as promoting plants growth. The following rhizobacteria were preferred for phytoremediation: Azospirillum lipoferum, Enterobactor cloacae, Azospirillum brasilense, Pseudomonas putida, Burkholderia xenovorans, Comamonas testosterone, Pseudomonas gladioli, Azotobacter chroococcum, Bacillus megaterium, and Bacillus subtilis. Pysicochemical factors such as pH, temperature, nutrient, electron acceptor, water content, organic content, type of contaminants are consequential limiting factors for phytoremediation.