Wild cotton species can contribute a valuable gene pool for agronomically desirable cultivated tetraploid cultivars. In order to exploit diploid cotton a regeneration system is required to achieve transformation based...Wild cotton species can contribute a valuable gene pool for agronomically desirable cultivated tetraploid cultivars. In order to exploit diploid cotton a regeneration system is required to achieve transformation based goals. The present studies aimed at optimizing the conditions for regeneration of local varieties as well as wild species of cotton. Different callus induction media were tested with varying concentrations of hormones in which sucrose was used as nutritional source. Different explants (hypo-cotyls, cotyledon, root) were used to check the regeneration of both local cotton plants and wild relatives using T & G medium, BAP medium, CIM medium, EMMS medium, and cell suspension medium. Different stages of embryogenicity such as early torpedo stage, late torpedo stage, heart stage, globular stage and cotyledonary stage were observed in wild relatives of cotton. The results of this study pave the way for establishing future transformation methods.展开更多
To study the relationship between zooplankton community structure and environmental factors and water quality in the Harbin Section of the Songhua River,investigations were carried out in June,August,and October 2011....To study the relationship between zooplankton community structure and environmental factors and water quality in the Harbin Section of the Songhua River,investigations were carried out in June,August,and October 2011.Canonical correspondence analysis(CCA) and saprobic indices were used to process and analyze the data.Seasonal variability was identified as a significant source of variation,which explains the fluctuation in zooplankton density.In autumn,the dry season,water residence time increased and zooplankton biomass and abundance accumulated in the slow flowing waters.Zooplankton abundance increased when food conditions improved.Therefore,the total zooplankton abundance in autumn is much higher than that in spring and summer.According to the saprobic indices,all the sample sites had mesosaprobic water and water quality was worse in autumn.CCA revealed that temperature accounted for most of the spatial variation in the zooplankton community.Moreover,pH,dissolved oxygen saturation,and turbidity were important factors affecting zooplankton community distribution.展开更多
文摘Wild cotton species can contribute a valuable gene pool for agronomically desirable cultivated tetraploid cultivars. In order to exploit diploid cotton a regeneration system is required to achieve transformation based goals. The present studies aimed at optimizing the conditions for regeneration of local varieties as well as wild species of cotton. Different callus induction media were tested with varying concentrations of hormones in which sucrose was used as nutritional source. Different explants (hypo-cotyls, cotyledon, root) were used to check the regeneration of both local cotton plants and wild relatives using T & G medium, BAP medium, CIM medium, EMMS medium, and cell suspension medium. Different stages of embryogenicity such as early torpedo stage, late torpedo stage, heart stage, globular stage and cotyledonary stage were observed in wild relatives of cotton. The results of this study pave the way for establishing future transformation methods.
基金Supported by the National Natural Science Foundation of China(No.41271106)
文摘To study the relationship between zooplankton community structure and environmental factors and water quality in the Harbin Section of the Songhua River,investigations were carried out in June,August,and October 2011.Canonical correspondence analysis(CCA) and saprobic indices were used to process and analyze the data.Seasonal variability was identified as a significant source of variation,which explains the fluctuation in zooplankton density.In autumn,the dry season,water residence time increased and zooplankton biomass and abundance accumulated in the slow flowing waters.Zooplankton abundance increased when food conditions improved.Therefore,the total zooplankton abundance in autumn is much higher than that in spring and summer.According to the saprobic indices,all the sample sites had mesosaprobic water and water quality was worse in autumn.CCA revealed that temperature accounted for most of the spatial variation in the zooplankton community.Moreover,pH,dissolved oxygen saturation,and turbidity were important factors affecting zooplankton community distribution.
