[Objective] Surveys of phytoplankton were taken during the autumn of 2009 along Anhui-Jiangsu reaches of the Yangtze River to understand the species com- position and their spatial distributions. [Method] Phytoplankto...[Objective] Surveys of phytoplankton were taken during the autumn of 2009 along Anhui-Jiangsu reaches of the Yangtze River to understand the species com- position and their spatial distributions. [Method] Phytoplankton species, their quanti- ties, biomass and the Mcnaughton＇s dominance indices were all measured and their spatial distribution characteristics were determined using cluster analysis. [Result] There were 27 species, belonging to 5 phyla, namely Chlorophyta, Bacillariophyta, Cyanophyta, Euglenophyta and Cryptophyta, of phytoplankton collected and identified from the surveys. Results showed that Bacillariophyta was the predominant phyto- plankton with 16 species collected which accounted for 59.3% of the total species identified. The number of species collected belonging to Chlorophyta, Cyanophyta, Cryptophyta and Euglenophyta were 6, 2, 2, and 1, accounting for 22.2%, 7.4%, 7.4% and 3.7% of the total number identified, respectively. At the species level, the predominant species were Fragilaria crotonensis, Melosira italica, Navicula crypto- cephala, Cyclotella striata and Chroomonas acuta. Phytoplankton abundance was ranging from 5.68×10^4 to 7.08×10^4 cells/L with its average of 6.01×10^4 cells/L. Phyto- plankton biomass was ranging from 30.43 to 34.73 μg/L with its average of 32.46 μg/L. Compared with the previous reports, the number of phytoplankton species was decreased but its abundance and biomass was increased along the Jiangsu reach of the Yangtze River. However, Bacillariophyta species were still the predominant species and the phytoplankton community structure had not significantly changed from the previous studies. [Conclusion] These results might be explained as that the water quality in the Yangtze River was deteriorated but had not come to the worst. The results of similarity analysis gave two clusters of phytoplankton community as Nanjing, Wuhu and Jiangyin sampling sites were clustered into one group and Tongling and Anqing were clustered into another group.展开更多
[Objective] To study the cocoon traits of wild silkworm descendants. [Method] In the selective breeding of domesticated raising wild silkworm and wild silkworm descendants, investigation on the traits of the built coc...[Objective] To study the cocoon traits of wild silkworm descendants. [Method] In the selective breeding of domesticated raising wild silkworm and wild silkworm descendants, investigation on the traits of the built cocoons was carried out. [Result] The pointed traits of cocoons displayed obviously in the wild silkworm descendants, its pointed parts were consistent with the rear part of silkworm chrysalis, and the female silkworm has slight difference, indicating the silkworm co- coon pointed trait was hereditary. [Conclusion] This study provided references for the study of silkworm cocoon traits of wild silkworm descendant and guides the selective breeding of silkworm variety.展开更多
To explore the spatial heterogeneity of plankton communities in a deep artificial lake （Songhua Lake, China）, samples were collected at seven sites. Samples were investigated by denaturing gradient gel electrophores...To explore the spatial heterogeneity of plankton communities in a deep artificial lake （Songhua Lake, China）, samples were collected at seven sites. Samples were investigated by denaturing gradient gel electrophoresis （DGGE） analysis of the PCR-amplified 16S and 18S rRNA genes and specific bands were sequenced. Cluster analysis of the DGGE profiles revealed that all of the samples grouped into two distinct clusters, in accordance with sampling site; while in each cluster, the divergence of sub-clusters correlated with sampling depth. Sequence analysis of selected dominant DGGE bands revealed that most sequenced phylotypes （84%） exhibited 〉97% similarity to the closest sequences in GenBank, and were affiliated with ten common freshwater plankton phyla （Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Bacillariophyta, Pyrrophyta, Cryptophyta, Ciliophora, Stramenopiles, and Rotifera）. Several of these groups are also found worldwide, indicating the cosmopolitan distribution of the phylotypes. The relationships between DGGE patterns and environmental factors were analyzed by redundancy analysis （RDA）. The results suggested that, total nitrogen, nitrate, nitrite, temperature were strongly correlated with the variation ammonia, and CODMn concentrations, and water in plankton composition.展开更多
基金Supported by Fishery Germplasm Conservation Project of the Ministry of Agriculture(MOA)(No.6115048)State Specific Project on Fundamental Scientific Research Financed to Public Institutes(No.2009JBFB10)~~
文摘[Objective] Surveys of phytoplankton were taken during the autumn of 2009 along Anhui-Jiangsu reaches of the Yangtze River to understand the species com- position and their spatial distributions. [Method] Phytoplankton species, their quanti- ties, biomass and the Mcnaughton＇s dominance indices were all measured and their spatial distribution characteristics were determined using cluster analysis. [Result] There were 27 species, belonging to 5 phyla, namely Chlorophyta, Bacillariophyta, Cyanophyta, Euglenophyta and Cryptophyta, of phytoplankton collected and identified from the surveys. Results showed that Bacillariophyta was the predominant phyto- plankton with 16 species collected which accounted for 59.3% of the total species identified. The number of species collected belonging to Chlorophyta, Cyanophyta, Cryptophyta and Euglenophyta were 6, 2, 2, and 1, accounting for 22.2%, 7.4%, 7.4% and 3.7% of the total number identified, respectively. At the species level, the predominant species were Fragilaria crotonensis, Melosira italica, Navicula crypto- cephala, Cyclotella striata and Chroomonas acuta. Phytoplankton abundance was ranging from 5.68×10^4 to 7.08×10^4 cells/L with its average of 6.01×10^4 cells/L. Phyto- plankton biomass was ranging from 30.43 to 34.73 μg/L with its average of 32.46 μg/L. Compared with the previous reports, the number of phytoplankton species was decreased but its abundance and biomass was increased along the Jiangsu reach of the Yangtze River. However, Bacillariophyta species were still the predominant species and the phytoplankton community structure had not significantly changed from the previous studies. [Conclusion] These results might be explained as that the water quality in the Yangtze River was deteriorated but had not come to the worst. The results of similarity analysis gave two clusters of phytoplankton community as Nanjing, Wuhu and Jiangyin sampling sites were clustered into one group and Tongling and Anqing were clustered into another group.
基金Supported by the Agricultural Fund Project of Ministry of Science and Technology(Y0415)the China Agriculture Research System(Sericulture)~~
文摘[Objective] To study the cocoon traits of wild silkworm descendants. [Method] In the selective breeding of domesticated raising wild silkworm and wild silkworm descendants, investigation on the traits of the built cocoons was carried out. [Result] The pointed traits of cocoons displayed obviously in the wild silkworm descendants, its pointed parts were consistent with the rear part of silkworm chrysalis, and the female silkworm has slight difference, indicating the silkworm co- coon pointed trait was hereditary. [Conclusion] This study provided references for the study of silkworm cocoon traits of wild silkworm descendant and guides the selective breeding of silkworm variety.
基金Supported by the National Natural Science Foundation of China(No.51178090)the National Key Technology R&D Program of China(No.2012BAJ21B02-02)the National Water Pollution Control and Management Technology Major Projects(No.2009ZX07106-001)
文摘To explore the spatial heterogeneity of plankton communities in a deep artificial lake （Songhua Lake, China）, samples were collected at seven sites. Samples were investigated by denaturing gradient gel electrophoresis （DGGE） analysis of the PCR-amplified 16S and 18S rRNA genes and specific bands were sequenced. Cluster analysis of the DGGE profiles revealed that all of the samples grouped into two distinct clusters, in accordance with sampling site; while in each cluster, the divergence of sub-clusters correlated with sampling depth. Sequence analysis of selected dominant DGGE bands revealed that most sequenced phylotypes （84%） exhibited 〉97% similarity to the closest sequences in GenBank, and were affiliated with ten common freshwater plankton phyla （Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Bacillariophyta, Pyrrophyta, Cryptophyta, Ciliophora, Stramenopiles, and Rotifera）. Several of these groups are also found worldwide, indicating the cosmopolitan distribution of the phylotypes. The relationships between DGGE patterns and environmental factors were analyzed by redundancy analysis （RDA）. The results suggested that, total nitrogen, nitrate, nitrite, temperature were strongly correlated with the variation ammonia, and CODMn concentrations, and water in plankton composition.
