[학위논문]식물생장촉진미생물이 수경재배 오이의 생육과 품질에 미치는 영향 Effects of Plant Growth Promoting Rhizobacteria on the Growth and Fruit Quality of Hydroponically Grown Cucumber plants원문보기
본 연구는 유효토착미생물을 오이의 수경재배에 적용하기 위해 전남지역 오이시설재배지로부터 토양샘플을 채취하여 이 안에 존재하는 미생물 균총으로부터 약 120여종의 단일 미생물을 분리하여 식물생장촉진과 관련한 미생물을 12종으로 재 분리하였다. 이들 미생물은 10종의 Pseudomonas sps. 및 Saccharomyces sp.와 Bacillus sp. 각각 1종이었으며, Pseudomonas sps.는 같은 종끼리, Saccharomyces sp. 와 Bacillus sp.는 두 종을 동시에 수경재배 오이의 생육효과를 실험하여 Pseudomonas sp.와 Saccharomyces sp. 각각 1종을 최종 선발하였다. 생장촉진효과가 확인된 유용세균에 대하여 선별된 미생물의 균주 동정은 BIO LOG SYSTEM과 16S rRNA, 18S rRNA Sequence로 동정하였다. 또한 ...
본 연구는 유효토착미생물을 오이의 수경재배에 적용하기 위해 전남지역 오이시설재배지로부터 토양샘플을 채취하여 이 안에 존재하는 미생물 균총으로부터 약 120여종의 단일 미생물을 분리하여 식물생장촉진과 관련한 미생물을 12종으로 재 분리하였다. 이들 미생물은 10종의 Pseudomonas sps. 및 Saccharomyces sp.와 Bacillus sp. 각각 1종이었으며, Pseudomonas sps.는 같은 종끼리, Saccharomyces sp. 와 Bacillus sp.는 두 종을 동시에 수경재배 오이의 생육효과를 실험하여 Pseudomonas sp.와 Saccharomyces sp. 각각 1종을 최종 선발하였다. 생장촉진효과가 확인된 유용세균에 대하여 선별된 미생물의 균주 동정은 BIO LOG SYSTEM과 16S rRNA, 18S rRNA Sequence로 동정하였다. 또한 주사전자현미경을 통하여 형태적 특성을 검토하여 각각 동정하였다. 최종적으로 선발된 두 종의 미생물이 오이의 수경재배시 근권미생물로서 역할을 할 수 있는 가능성을 알아보고자 식물호르몬 생산가능성, H^(+)-ATPase 활성 및 양액내 phenol 함량 등을 조사하였다. 이들 두 종류의 균주들에 대하여 동정한 결과 M1-M10까지의 균주는 Pseudomonas sp.이었는데 이들 중 특히 효과가 증명된 M2 균주는 Pseudomonas pavonacei와 99%이상의 유사성을 가졌으며 본 실험에서는 Pseudomonas sp. CPS라 명명하였다. 이는 일반적으로 PGPR로 알려진 균주 중의 대표적인 것으로 이미 보고된 바가 있다. Saccharomyces sp.는 18S rRNA 분석 결과 Saccharomyces cariocanus와 94%의 유사도를 보였으며 Saccharomyces sp. D2로 명명 사용하였다. 최종 선발된 Pseudomonas sp. CPS와 Saccharomyces sp. D2에 의한 뿌리강화와 생육 촉진 기작으로 이 미생물들이 작물 뿌리와 상호작용을 통하여 auxin을 분비하며, bacterial auxin이 뿌리의 H^(+)-ATPase 유전자 발현을 조절하여 뿌리의 흡수기능은 향상시키고 결과적으로 작물의 생육이 촉진됨을 확인하였다. 또한 미생물들이 작물 수경재배시 양액내에 축적되는 phenolic compound 들의 toxic효과를 완화시킴으로써 뿌리 기능을 향상시킨다는 것도 확인하였다. 이러한 토양유래 미생물을 오이의 수경재배에 응용하고자 우선, 수경재배 오이의 근권내 지속적인 번식을 위하여 housing 시스템을 모색한 결과 sodium alginate를 이용한 미생물의 비드화를 구상하였으며, 비드화 미생물과 액상 미생물의 생육효과 차이, 비드화 미생물의 적정량을 조사하였다. 또한 housing 시스템에 적합한 전용배지 및 양액을 선발하고자 펄라이트, 코코피트 및 믹스라이트(펄라이트+코코피트, 3:7, v/v), 화란PBG, 일본JBS 및 벨기에EVRDC 오이 전용양액, 그리고 화란PBG 양액의 농도(1/4, 1/2, 1 및 2배액)별 실험을 각각 실시하였다. 이들 실험결과를 종합하여 최종적으로 식물생장촉진형 미생물 비드화가 수경재배 오이의 과실 수량 및 품질에 미치는 효과를 실험하였다. 이 미생물들을 수경재배에 활용하기 위한 배지로는 mixlite (cocopeat : perlite, 7:3), 양액으로는 PBG가 적합하였다. 미생물은 0.5%-1%농도로 배지에 혼합하였을 때 최대의 촉진 효과가 나타났다. 작물의 재배기간동안 미생물들의 농도 유지와 작물 뿌리와의 접촉을 유지하기 위하여 alginate로 비드화함으로써 미생물의 생육 촉진 효과를 더욱 높일 수 있었으며 오이의 생육 촉진 효과가 Pseudomonas sp. CPS는 처리 후 2-3주에서 D2는 4-5주에서 최대치를 보였는데 이 결과로서 4-5주 간격으로 미생물을 재처리하는 것이 효과적임을 밝혔다. 이들 미생물들이 과실수량과 품질에 미치는 효과는 생장에 효과적인 Saccharomyces sp. D2처리구에서 과장, 당도, 평균 착과수 및 평균 과중이 대조구보다 더 높게 나타났다. Pseudomonas sp. CPS처리구는 대조구와 통계적 유의차는 보이지 않았으나 다소 높게 나타났다. 이들 두 근권미생물이 오이의 생육과 과실수량 및 품질반응에 좋은 영향을 미친 것은 오이의 생리활성기능 변화에 미치는 영향 이외에도 하루동안의 광합성량을 측정한 결과로 설명할 수 있었으며, 광합성의 패턴은 Saccharomyces sp. D2처리구에서 가장 효율적으로 유지되었으며, Pseudomonas sp. CPS처리구가 그 다음이었다. 이는 Saccharomyces sp. D2구에서 엽면적이 가장 넓게 유지되었기 때문인 것으로 생각되었으며, 이러한 높은 광합성 효율이 뿌리에서 유기물을 많이 분비하게 하고, 따라서 과실의 생산량과 품질에 좋은 영향을 끼친 것으로 판단되었다.
본 연구는 유효토착미생물을 오이의 수경재배에 적용하기 위해 전남지역 오이시설재배지로부터 토양샘플을 채취하여 이 안에 존재하는 미생물 균총으로부터 약 120여종의 단일 미생물을 분리하여 식물생장촉진과 관련한 미생물을 12종으로 재 분리하였다. 이들 미생물은 10종의 Pseudomonas sps. 및 Saccharomyces sp.와 Bacillus sp. 각각 1종이었으며, Pseudomonas sps.는 같은 종끼리, Saccharomyces sp. 와 Bacillus sp.는 두 종을 동시에 수경재배 오이의 생육효과를 실험하여 Pseudomonas sp.와 Saccharomyces sp. 각각 1종을 최종 선발하였다. 생장촉진효과가 확인된 유용세균에 대하여 선별된 미생물의 균주 동정은 BIO LOG SYSTEM과 16S rRNA, 18S rRNA Sequence로 동정하였다. 또한 주사전자현미경을 통하여 형태적 특성을 검토하여 각각 동정하였다. 최종적으로 선발된 두 종의 미생물이 오이의 수경재배시 근권미생물로서 역할을 할 수 있는 가능성을 알아보고자 식물호르몬 생산가능성, H^(+)-ATPase 활성 및 양액내 phenol 함량 등을 조사하였다. 이들 두 종류의 균주들에 대하여 동정한 결과 M1-M10까지의 균주는 Pseudomonas sp.이었는데 이들 중 특히 효과가 증명된 M2 균주는 Pseudomonas pavonacei와 99%이상의 유사성을 가졌으며 본 실험에서는 Pseudomonas sp. CPS라 명명하였다. 이는 일반적으로 PGPR로 알려진 균주 중의 대표적인 것으로 이미 보고된 바가 있다. Saccharomyces sp.는 18S rRNA 분석 결과 Saccharomyces cariocanus와 94%의 유사도를 보였으며 Saccharomyces sp. D2로 명명 사용하였다. 최종 선발된 Pseudomonas sp. CPS와 Saccharomyces sp. D2에 의한 뿌리강화와 생육 촉진 기작으로 이 미생물들이 작물 뿌리와 상호작용을 통하여 auxin을 분비하며, bacterial auxin이 뿌리의 H^(+)-ATPase 유전자 발현을 조절하여 뿌리의 흡수기능은 향상시키고 결과적으로 작물의 생육이 촉진됨을 확인하였다. 또한 미생물들이 작물 수경재배시 양액내에 축적되는 phenolic compound 들의 toxic효과를 완화시킴으로써 뿌리 기능을 향상시킨다는 것도 확인하였다. 이러한 토양유래 미생물을 오이의 수경재배에 응용하고자 우선, 수경재배 오이의 근권내 지속적인 번식을 위하여 housing 시스템을 모색한 결과 sodium alginate를 이용한 미생물의 비드화를 구상하였으며, 비드화 미생물과 액상 미생물의 생육효과 차이, 비드화 미생물의 적정량을 조사하였다. 또한 housing 시스템에 적합한 전용배지 및 양액을 선발하고자 펄라이트, 코코피트 및 믹스라이트(펄라이트+코코피트, 3:7, v/v), 화란PBG, 일본JBS 및 벨기에EVRDC 오이 전용양액, 그리고 화란PBG 양액의 농도(1/4, 1/2, 1 및 2배액)별 실험을 각각 실시하였다. 이들 실험결과를 종합하여 최종적으로 식물생장촉진형 미생물 비드화가 수경재배 오이의 과실 수량 및 품질에 미치는 효과를 실험하였다. 이 미생물들을 수경재배에 활용하기 위한 배지로는 mixlite (cocopeat : perlite, 7:3), 양액으로는 PBG가 적합하였다. 미생물은 0.5%-1%농도로 배지에 혼합하였을 때 최대의 촉진 효과가 나타났다. 작물의 재배기간동안 미생물들의 농도 유지와 작물 뿌리와의 접촉을 유지하기 위하여 alginate로 비드화함으로써 미생물의 생육 촉진 효과를 더욱 높일 수 있었으며 오이의 생육 촉진 효과가 Pseudomonas sp. CPS는 처리 후 2-3주에서 D2는 4-5주에서 최대치를 보였는데 이 결과로서 4-5주 간격으로 미생물을 재처리하는 것이 효과적임을 밝혔다. 이들 미생물들이 과실수량과 품질에 미치는 효과는 생장에 효과적인 Saccharomyces sp. D2처리구에서 과장, 당도, 평균 착과수 및 평균 과중이 대조구보다 더 높게 나타났다. Pseudomonas sp. CPS처리구는 대조구와 통계적 유의차는 보이지 않았으나 다소 높게 나타났다. 이들 두 근권미생물이 오이의 생육과 과실수량 및 품질반응에 좋은 영향을 미친 것은 오이의 생리활성기능 변화에 미치는 영향 이외에도 하루동안의 광합성량을 측정한 결과로 설명할 수 있었으며, 광합성의 패턴은 Saccharomyces sp. D2처리구에서 가장 효율적으로 유지되었으며, Pseudomonas sp. CPS처리구가 그 다음이었다. 이는 Saccharomyces sp. D2구에서 엽면적이 가장 넓게 유지되었기 때문인 것으로 생각되었으며, 이러한 높은 광합성 효율이 뿌리에서 유기물을 많이 분비하게 하고, 따라서 과실의 생산량과 품질에 좋은 영향을 끼친 것으로 판단되었다.
This study was conducted to identify the plant growth promoting rhizobacteria (PGPRs) from soil sample which is mixture of indigenous microorganisms and to improve yield and quality of hydroponically grown cucumber plants through enhancing the availability of selected microorganisms. 120 strains wer...
This study was conducted to identify the plant growth promoting rhizobacteria (PGPRs) from soil sample which is mixture of indigenous microorganisms and to improve yield and quality of hydroponically grown cucumber plants through enhancing the availability of selected microorganisms. 120 strains were selected from this soil sample and 12 strains of them were re-selected relating to the promotion of plant growth. These selected microorganisms were composed of 10 kinds of Pseudomonas sp., one Saccharomyces sp. and one Bacillus sp. to investigate their capability of plant growth promoting effects, respectively. Through these processes, one Pseudomonas sp. and one Saccahromyces sp. were selected. For identification of these effective microorganisms, 16s rRNA and 18s rRNA gene sequence analysis were performed on Pseudomonas sp. and Saccharomyces sp., respectively. And characteristic feature was also investigated using by scanning electron microscope (SEM). To know the availability of these two selected microorganisms in hydroponics of cucumber plants, the capability of producing plant hormone by microorganisms, the effects of them on the activity of H^(+)-ATPase and the reduction of phenol content in nutrient solution were investigated. 10 strains from M1 to M10 were identified to Pseudomonas sp. Especially, M2, which was determined as the best microorganism of 10 Pseudomonas sp., had almost same genes with Pseudomonas pavonacei (about 99%), and it was named as Pseudomonas sp. CPS. Another strain, Saccharomyces sp. was similar to Saccharomycs cariocanus (about 94%), and it was named as Saccharomyces sp. D2. This study identified that Pseudomonas sp. CPS and Saccharomyces sp. D2 secreted IAA by the exogenous tryptophan supply and also by the interaction with the plant roots. Pseudomonas sp. CPS and Saccharomyces sp. D2 were multiplied and formed colony around the plant roots through the interactions with roots. Microorganism treated root exudates were analysed by salkowski's reagent and HPLC, and IAA amount in the exudates of Pseudomonas sp. CPS and Saccharomyces sp. D2 treated roots increased are culture time extended until 120hrs, but Saccharomyces sp. D2 secreted 7 times higher amount of IAA than a Pseudomonas sp. CPS at 120hrs culture time. The sub-tropical plants like a cucumber cease the growth due to a decline of root activities under the circumstance of low soil temperature and defective transport of nutrients. H^(+)-ATPase of root plasma membrane is well known to be related to the absorptive function of the ions and nutrients. We investigated the changes of H^(+)-ATPase activities with the microorganism treatments as the criteria of root growth and development. The enzyme activity of Pseudomonas sp. CPS treated roots showed the highest activity after 2-3weeks and Saccharomyces sp. D2 treated roots after 4-5weeks, and around 30% increment of the enzyme activities compared to the control roots. Root death of hydroponically grown cucumber occurred in long-term cultivation and continuous cropping. This phenomenon could reduce growth of cucumber plant as extend growing period. Therefore, phenolic compound, one of allelopathic substances in the nutrient solution sampled from cucumber growing bed were analyzed in the course of growth period. The longer the growing period and times of reusing nutrient solution, the higher the content of phenolic compound in the nutrient solution. Phenol compounds in nutrient solution affected severely in shoot and root growth reduction. Linear reduction was observed according to the amount of phenolic compound secreted from roots. One of the main factors of autotoxicity of root zone in solution culture was demonstrated as phenolic compounds. Phenolic compound content was about 10 ppm in new substrate, and it was lower 7 times than that of reused substrate. The content of phenolic compound in reused nutrient solution treated microorganisms was higher than that of new nutrient solution, but lower than that of reused nutrient solution non-treated microorganisms. It also appeared that Saccharomyces sp. D2 suppressed phenolic compound than that of Pseudomonas sp. CPS. As above results, to optimize environmental condition for maintaining selected microorganisms Pseudomonas sp. CPS and Saccharomyces sp. D2 in hydroponic system, housing system was designed for concentrating selected microorganisms into rhizosphere of hydroponic system. To do this, alginate which have a high molecule possessing the structure of polyuronide and extracted from seaweed was used for bead making as housing system. Growth characteristics in terms of plant height, leaf area, shoot and root fresh and dry weight were better in all plots of Pseudomonas. sp. CPS and Saccharomyces sp. D2 than those of control. Especially, in the plot of Saccharomyces sp. D2 bead treated, it showed more over 130% growth promotion than that of control. In comparison of the growth between liquid and bead type of Pseudomonas sp. CPS and Saccharomyces sp. D2, both Pseudomonas. sp. CPS and Saccharomyces sp. D2 bead showed more growth enhancement than that of liquid. Alginate bead treatment with selected microorganism Pseudomonas. sp. CPS and Saccharomyces sp. D2 has appeared to be more effective growth promotion than that of liquid treatment. Hence, to determine the optimal concentration of alginate bead treatment with Pseudomonas sp. CPS and Saccharomyces sp. D2. Pseudomonas sp. CPS bead was treated with 0.5, 1.0, 3.0 and 10.0g / plant and Saccharomyces sp. D2 bead treated with 0.25, 0.5, 1.0 and 5.0g / plant to contact directly with roots in substrate. In all plots except 10.0g Pseudomonas sp. CPS, the growth was better than that of control. The optimal concentration for the growth promotion of cucumber plants was found in the range from 0.5 to 1.0g and 0.25 to 0.5g on Pseudomonas sp. CPS and Saccharomyces sp. D2 bead, respectively. According to the optimal concentrations were determined as 0.5g Pseudomonas sp. CPS and 0.25g Saccharomyces sp. D2 for improving the growth of cucumber plant, optimum substrate and nutrient solution for maintaining microorganisms were investigated. First, to select the most suitable substrate for alginate bead treatment of microorganism Pseudomonas. sp. CPS and Saccharomyces sp. D2, Pseudomonas sp. CPS and Saccharomyces sp. D2 bead were treated with 0.5 and 0.25g / plant, respectively, to contact directly with roots into substrate. The kinds of substrates were perlite, cocopeat and perlite plus cocopeat (hereinafter mixlite, 3:7, v/v), respectively. Generally, almost all growth characteristics were better in mixlite than those of perlite or cocopeat. Also, in all kinds of substrates, Saccharomyces sp. D2 bead increased the growth characteristics in terms of plant, the number of leaves, leaf area, shoot fresh and dry weight and root fresh and dry weight. Second, to select the optimal nutrient solution formula for alginate bead treatment of microorganism Pseudomonas. sp. CPS and Saccharomyces sp. D2, Pseudomonas sp. CPS and Saccharomyces sp. D2 bead were treated with 0.5 and 0.25g / plant, respectively, to contact directly with roots into substrate. The kinds of nutrient solution were PBG solution recommended by Research Station for Floriculture & Vegetables in Holland, JBS solution recommended by Japanese Horticultural Experiment Station and EVRDC solution recommended by Europe Vegetables Research & Development Center in Belgium, respectively. Substrate used was mixlite. The growth of cucumber plants were good in control with JBS solution and in the plots of Pseudomonas. sp. CPS and Saccharomyces sp. D2 with PBG solution, respectively. In control, however, root growth was better in PBG solution than that of JBS solution. In the plots of Pseudomonas. sp. CPS and Saccharomyces sp. D2, root growth showed best result in PBG solution. Third, to determine the optimal concentration of PBG solution for alginate bead treatment of microorganism Pseudomonas. sp. CPS and Saccharomyces sp. D2, Pseudomonas sp. CPS and Saccharomyces sp. D2 bead were treated with 0.5 and 0.25g / plant, respectively, to contact directly with roots into substrate. The strengths of PBG solution were ¼, ½, 1(2.0dS/m, pH 5.8-6.2) and 2 ionic strength. The optimal concentration of PBG solution for growth characteristics in terms of plant height, leaf area and shoot growth appeared to be standard solution, 1 time. In the plots of 1/4 and 2 times, early growth was inhibited markedly. Especially, in the plot of 1/4 times, chlorophyll content was lower than those of the other treatment, However, as increasing the concentration or treating Pseudomonas. sp. CPS and Saccharomyces sp. D2 bead with 1/4 times, it occurred to be greener gradually. In case of Saccharomyces sp. D2 bead, the plot of 1/2 times showed the growth promotion equivalent to that of 1 times, it was considered that Saccharomyces sp. D2 increased nutrient and water uptake of cucumber plants. Finally, to investigate the effect of alginate bead incorporated of Pseudomonas. sp. CPS and Saccharomyces sp. D2 selected under various environmental condition on the growth and fruit quality of hydroponically grown cucumber plants, field application was tested. cucumber cv. Chungnakhap was transplanted to styrofoam bed filled with mixlite at 30 days after sowing. Planting density was 30cm between plants and PBG solution (EC 2.0dS/m, pH 5.8-6.2) was fed. Pseudomonas sp. CPS and Saccharomyces sp. D2 bead were treated with 0.5 and 0.25g / plant, respectively, to contact directly with roots into substrate. To maintain microbial density, 0.5% Pseudomonas sp. CPS and Saccharomyces sp. D2 liquid were drenched into rhizosphere at 45 and 60 DAT, respectively. In the treated plot of Saccharomyces sp. D2 bead, plant height was 279.7cm and more over 30cm than those of Pseudomonas sp. CPS bead and control, and stem diameter was thicker too. The number of leaves was much more over 2 leaves than that of control. Also, leaf area was much larger in proportion to the number of leaves. In the plot of Saccharomyces sp. D2 bead treatment showing the growth promotion, fruit quality in terms of fruit length, sugar degree, average fruit number and fruit weight were higher than those of control and Pseudomonas sp. CPS bead. In the treated plot of Pseudomonas sp. CPS bead, sugar degree and average fruit number were higher than those of control, but fruit length and average fruit weight were slightly lower than that of control. Total fruit number and weight were not showed among treatments in early harvesting stage, after that, the treated plot of Saccharomyces sp. D2 bead had more yield than those of Pseudomonas sp. CPS bead and control. In the treated plot of Pseudomonas sp. CPS bead, growth rate was similar with control, but total fruit number and weight were much more than that of control due to producing more fruit number per plant. Photosynthetic rate of 15th full opened leaf was higher in the treated plot of Saccharomyces sp. D2 bead than those of Pseudomonas sp. CPS bead and control at 30 DAT. These results were considered increasing fruit yield and quality.
This study was conducted to identify the plant growth promoting rhizobacteria (PGPRs) from soil sample which is mixture of indigenous microorganisms and to improve yield and quality of hydroponically grown cucumber plants through enhancing the availability of selected microorganisms. 120 strains were selected from this soil sample and 12 strains of them were re-selected relating to the promotion of plant growth. These selected microorganisms were composed of 10 kinds of Pseudomonas sp., one Saccharomyces sp. and one Bacillus sp. to investigate their capability of plant growth promoting effects, respectively. Through these processes, one Pseudomonas sp. and one Saccahromyces sp. were selected. For identification of these effective microorganisms, 16s rRNA and 18s rRNA gene sequence analysis were performed on Pseudomonas sp. and Saccharomyces sp., respectively. And characteristic feature was also investigated using by scanning electron microscope (SEM). To know the availability of these two selected microorganisms in hydroponics of cucumber plants, the capability of producing plant hormone by microorganisms, the effects of them on the activity of H^(+)-ATPase and the reduction of phenol content in nutrient solution were investigated. 10 strains from M1 to M10 were identified to Pseudomonas sp. Especially, M2, which was determined as the best microorganism of 10 Pseudomonas sp., had almost same genes with Pseudomonas pavonacei (about 99%), and it was named as Pseudomonas sp. CPS. Another strain, Saccharomyces sp. was similar to Saccharomycs cariocanus (about 94%), and it was named as Saccharomyces sp. D2. This study identified that Pseudomonas sp. CPS and Saccharomyces sp. D2 secreted IAA by the exogenous tryptophan supply and also by the interaction with the plant roots. Pseudomonas sp. CPS and Saccharomyces sp. D2 were multiplied and formed colony around the plant roots through the interactions with roots. Microorganism treated root exudates were analysed by salkowski's reagent and HPLC, and IAA amount in the exudates of Pseudomonas sp. CPS and Saccharomyces sp. D2 treated roots increased are culture time extended until 120hrs, but Saccharomyces sp. D2 secreted 7 times higher amount of IAA than a Pseudomonas sp. CPS at 120hrs culture time. The sub-tropical plants like a cucumber cease the growth due to a decline of root activities under the circumstance of low soil temperature and defective transport of nutrients. H^(+)-ATPase of root plasma membrane is well known to be related to the absorptive function of the ions and nutrients. We investigated the changes of H^(+)-ATPase activities with the microorganism treatments as the criteria of root growth and development. The enzyme activity of Pseudomonas sp. CPS treated roots showed the highest activity after 2-3weeks and Saccharomyces sp. D2 treated roots after 4-5weeks, and around 30% increment of the enzyme activities compared to the control roots. Root death of hydroponically grown cucumber occurred in long-term cultivation and continuous cropping. This phenomenon could reduce growth of cucumber plant as extend growing period. Therefore, phenolic compound, one of allelopathic substances in the nutrient solution sampled from cucumber growing bed were analyzed in the course of growth period. The longer the growing period and times of reusing nutrient solution, the higher the content of phenolic compound in the nutrient solution. Phenol compounds in nutrient solution affected severely in shoot and root growth reduction. Linear reduction was observed according to the amount of phenolic compound secreted from roots. One of the main factors of autotoxicity of root zone in solution culture was demonstrated as phenolic compounds. Phenolic compound content was about 10 ppm in new substrate, and it was lower 7 times than that of reused substrate. The content of phenolic compound in reused nutrient solution treated microorganisms was higher than that of new nutrient solution, but lower than that of reused nutrient solution non-treated microorganisms. It also appeared that Saccharomyces sp. D2 suppressed phenolic compound than that of Pseudomonas sp. CPS. As above results, to optimize environmental condition for maintaining selected microorganisms Pseudomonas sp. CPS and Saccharomyces sp. D2 in hydroponic system, housing system was designed for concentrating selected microorganisms into rhizosphere of hydroponic system. To do this, alginate which have a high molecule possessing the structure of polyuronide and extracted from seaweed was used for bead making as housing system. Growth characteristics in terms of plant height, leaf area, shoot and root fresh and dry weight were better in all plots of Pseudomonas. sp. CPS and Saccharomyces sp. D2 than those of control. Especially, in the plot of Saccharomyces sp. D2 bead treated, it showed more over 130% growth promotion than that of control. In comparison of the growth between liquid and bead type of Pseudomonas sp. CPS and Saccharomyces sp. D2, both Pseudomonas. sp. CPS and Saccharomyces sp. D2 bead showed more growth enhancement than that of liquid. Alginate bead treatment with selected microorganism Pseudomonas. sp. CPS and Saccharomyces sp. D2 has appeared to be more effective growth promotion than that of liquid treatment. Hence, to determine the optimal concentration of alginate bead treatment with Pseudomonas sp. CPS and Saccharomyces sp. D2. Pseudomonas sp. CPS bead was treated with 0.5, 1.0, 3.0 and 10.0g / plant and Saccharomyces sp. D2 bead treated with 0.25, 0.5, 1.0 and 5.0g / plant to contact directly with roots in substrate. In all plots except 10.0g Pseudomonas sp. CPS, the growth was better than that of control. The optimal concentration for the growth promotion of cucumber plants was found in the range from 0.5 to 1.0g and 0.25 to 0.5g on Pseudomonas sp. CPS and Saccharomyces sp. D2 bead, respectively. According to the optimal concentrations were determined as 0.5g Pseudomonas sp. CPS and 0.25g Saccharomyces sp. D2 for improving the growth of cucumber plant, optimum substrate and nutrient solution for maintaining microorganisms were investigated. First, to select the most suitable substrate for alginate bead treatment of microorganism Pseudomonas. sp. CPS and Saccharomyces sp. D2, Pseudomonas sp. CPS and Saccharomyces sp. D2 bead were treated with 0.5 and 0.25g / plant, respectively, to contact directly with roots into substrate. The kinds of substrates were perlite, cocopeat and perlite plus cocopeat (hereinafter mixlite, 3:7, v/v), respectively. Generally, almost all growth characteristics were better in mixlite than those of perlite or cocopeat. Also, in all kinds of substrates, Saccharomyces sp. D2 bead increased the growth characteristics in terms of plant, the number of leaves, leaf area, shoot fresh and dry weight and root fresh and dry weight. Second, to select the optimal nutrient solution formula for alginate bead treatment of microorganism Pseudomonas. sp. CPS and Saccharomyces sp. D2, Pseudomonas sp. CPS and Saccharomyces sp. D2 bead were treated with 0.5 and 0.25g / plant, respectively, to contact directly with roots into substrate. The kinds of nutrient solution were PBG solution recommended by Research Station for Floriculture & Vegetables in Holland, JBS solution recommended by Japanese Horticultural Experiment Station and EVRDC solution recommended by Europe Vegetables Research & Development Center in Belgium, respectively. Substrate used was mixlite. The growth of cucumber plants were good in control with JBS solution and in the plots of Pseudomonas. sp. CPS and Saccharomyces sp. D2 with PBG solution, respectively. In control, however, root growth was better in PBG solution than that of JBS solution. In the plots of Pseudomonas. sp. CPS and Saccharomyces sp. D2, root growth showed best result in PBG solution. Third, to determine the optimal concentration of PBG solution for alginate bead treatment of microorganism Pseudomonas. sp. CPS and Saccharomyces sp. D2, Pseudomonas sp. CPS and Saccharomyces sp. D2 bead were treated with 0.5 and 0.25g / plant, respectively, to contact directly with roots into substrate. The strengths of PBG solution were ¼, ½, 1(2.0dS/m, pH 5.8-6.2) and 2 ionic strength. The optimal concentration of PBG solution for growth characteristics in terms of plant height, leaf area and shoot growth appeared to be standard solution, 1 time. In the plots of 1/4 and 2 times, early growth was inhibited markedly. Especially, in the plot of 1/4 times, chlorophyll content was lower than those of the other treatment, However, as increasing the concentration or treating Pseudomonas. sp. CPS and Saccharomyces sp. D2 bead with 1/4 times, it occurred to be greener gradually. In case of Saccharomyces sp. D2 bead, the plot of 1/2 times showed the growth promotion equivalent to that of 1 times, it was considered that Saccharomyces sp. D2 increased nutrient and water uptake of cucumber plants. Finally, to investigate the effect of alginate bead incorporated of Pseudomonas. sp. CPS and Saccharomyces sp. D2 selected under various environmental condition on the growth and fruit quality of hydroponically grown cucumber plants, field application was tested. cucumber cv. Chungnakhap was transplanted to styrofoam bed filled with mixlite at 30 days after sowing. Planting density was 30cm between plants and PBG solution (EC 2.0dS/m, pH 5.8-6.2) was fed. Pseudomonas sp. CPS and Saccharomyces sp. D2 bead were treated with 0.5 and 0.25g / plant, respectively, to contact directly with roots into substrate. To maintain microbial density, 0.5% Pseudomonas sp. CPS and Saccharomyces sp. D2 liquid were drenched into rhizosphere at 45 and 60 DAT, respectively. In the treated plot of Saccharomyces sp. D2 bead, plant height was 279.7cm and more over 30cm than those of Pseudomonas sp. CPS bead and control, and stem diameter was thicker too. The number of leaves was much more over 2 leaves than that of control. Also, leaf area was much larger in proportion to the number of leaves. In the plot of Saccharomyces sp. D2 bead treatment showing the growth promotion, fruit quality in terms of fruit length, sugar degree, average fruit number and fruit weight were higher than those of control and Pseudomonas sp. CPS bead. In the treated plot of Pseudomonas sp. CPS bead, sugar degree and average fruit number were higher than those of control, but fruit length and average fruit weight were slightly lower than that of control. Total fruit number and weight were not showed among treatments in early harvesting stage, after that, the treated plot of Saccharomyces sp. D2 bead had more yield than those of Pseudomonas sp. CPS bead and control. In the treated plot of Pseudomonas sp. CPS bead, growth rate was similar with control, but total fruit number and weight were much more than that of control due to producing more fruit number per plant. Photosynthetic rate of 15th full opened leaf was higher in the treated plot of Saccharomyces sp. D2 bead than those of Pseudomonas sp. CPS bead and control at 30 DAT. These results were considered increasing fruit yield and quality.
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