• 농업생명과학연구
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• 제50권2호
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• pp.73-82
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• 2016

본 연구에서는 내건성 식물 선발을 위한 최적 인자를 구명하고, 이들 내건성 식물들의 생장특성을 조사하였다. 건조저항인자에 대한 나머지 건조저항일(RD), 엽면적(LD), 단위증산량(UTR), 상대함수량(RWC), 상대수분손실량(RWL), 엽면적(LA), 기공수(SN) 및 기공면적(SA) 등 6개 인자들을 비교한 결과 상대수분손실량과 단위증산량이 건조저항일에 많은 영향을 주는 것으로 나타났다. PCA분석 결과 SA, LA, RD는 한그룹으로 RWC와 SN은 다른 한 그룹으로 구분되었고, UTR은 SA, LA와, RWL은 RWC와 SN과 음의 상관을 보였다. 상기 결과를 종합하여 느릅나무, 도깨비바늘, 뚝갈, 매듭풀, 새, 더위지기, 맑은대쑥, 독말풀, 긴담배풀, 소리쟁이, 비수리, 장구채, 개기장, 도깨비가지를 내건성 식물 종으로 선발하였고, 이들에 대한 생장시험을 수행하였다. 절토사면지에서 내건성 식물의 줄기생장은 식물 종간에 약간의 차이를 보였는데, 줄기생장과 잎의 수는 느릅나무를 제외하고 폿트에서는 차이를 보이지 않았다. 그러나 절토사면지에서 내건성 식물 뿌리 생장과 T/R율은 폿트생장과 큰 차이를 보였고, 특히 T/R율은 폿트묘보다 월등히 낮았다. 이 결과로 보아 선발된 내건성 식물은 절토사면지와 같이 척박한 토양에서도 잘 적응할 것으로 나타나 내건성 식물의 육종 등에 이용될 수 있을 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제32권2호
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• pp.160-169
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• 2022

In the present study we evaluated the efficacy of a bioformulation of Streptomyces cameroonensis for control of black pod disease in cocoa and enhancement of seedling growth. The formulation developed using talc powder and cassava starch as carriers showed high shelf-life of 1.07 × 10⁶ CFU/g after six months storage at 4℃. The formulation was tested for inhibition of spore germination in Phytophthora megakarya and showed 100% inhibition at 10% (w/v) of formulation. To determine the efficacy of the formulation, we performed an in planta assay in the greenhouse on two hybrids of cocoa seedlings, the tolerant SNK413 × (♂) T79/467 and the susceptible UPA 134× (♂) SCA 12. Detached leaf assay showed a significant reduction in the disease severity index of about 67% for the tolerant hybrid and 55% for the susceptible hybrid compared to non-treated plants. A significant enhancement in stem length, leaf surface area and root weight was observed. Analysis of biochemical markers of defense showed a significant increase in total polyphenol, flavonoid, and total protein contents. There was also significant upregulation of PR-proteins such as chitinases, peroxidases and β-1, 3-glucanases following treatment of both tolerant and susceptible hybrids, though with a higher level of synthesis in the tolerant hybrids. A significant increase was also observed in polyphenol oxidase activities in plants treated with the formulation. This work demonstrated the stability and effectiveness of the S. cameroonensis powder formulation in suppressing black pod disease in cocoa and subsequently enhancing the growth of seedlings.

• Journal of Microbiology and Biotechnology
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• 제32권11호
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• pp.1435-1446
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• 2022

Zinc-solubilizing bacteria can convert the insoluble form of zinc into soluble forms available to plants. This study was conducted to isolate and screen zinc-solubilizing actinobacteria from rhizosphere soils and to assess their effect on vegetable soybean growth. In total, 200 actinobacteria strains belonging to 10 genera were isolated from rhizosphere soil samples. Among these isolates, four showed zinc solubilization with solubilizing index values ranging from 3.11 to 3.78 on Bunt and Rovira agar supplemented with 0.1% zinc oxide. For the quantitative assay, in broth culture, strains CME34 and EX51 solubilized maximum available zinc contents of 529.71 and 243.58 ㎍/ml. Furthermore, indole-3-acetic acid (IAA) and ammonia were produced by these two strains, the strain CME34 produced the highest amount of IAA 4.62 ㎍/ml and the strain EX51 produced the highest amount of ammonia 361.04 ㎍/ml. In addition, the phosphate-solubilizing abilities in Pikovskaya's medium of CME34 and EX51 were 64.67 and 115.67 ㎍/ml. Based on morphological and biochemical characterization and 16S rDNA sequencing, the strains CME34 and EX51 were closely related to the genus Streptomyces. In a greenhouse experiment, single-strain inoculation of Streptomyces sp. CME34 or EX51 significantly increased the shoot length, root length, plant dry weight, number of pods per plant and number of seeds per plant of vegetable soybean plants compared to the uninoculated control. These findings facilitated the conclusion that the two Streptomyces strains have potential as zinc solubilizers and can be suggested as bioinoculants to promote the growth and yield of soybean.

• 한국약용작물학회지
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• 제28권1호
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• pp.1-8
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• 2020

Background: This study was conducted to investigate the effects of NaCl concentration on the photosynthetic parameters, chlorophyll fluorescence and growth characteristics of Crepidiastrum sonchifolium. Methods and Results: As treatments, we subjected C. sonchifolium plants to four different concentrations of NaCl (0, 50, 100 and 200 mM). We found that the photosynthetic parameters maximum photosynthesis rate (P_{N max}), net apparent quantum yield (Φ), maximum carboxylation rate (V_cmax), and maximum electron transport rate (J_max) were significantly reduced at an NaCl concentration greater than 100 mM. In contrast, there was an increase in water-use efficiency with increasing NaCl concentration, although in terms of growth performances, leaf dry weight, root dry weight, stem length, and total dry weight all decreased with increasing NaCl concentration. Furthermore, leakage of electrolytes, as a consequence of cell membrane damage, clearly increased in response to an increase in NaCl concentration. Analysis of the polyphasic elevation of chlorophyll a fluorescence transients (OKJIP) revealed marked decrease in flux ratios (Φ_PO, Ψ_O and Φ_EO) and the PI_abs, performance index in response to treatment with 200 mM NaCl, thereby reflectings the relatively reduced state of photosystem II. This increase in fluorescence could be due to a reduction in electron transport beyond Q^-_A. We thus found that the photosynthetic parameters, chlorophyll fluorescence and growth characteristics of C. sonchifolium significantly increased in response to treatment with 200 mM NaCl. Conclusions: Collectively, the findings of this study indicate that C. sonchifolium shows relatively low sensitivity to NaCl stress, although photosynthetic activity was markedly reduced in plants exposed to 200 mM NaCl.

• 한국조경학회지
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• 제42권4호
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• pp.48-59
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• 2014

본 연구는 경상남도 창원시의 가음정천에 분포하는 귀화식물을 연구함으로써 복원된 도시하천을 관리하기 위한 기초 자료를 제공하기 위해 수행하였다. 연구결과를 요약하면 다음과 같다. 귀화식물은 17과 36속 43종 2변종 등 총 45분류군으로 요약되었으며, 생태계교란야생식물은 돼지풀과 가시상추 등 2분류군으로 나타났다. 귀화식물의 속성정보를 요약하면, 원산지의 경우, 유럽과 북아메리카가 가장 많았다. 광범위하게 분포하고 개체수가 많은 5등급이 가장 많았으며, 이입시기의 경우, 개항 이후~1921년까지인 1기의 귀화식물이 가장 많았다. 12구간의 경우 귀화율이 41.9%로 가장 높았으며, 9구간 및 19구간은 20.5%로 가장 낮았다. 도시화지수의 경우, 1구간이 가장 높은 6.2%인 반면, 19구간 및 20구간이 가장 낮은 2.5%로 나타났다. 교란율의 경우, 2구간이 가장 높은 16.7%로 나타났다. 귀화식물의 침입원인에 대한 분석 결과, 첫 번째, 물리적 요인은 둔치 및 수로 정비가 직접적으로 영향을 미쳤다고 생각된다. 두 번째, 화학적 요인은 오수 및 탁수 유입, 토사퇴적에 의한 것으로 생각된다. 세 번째, 생물학적 요인은 생태계교란야생식물의 불규칙적인 발생으로 생각되나, 복원과의 상관성을 낮다고 판단된다. 귀화식물의 관리방안을 제시하면, 첫 번째, 교란종 관리는 어린 개체가 발생하는 즉시 제거하거나, 개화 전 화경을 제거하여 번식을 억제하는 물리적 방법이 필요할 것이다. 두 번째, 전국 확산종 관리는 자생식물을 식재하여 생육공간을 제공하지 않는 것이 중요하다. 세 번째, 농경지는 농경행위에 의한 교란과 간섭에 의해 귀화식물의 발생원으로 작용하기 때문에, 하천 내 농경행위를 금지해야 할 것이다. 향후, 창원시의 모든 복원하천에 분포하는 귀화식물을 연구한다면 생태계 변화 특성에 미치는 영향을 예측하는데 유리할 것이다.

• Journal of Microbiology and Biotechnology
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• 제22권4호
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• pp.437-447
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• 2012

Natural and beneficial associations between plants and bacteria have demonstrated potential commercial application for several agricultural crops. The sunflower has acquired increasing importance in Brazilian agribusiness owing to its agronomic characteristics such as the tolerance to edaphoclimatic variations, resistance to pests and diseases, and adaptation to the implements commonly used for maize and soybean, as well as the versatility of the products and by-products obtained from its cultivation. A study of the cultivable bacteria associated with two sunflower cultivars, using classical microbiological methods, successfully obtained isolates from different plant tissues (roots, stems, florets, and rhizosphere). Out of 57 plant-growth-promoting isolates obtained, 45 were identified at the genus level and phylogenetically positioned based on 16S rRNA gene sequencing: 42 Bacillus (B. subtilis, B. cereus, B. thuringiensis, B. pumilus, B. megaterium, and Bacillus sp.) and 3 Methylobacterium komagatae. Random amplified polymorphic DNA (RAPD) analysis showed a broad diversity among the Bacillus isolates, which clustered into 2 groups with 75% similarity and 13 subgroups with 85% similarity, suggesting that the genetic distance correlated with the source of isolation. The isolates were also analyzed for certain growth-promoting activities. Auxin synthesis was widely distributed among the isolates, with values ranging from 93.34 to 1653.37 ${\mu}M$ auxin per ${\mu}g$ of protein. The phosphate solubilization index ranged from 1.25 to 3.89, and siderophore index varied from 1.15 to 5.25. From a total of 57 isolates, 3 showed an ability to biologically fix atmospheric nitrogen, and 7 showed antagonism against the pathogen Sclerotinia sclerotiorum. The results of biochemical characterization allowed identification of potential candidates for the development of biofertilizers targeted to the sunflower crop.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제3권3호
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• pp.149-153
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• 2022

The degree distribution of the plant-pollinator network was identified by analyzing the data in the ecosystem and reproduced by a model of the growing bipartite mutualistic networks. The degree distribution of pollinator shows power law or stretched exponential distribution, while plant usually shows stretched exponential distribution. In the growth model, the plant and the pollinator are selected with probability P_p and P_A=1-P_p, respectively. The number of incoming links for the plant and the pollinator is l_p and l_A, respectively. The probability that the link of the plant selects the pollinator of the existing network given as $A_{k_i}=k^{{\lambda}_A}_i/{\sum}_i\;k^{{\lambda}_A}_i$, and the probability that the pollinator selects the plant is $P_{k_i}=k^{{\lambda}_p}_i/{\sum}_i\;k^{{\lambda}_p}_i$. When the nonlinear growth index is 𝛌_X=1 (X=A or P), the degree distribution follows a power law, and if 0≤𝛌_X<1, the degree distribution follows a stretched exponential distribution. The cumulative degree distributions of plants and pollinators of 14 empirical plant-pollinators included in Interaction Web Database were calculated. A set of parameters (P_A,P_P,l_A,l_P) that reproduces these cumulative degree distributions and a growth index 𝛌_X (X=A or P) were obtained. We found that animal takes very heterogenous connections, whereas plant takes a more flexible connection network.

• 한국환경생태학회지
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• 제36권3호
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• pp.327-337
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• 2022

생태복원은 생태계의 건강성과 지속성에 있어 생물다양성의 손실을 막을 수 있는 좋은 수단으로 인식되어 있으나 식물종 선정에 관한 환경, 생리·생태요인, 복원목표 설정 등 종합이고 객관적인 기준점이 없어 실행에 옮기는데 애로사항이 있다. 이에 전문가 그룹의 의견을 종합하는 델파이 기법을 활용하여 생태복원용 식물종을 선정하는데 필요한 평가지표를 개발하였다. 생태복원 등의 전문가를 대상으로 2회에 걸쳐 38부의 설문조사를 시행하여, 복원 대상지를 내륙과 도서 지역으로 나눠 평가지표의 중요도와 우선순위를 분석했다. 중요도 분석 결과, '자생식물'이라는 평가지표가 내륙과 도서 지역에서 모두 평균 4.9로 가장 높았다. 다음 '종자확보', '증식', 활착률' 순으로 높았다. 내륙의 지표우선순위는 '자생식물', '출현빈도', '활착율', '분포범위', '종자확보'로 도서 지역은 '자생식물', '활착율', '출현빈도', '분포범위', '내성' 순으로 나타났다. 중요도와 우선순위 분석을 수행한 결과 '내륙의 중요도 평균값은 4.1, 우선순위 2.9로 도서지역은 중요도 평균값은 4.2, 우선순위 2.9로 기준을 설정하였다. 생태복원용 식물종 선정의 중요도와 우선순위는 '자생식물'이 중요도와 우선순위가 가장 높은 것으로 나타났다. 다음은 '종자확보', '활착율', '지형', '증식', '내성', '토양조건', '생육특성', '천이초기', '분포범위', '출현빈도', '발아율'이 중요도와 우선순위가 낮은 하위 그룹으로 분류되었다. 가장 낮은 지표는 '천이 최종단계', '천이장기', '천이중기', '뿌리', '번식', '토양', '성상', '기술', '경관', '기후', '발아율'로 구분되었다. 이에, 생태복원용 식물종 선정을 위해 객관적 검증을 통한 생태복원용 자생식물 종 선정을 위한 평가지표로 복원사업에 활용되기를 기대한다.

• 한국작물학회지
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• 제44권2호
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• pp.143-148
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• 1999

Soil moisture condition is an important limiting factor in growth and yield in rice culture. The purpose of this study was to compare the influence on the growth, yield and Quality of rice subjected to soil moisture stress (SMS) at different growth stages. Ajaponica rice cultivar, Dongjinbyeo, was cultured under flooded conditions in a plastic container filled with silty loam soil. The container was subjected to SMS until the initial wilting point (IWP) coincided with about 10% in soil moisture content and about-200 kPa in soil matric potential, and was then irrigated again, at 6 and 5 of main growth stage in 1996 and 1997, respectively. At maturity, the plant height, tiller number, leaf area and top dry weight were decreased more in SMS treatments at the early stage than the late stage. The averaged yield index of SMS to control in both years was lowest at meiosis (62.5%), which primarily resulted from lower percent ripened grain and 1,000 grain weight, and second＇ reduced the spikelet number per panicle and panicle number per hill, and followed at tillering stage (68.5%) which resulted from the lower production in tiller number and top dry matter during and after SMS treatment. The percent-age of read rice in SMS plants varied with the treatment stage as order of lower at meiosis (44.0%), heading (53.9%), panicle initiation (70.1%), tillering (72.1%), ripening (75.8%) and 5 days after transplanting (DAT) (79.0%). Protein content in brown rice was slightly larger in SMS at late growth stage than the control, while the contents of fat and ash differed very little between SMS and control. Contents of Mg and K and Mg/K in brown rice with SMS were lower at some treatment stages such as at ripening or panicle initiation.