EFFECTS OF SPECIFIC ALIEN PLANT LUDWIGIA GRANDIFLORA ON ENDIMIC VEGETATION IN HARIE WETLAND, LAKE BIWA

2020 ◽  
Vol 76 (7) ◽  
pp. III_197-III_204
Author(s):  
Hongwei ZHANG ◽  
Shuhei TANAKA ◽  
Wataru TAKAMI ◽  
Masaki WATABE ◽  
Yasuhiro OSHIMA ◽  
...  
Keyword(s):  
Lake Biwa ◽  
Alien Plant ◽  
Ludwigia Grandiflora

Contribution of large bacteria to bacterial biomass in a deep freshwater lake (Lake Biwa, Japan)

2020 ◽  
Vol 85 ◽  
pp. 131-139
Author(s):  
S Shen ◽  
Y Shimizu
Keyword(s):  
Cell Volume ◽  
Bacterial Cell ◽  
Lake Biwa ◽  
Bacterial Biomass ◽  
Spatial Variations ◽  
Freshwater Lake ◽  
Heterotrophic Nanoflagellates ◽  
Bacterial Productivity ◽  
Transmission Electron ◽  
Seasonal And Spatial Variations

Despite the importance of bacterial cell volume in microbial ecology in aquatic environments, literature regarding the effects of seasonal and spatial variations on bacterial cell volume remains scarce. We used transmission electron microscopy to examine seasonal and spatial variations in bacterial cell size for 18 mo in 2 layers (epilimnion 0.5 m and hypolimnion 60 m) of Lake Biwa, Japan, a large and deep freshwater lake. During the stratified period, we found that the bacterial cell volume in the hypolimnion ranged from 0.017 to 0.12 µm3 (median), whereas that in the epilimnion was less variable (0.016 to 0.033 µm3, median) and much lower than that in the hypolimnion. Additionally, in the hypolimnion, cell volume during the stratified period was greater than that during the mixing period (up to 5.7-fold). These differences in cell volume resulted in comparable bacterial biomass in the hypolimnion and epilimnion, despite the fact that there was lower bacterial abundance in the hypolimnion than in the epilimnion. We also found that the biomass of larger bacteria, which are not likely to be grazed by heterotrophic nanoflagellates, increased in the hypolimnion during the stratified period. Our data suggest that estimation of carbon flux (e.g. bacterial productivity) needs to be interpreted cautiously when cell volume is used as a constant parametric value. In deep freshwater lakes, a difference in cell volume with seasonal and spatial variation may largely affect estimations.

Insecticidal Activities of the Leaf Extract of the Invasive Alien Plant, Chromolaena odorata (L.) (Asteraceae) Against Macrotermes species (Termites)

2019 ◽  
Vol 35 (1) ◽  
pp. 145-153
Author(s):  
O. Uyi, ◽  
I.G. Amolo ◽  
A.D. Adetimehin
Keyword(s):  
Leaf Extract ◽  
Insect Pests ◽  
Chromolaena Odorata ◽  
Leaf Extracts ◽  
Alien Plant ◽  
Biological Efficacy ◽  
Invasive Alien Plant ◽  
Impregnation Technique ◽  
Aqueous Leaf Extract ◽  
Worker Caste

Several studies have demonstrated the biological efficacy of leaf, stem and root powders or extracts of Chromolaena odorata (L.) King and Robinson against insect pests but those that are focused on the biological efficacy of aqueous leaf extracts against Macrotermes species are scanty. Current management of termites with synthetic insecticides is being discouraged due to human and environmental hazards. Therefore, the insecticidal effectiveness of aqueous leaf extract C. odorata against Macrotermes species was investigated. Five concentrations (0, 2.5, 5.0, 7.5 and 10.0% (w/v)) of the aqueous extract of C. odorata plant were evaluated for repellency and toxicity on the worker caste of Macrotermes species following standard procedures. The filter paper impregnation technique was used for the bioassay. Percentage repellency was monitored for 30 minutes and mortality recorded at 12, 24 and 36 hours post exposure. The leaf extract of C. odorata significantly repelled 95% of Macrotermes species at the highest concentration of 10% (w/v) after 30 minutes post treatment exposure. Mortality of Macrotermes species was independent of treatment concentration, but dependent on duration of exposure. All treatment concentrations of aqueous leaf extract of C. odorata caused significant mortality against Macrotermes species ranging between 94% and 98% compared to the control; indicating very great potential for adoption and use in the management of Macrotermes species.

Invasion patterns of seven alien plant species along roadsides in southern mountainous areas of Yunnan Province

2008 ◽  
Vol 16 (4) ◽  
pp. 369 ◽  
Author(s):  
Zhao Jinli ◽  
Ma Youxin ◽  
Zhu Hua ◽  
Li Hongmei ◽  
Li Wenjun ◽  
...  
Keyword(s):  
Plant Species ◽  
Yunnan Province ◽  
Mountainous Areas ◽  
Alien Plant Species ◽  
Alien Plant ◽  
Invasion Patterns
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