Genetic transformation experiments of the different explants from Citrus grandis cv. Changshou Shatian You infected with Agrobacterium rhizogenes were carried out in darkness or in light. The optimizing culture system...Genetic transformation experiments of the different explants from Citrus grandis cv. Changshou Shatian You infected with Agrobacterium rhizogenes were carried out in darkness or in light. The optimizing culture system of Ri T-DNA transformed roots for C. grandis cv. Changshou Shatian You was constructed as follows： After the ventral wounded striations on the single activation cotyledon were inoculated by A. rhizogenes A4 （logarithmic period）, they were cocultured at （25 ±2）℃ in darkness for 25-30 days; some transformed roots were generated from wounded striations of most cotyledons. The genetically transformed ratio is （83 ± 11）%. Axenic Ri T-DNA transformed roots （hairy roots） were harvested after five subcultures. Explants were activated on MT medium. The MS medium was used for subculture of transformed roots. Mass Ri T-DNA transformed roots in which the hormone was produced independently were harvested from this optimizing culture system. White, fresh Ri T-DNA transformed roots were （1.14 ±0.07） cm long, （0.73 ±0.04） mm wide, and the growth direction of transformed roots was negative geotropism.展开更多
As a result of intensifying human activities around the Changshou Reservoir, water environmental quality has declined over the years. Water quality had been monitored from 1999 to 2002. The result indicated that the c...As a result of intensifying human activities around the Changshou Reservoir, water environmental quality has declined over the years. Water quality had been monitored from 1999 to 2002. The result indicated that the concentrations of total nitrogen (TN) and total phosphorus (TP) are high. The concentrations of phosphorus range from {0.037} mg/L to {0.444} mg/L, exceeding the critical value ({0.02} mg/L) for eutrophication. The concentrations of total nitrogen and chlorophyll a range from {0.70} mg/L to {4.18} mg/L and from {1.10} mg/m3 to {61.2} mg/m3, respectively. The eutrophication status of the water body was assessed using the method of integrated nutrition state index, which revealed that all sampling sites were eutrophicated from the year of 2001. About {69.6%} of the annual total nitrogen input and 26% of the annual total phosphorus input originated from the upstreams. The contributions of nitrogen and phosphorus from precipitation to the water body are very small ({0.9%} and {0.3%}, respectively) owing to their low contents ({1.21} mg/L and {0.029} mg/L, respectively). Runoff is the secondarily important input source, which accounts for {19.0%} of the total N input and {47.0%} of the total P input, respectively. Attention should be paid to the aquaculture inputs, whose contributions account for {10.5%} of the total N and {26.6%} of the total phosphorus to the water body, respectively. Nutrient loads are estimated to be 118 gNm{-2}·a{-1} and 8 gPm{-2}·a{-1}. About {69.4%} of nitrogen and {79.7%} of phosphorus input into the reservoir were retained in 2002.展开更多
基金The research was supported by the Science Fund of China Post Ph.D （2003034492）Science Foundation of Chongqing Educational Committee （040216）, China.
文摘Genetic transformation experiments of the different explants from Citrus grandis cv. Changshou Shatian You infected with Agrobacterium rhizogenes were carried out in darkness or in light. The optimizing culture system of Ri T-DNA transformed roots for C. grandis cv. Changshou Shatian You was constructed as follows： After the ventral wounded striations on the single activation cotyledon were inoculated by A. rhizogenes A4 （logarithmic period）, they were cocultured at （25 ±2）℃ in darkness for 25-30 days; some transformed roots were generated from wounded striations of most cotyledons. The genetically transformed ratio is （83 ± 11）%. Axenic Ri T-DNA transformed roots （hairy roots） were harvested after five subcultures. Explants were activated on MT medium. The MS medium was used for subculture of transformed roots. Mass Ri T-DNA transformed roots in which the hormone was produced independently were harvested from this optimizing culture system. White, fresh Ri T-DNA transformed roots were （1.14 ±0.07） cm long, （0.73 ±0.04） mm wide, and the growth direction of transformed roots was negative geotropism.
文摘As a result of intensifying human activities around the Changshou Reservoir, water environmental quality has declined over the years. Water quality had been monitored from 1999 to 2002. The result indicated that the concentrations of total nitrogen (TN) and total phosphorus (TP) are high. The concentrations of phosphorus range from {0.037} mg/L to {0.444} mg/L, exceeding the critical value ({0.02} mg/L) for eutrophication. The concentrations of total nitrogen and chlorophyll a range from {0.70} mg/L to {4.18} mg/L and from {1.10} mg/m3 to {61.2} mg/m3, respectively. The eutrophication status of the water body was assessed using the method of integrated nutrition state index, which revealed that all sampling sites were eutrophicated from the year of 2001. About {69.6%} of the annual total nitrogen input and 26% of the annual total phosphorus input originated from the upstreams. The contributions of nitrogen and phosphorus from precipitation to the water body are very small ({0.9%} and {0.3%}, respectively) owing to their low contents ({1.21} mg/L and {0.029} mg/L, respectively). Runoff is the secondarily important input source, which accounts for {19.0%} of the total N input and {47.0%} of the total P input, respectively. Attention should be paid to the aquaculture inputs, whose contributions account for {10.5%} of the total N and {26.6%} of the total phosphorus to the water body, respectively. Nutrient loads are estimated to be 118 gNm{-2}·a{-1} and 8 gPm{-2}·a{-1}. About {69.4%} of nitrogen and {79.7%} of phosphorus input into the reservoir were retained in 2002.
