• 한국물환경학회지
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• 제33권5호
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• pp.538-545
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• 2017

The purpose of this study is to investigate growth response and toxigenicity under various temperature and nutritional conditions, in order to understand the physioecological characteristics of Aphanizomenon flos-aquae, which is a bloom-forming cyanobacterium in the Nakdong River. The strain was inoculated into media under combinations of four temperatures (4, 12, 21, $30^{\circ}C$) and three nutrients (modified CB medium, P-depleted CB medium, N-depleted CB medium) for 28 days. The algae-inhibition tests were performed to assess the potential allelopathic effects of the strains' filtrates on the growth of four algae strains (Microcystis aeruginosa, Aulacoseria ambigua f. spiralis, Aphanizomenon flos-aquae, Scenedesmus obliquus). Toxin production of a strain was measured by Enzyme-Linked ImmunoSolbent Assay (ELISA). The optimal growth temperature (Topt) of strains was $19.9^{\circ}C$ ($18.3-21.2^{\circ}C$), and the temperature range for growth was from $-0.3^{\circ}C$ to $34.3^{\circ}C$. Specific growth rate (${\mu}$) in modified CB medium varied from 0.10 to $0.16day^{-1}$, and the maximum growth rate (${\mu}_{max}$) was $0.17day^{-1}$. Although growth curves under N-existed and N-depleted conditions were almost the same, growth under N-depleted condition was relatively slowed (${\mu}=0.09$ to $0.14day^{-1}$), with a decreased maximum cell density. However, growth under the P-depleted condition was restricted for all temperatures, Two stains of Aphanizomenon flos-aquae were confirmed as not producing toxins, because saxitoxin and cylindrospermopsin were not detected by ELISA. The exudates or filtrates from the Aphanizomenon flos-aquae (DGUC003) resulted in significant inhibition of algal growth on the Aulacoseira ambigua f. spiralis (DGUD001) and Aphanizomenon flos-aquae (DGUC001) (p < 0.01).

• 한국잔디학회:학술대회논문집
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• 한국잔디학회 2002년도 제15차 한국잔디학회 정기총회 및 춘계학술발표회
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• pp.3-5
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• 2002

This study was carried out to get better understandings about morphological, ecological, and genetical characteristics of annual bluegrass collected from different golf courses in Korea and eventually to establish a successful control strategy. Twenty five local lines of annual bluegrass collected from 20 golf courses in Korea were classified into annual or perennial type on the basis of morphological characteristics. Twelve local lines showing obvious morphological differences were selected and then genetically assessed using RAPD analysis. Classification of the 12 local lines through RAPD analysis were considerably similar to that determined by both of morphological differences and phenotype. Responses of the two types of annual blugrass to herbicides were also examined. Shoot growth of annual bluegrass was significantly suppressed by flazasulfuron and the annual type was more susceptible than perennial type, regardless of flazasulfuron concentrations used. By pendimethalin treatment, there was no clear difference in susceptibility between the two types of annual bluegrass. However, by the treatment of dithiopyr, annual type was more sensitive than perennial type in both shoot and root growth. Nine tree species were screened to detect their allelopathic potential on turfgrasses and annual bluegrass. Acacia (Robinia pseudo-acacia) leaves showed selective inhibition in the shoot and root growth as well as their seed germination when treated with 2% and 10%(v/v) of the extract. However, the other leaf extracts except acacia inhibited non-selectively the growth of three turfgrass species such as bentgrass, perennial ryegrass and zoysiagrass and annual bluegrass. The PAL activities of annual bluegrass increased at 24 h after treatment of acacia leaf extract and peaked at 36 h and then decreased till 60h. The highest PAL activity was observed at 36h after treatment of 10%. The highest activity of CA4H in annual bluegrass was observed at 2h after treatment of acacia extract and the level was 4 times greater than that of the control. The phenolic acids such as p-coumaric acid, salicylic acid and ferulic acid were increased with the treatment of acacia leaf extract. The chloroplast membrane and cell wall of annual bluegrass were destroyed by treatment of acacia leaf extract and its inner materials were released. The membranes in annual bluegrass cells might be destroyed by phytotoxic compounds from acacia leaf extract.

• 한국수산과학회지
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• 제57권4호
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• pp.389-396
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• 2024

Reactive oxygen species (ROS) generated by harmful algal blooms (HABs) exert detrimental effects on aquaculture systems. Fish gill cells deteriorate upon exposure to HABs, suggesting that internally generated ROS in HABs influences the external environment. Therefore, we investigated the internal and external changes in ROS concentrations during growth using fluorescence staining of four representative HABs: Alexandrium affine, Chattonella marina, Karenia mikimotoi, and Margalefidinium polykrikoides. The concentrations of H₂O₂ and O₂^- produced by A. affine were low; H₂O₂ from M. polykrikoides was primarily detected internally throughout the experiments, and O₂^- was not detected. High H₂O₂ and O₂^- concentrations were observed in K. mikimotoi during the death phase, with weak external O₂^- concentrations. Regarding C. marina, which produces large amounts of ROS, H₂O₂ was observed internally during the exponential phase, whereas weak O₂^- concentrations were measured externally in the stationary phases. Collectively, our results highlight that ROS concentrations and internal/external distributions are functions of HABs and growth stage. These differences indicate the potential allelopathic mechanisms of proliferating HABs and suggest a possible impact of ROS on aquaculture organisms.

• 한국잡초학회지
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• 제31권2호
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• pp.175-182
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• 2011

헤어리벳베치 잔류물의 제초효과와 작물안전성에 미치는 영향을 연구하기 위하여 헤어리벳치 잔류물을 온실, 비닐하우스 및 포장조건에서 복토처리하여 실험을 수행하였다. 온실조건에서 헤어리벳치와 토양(60:40) 혼합처리에서 90% 이상 방제효과를 나타냈으며 90:10 혼합비율에서는 100% 고사되었다. 제초효과는 일반적으로 화본과잡초에 비해 광엽잡초에서 높은 경향을 나타났다. 헤어리벳치 잔류물은 비닐하우스에서는 갈퀴덩굴, 명아주, 질경이와 소리쟁이에서 우수한 제초효과를 보였고, 포장조건에서는 갈퀴덩굴, 소리쟁이와 털비름에서 제초효과가 높았다. 헤어리벳치 혼합비물(60:40)을 0.5~0.75cm 깊이로 복토하였을 때 비닐하우스와 포장조건에서 약 80% 이상의 제초효과를 나타냈다. 헤어리벳치 잔류물은 상추를 제외한 옥수수, 콩, 무, 고추, 배추, 오이, 토마토, 들깨에서 모두 작물의 생장에 영향이 없었다.