Rhododendron simsii（Ericaeae：Rhododendron） has high ornamental value and ecological value.In this study,7 pairs of novel EST-SSR markers were developed from the genomic sequence of R.simsii,and they were used to in...Rhododendron simsii（Ericaeae：Rhododendron） has high ornamental value and ecological value.In this study,7 pairs of novel EST-SSR markers were developed from the genomic sequence of R.simsii,and they were used to investigate the genetic diversity of 32 natural R.simsii samples from Guifeng Mountain,Hubei Province.Results showed that a total of 31 polymorphic bands were amplified with allele number per locus of 4.43.Mean values of heterozygosity（Ho） and expected heterozygosity（He） were 0.679 58 and 0.723 14,respectively.This research will not only enrich the existing SSR database,but also lay a foundation for subsequent studies about molecular marker-assisted breeding,genetic diversity analysis,genetic structure analysis and phylogenetic analysis.展开更多
Microalgal lipids are regarded as main future feedstock of biofuels for its higher efficiency of accumulation and sus- tainable production. In order to investigate the effect of various nitrogen to phosphorus ratios o...Microalgal lipids are regarded as main future feedstock of biofuels for its higher efficiency of accumulation and sus- tainable production. In order to investigate the effect of various nitrogen to phosphorus ratios on cells growth, chlorophyll content and accumulation of lipids in Dunaliella tertiolecta, experiments were carried out in modified microalgal medium with inorganic nitrogen （nitrate-nitrogen） or organic nitrogen （urea-nitrogen） as the sole nitrogen source at initial N：P ratios ranging from 1：1 to 32：1. The favorable N：P of 16：1 in the nitrate-N or urea-N medium yielded the maximum cell density and specific growth rate. Decrease in chlorophyll content were observed at the N：P of 4：1 in both nitrate-N and urea-N cultures. It was also observed that the maximum lipids concentration was obtained at the N：P of 4：1 in both nitrate and urea nutrient medium. The lipid productivity and lipid content of cultures in the urea-N medium at the N：P of 4： lwere markedly higher than those from cultures with other N：P ratios （p〈 0.05）. The results of this work illustrate the possibility that higher ratios of nitrogen to phosphorus have enhancing effect on cells growth of D. tertiolecta. Conversely, higher lipid accumulation is associated with a decrease in chlorophyll content under lower ratios of nitro- gen to phosphorus. The results confirm the hypothesis of this study that a larger metabolic flux has been channeled to lipid accumu- lation in D. tertiolecta cells when the ratios of nitrogen to phosphorus drop below a critical level.展开更多
文摘Rhododendron simsii（Ericaeae：Rhododendron） has high ornamental value and ecological value.In this study,7 pairs of novel EST-SSR markers were developed from the genomic sequence of R.simsii,and they were used to investigate the genetic diversity of 32 natural R.simsii samples from Guifeng Mountain,Hubei Province.Results showed that a total of 31 polymorphic bands were amplified with allele number per locus of 4.43.Mean values of heterozygosity（Ho） and expected heterozygosity（He） were 0.679 58 and 0.723 14,respectively.This research will not only enrich the existing SSR database,but also lay a foundation for subsequent studies about molecular marker-assisted breeding,genetic diversity analysis,genetic structure analysis and phylogenetic analysis.
基金partially supported by Tianjin Marine Revitalization Plan of Science and Technology (No.KJXH2013-16) from Tianjin Oceanic Administration,China
文摘Microalgal lipids are regarded as main future feedstock of biofuels for its higher efficiency of accumulation and sus- tainable production. In order to investigate the effect of various nitrogen to phosphorus ratios on cells growth, chlorophyll content and accumulation of lipids in Dunaliella tertiolecta, experiments were carried out in modified microalgal medium with inorganic nitrogen （nitrate-nitrogen） or organic nitrogen （urea-nitrogen） as the sole nitrogen source at initial N：P ratios ranging from 1：1 to 32：1. The favorable N：P of 16：1 in the nitrate-N or urea-N medium yielded the maximum cell density and specific growth rate. Decrease in chlorophyll content were observed at the N：P of 4：1 in both nitrate-N and urea-N cultures. It was also observed that the maximum lipids concentration was obtained at the N：P of 4：1 in both nitrate and urea nutrient medium. The lipid productivity and lipid content of cultures in the urea-N medium at the N：P of 4： lwere markedly higher than those from cultures with other N：P ratios （p〈 0.05）. The results of this work illustrate the possibility that higher ratios of nitrogen to phosphorus have enhancing effect on cells growth of D. tertiolecta. Conversely, higher lipid accumulation is associated with a decrease in chlorophyll content under lower ratios of nitro- gen to phosphorus. The results confirm the hypothesis of this study that a larger metabolic flux has been channeled to lipid accumu- lation in D. tertiolecta cells when the ratios of nitrogen to phosphorus drop below a critical level.
