Li Q.,Guangxi University |
Zhou M.,Guangxi University |
Liu Y.,Guangxi University |
Liu Y.,Guangxi Key Laboratory of Biorefining |
And 4 more authors.
Huagong Xuebao/CIESC Journal | Year: 2013
The immobilization of Pseudomonas aeruginosa GF31 and its enhancement of biodegradation of cypermethrin were investigated. Zeolite was chosen as a suitable support for the immobilization by taking into account the properties of cypermethrin and mass transfer in the bioremediation. Scanning electron microscope(SEM) images demonstrated that strain GF31 grew well in the pore of the zeolite. After immobilization, cypermethrin removal efficiency was improved significantly from 37% to 61.4% at initial cypermethrin concentration of 100 mg ·L-1 in 6 d. The specific degradation rate of free cells and immobilized cells were 487 and 917 mg·[L·d·(g dry biomass)]-1 respectively, at 300 mg·L-1 cypermethrin. It was also found that the immobilized cells exhibited higher tolerance to pH and cypermethrin concentration, keeping its activities even at pH 10 or higher cypermethrin concentration up to 800 mg·L-1. The results of actual soil remediation by the immobilized cells showed that cypermethrin degradation could be well described by a first-order reaction rate equation. As compared to natural degradation, cypermethrin half life(t1/2) was shortened from 34.3 d to 8.02 d, which illustrated a good result of bioaugmented remediation by the immobilized Pseudomonas aeruginosa GF31.
He H.,Guangxi Meteorological Disaster Mitigation Institute |
He Y.,Guangxi Meteorological Disaster Mitigation Institute |
Meng C.,Guangxi Meteorological Disaster Mitigation Institute |
Long M.,Plant Protection Station of Guangxi |
And 2 more authors.
Journal of Natural Disasters | Year: 2014
Based on data of 60 agricultural survey stations during 1988 to 2010, the spatiotemporal characteristics of rice planthoppers occurrence degree in Guangxi Province were studied by methods of EOF, trend coefficients, linear trend and M-K test, etc. Results show that, on the whole, occurrence degree of rice planthoppers is higher for the first half year than for the second half year, and is higher in east than in west of Guangxi. The occurrence degrees in both sequential half years have increased in the past 23 years, but it is more obvious for the second half year. As for the spatial change characteristics change of rice planthoppers occurrence degree in Guangxi, the region is divided into three sub-regions, because rice planthoppers occurrence may relate to climate difference for different sub-regions. In the first half year, a significant upward trend of occurrence degree appeared in northwest Guangxi, and a remarkable abrupt increase occurred in 1994. But the trends were not significant in neither southwest nor east. For the second half year, the rice planthoppers occurrence degree in both northwest and northeast show significant upward trends, and remarkable abrupt changes of increase occurred in 2006 and in 1998, respectively, but the trend of south was not significant.
He Y.,Guangxi Meteorological Disaster Mitigation Institute Remote Sensing Application and Experiment Station of National Satellite Meteorological Center |
Meng C.-L.,Guangxi Meteorological Disaster Mitigation Institute Remote Sensing Application and Experiment Station of National Satellite Meteorological Center |
Xie M.-C.,Plant Protection Station of Guangxi |
Long M.-L.,Plant Protection Station of Guangxi |
Li Y.-H.,Guangxi Meteorological Disaster Mitigation Institute Remote Sensing Application and Experiment Station of National Satellite Meteorological Center
Chinese Journal of Ecology | Year: 2014
Based on data of occurrence degree of rice planthoppers from 45 agricultural pest monitoring stations in Guangxi Province during 1988 to 2012 as well as data of meteorological factors and atmospheric circulation characteristics during 1987 to 2012, three zones with different occurrence degrees of early rice planthoppers were divided: east Guangxi, southwest Guangxi, and northwest Guangxi. Occurrence degree of early rice planthoppers was predicted in each zone by fuzzy cluster analysis, and BP neural network. The results showed that the occurrence degree of rice planthoppers was closely correlated with meteorological factors and atmospheric general circulation in Guangxi. High temperature, frequent rainy days, high humidity and insufficient sunshine in winter and spring seasons were beneficial to the occurrence of rice planthoppers, and subtropical high, India-Burma trough and southwest airflow also affected the occurrence degree of rice planthoppers. Original predictive factors for the occurrence degree of early rice planthoppers in each zone were selected from the meteorological factors in winter and spring seasons and the atmospheric circulation characteristics to build comprehensive predictors using EOF decomposition method, and then prediction models for the occurrence degree of rice planthoppers were established in each zone. The cross-test showed that the average absolute fitting error was lower in BP neural network model than in step regression by 0. 07 in east Guangxi, 0. 1 in southwest Guan-gxi, and 0. 02 in northwest Guangxi. The prediction using independent-samples in 2011 to 2012 showed that the mean predicted absolute errors were 0. 42 for BP neural network model and 0. 5 for step regression, indicating that the nonlinear correlation between rice planthoppers and meteorological factors is better predicted by BP neural network model. © 2014, Editorial Board of Chinese Journal of Ecology. All rights reserved.