Reeds are widely distributed in drought and high salt conditions of northwestern China. Leaf epidermal micromorphology, anatomy, chloroplast ultrastructure and physio-chemical characteristics due to long-term adaptati...Reeds are widely distributed in drought and high salt conditions of northwestern China. Leaf epidermal micromorphology, anatomy, chloroplast ultrastructure and physio-chemical characteristics due to long-term adaptation in the natural habitats of common reed （Phragmites communis Trin.） contrasted considerably among three different ecotypes： dune reed （DR）, Gobi salt reed （GSR） and swamp reed （SR）. The main objective of the present study is to determine the adapting characteristics of morphology, anatomy and physiological responses of thin roots in DR, GSR and SR. The results show that root length density was higher in SR and few root hairs were observed in DR. Cross-section anatomical features show that each ecotype has an endodermis and exodermis, while cortex thickness and proportion of root cortical aerenchyma and stele in root structure varied among the three ecotypes. The stele and xylem share a larger area in DR compared to GSR and SR. GSR has a large proportion of the cortex with radialized distribution of aerenchyma cells spacing, and the cortex has a peripheral, mechanically stiff ring in the exodermis. SEM and TEM microscope images show that GSR has a scle- renchyma ring with high lignification in the exodermis. The physio-chemical parameters show that GSR had a higher level of stress tolerance than DR. These findings indicate that developed water-absorbing tissues were largely distributed in the root structure of DR, and a main framework with supporting function spacing with aerenchyma was dominant in GSR in the long term adaptation to their natural habitats, respectively.展开更多
In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed...In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.展开更多
To compare differential gene expression among three ecotypes of reed (Phragmites communis Trin.), dune reed (DR), heavy-salt meadow reed (HSR) and light-salt meadow reed (LSR), mRNA transcripts were displayed by cDNA-...To compare differential gene expression among three ecotypes of reed (Phragmites communis Trin.), dune reed (DR), heavy-salt meadow reed (HSR) and light-salt meadow reed (LSR), mRNA transcripts were displayed by cDNA-AFLP (amplified fragment length polymorphisms). The result revealed that a relatively small number of genes are likely involved in adaptations of DR and HSR to stresses. A full-length cDNA encoding dTDP-D-glucose dehydratase gene (PcTGD) was subsequently cloned from DR. Northern blot analysis showed that it is highly expressed in stem as well as rhizoma of the three ecotypes. However, its expression in DR stem was much higher than that of the other two ecotypes. After the removal of water stress, the expression of PcTGD was significantly reduced, suggesting that it possibly plays a role in adaptation of DR to water stress through an osmotic regulation mechanism.展开更多
A small solute has been obtained with column chromatography, which only exists and accumulates in the leaves of dune reed in northwest China’s desert region. Its unique polyamine and aromatic features are quite diffe...A small solute has been obtained with column chromatography, which only exists and accumulates in the leaves of dune reed in northwest China’s desert region. Its unique polyamine and aromatic features are quite different from those well-known ones accumulated under stresses. The natural quantity of the solute is strikingly proportional to the level of local high temperature, and a large section is distributed in the photosynthetic chloroplasts. Under lab conditions, we have proved that the solute plays a role in protecting or conserving chloroplasts under heat stress. So it is reasonable to suppose that the high resistance of dune reed to environmental high temperature and/or drought is at least partially due to the accumulation of this unique solute.展开更多
用便携式L I-6400光合测定仪,在晴朗的天气,对芦苇成熟叶片净光合速率(Pn)以及光合有效辐射(Par)、气孔导度(G s)、细胞间CO2浓度(C i)、叶温(T l)、叶周围气温(T a)和蒸腾速率(T r)等影响因子进行田间测定,研究芦苇的光合日变化。结果...用便携式L I-6400光合测定仪,在晴朗的天气,对芦苇成熟叶片净光合速率(Pn)以及光合有效辐射(Par)、气孔导度(G s)、细胞间CO2浓度(C i)、叶温(T l)、叶周围气温(T a)和蒸腾速率(T r)等影响因子进行田间测定,研究芦苇的光合日变化。结果表明:芦苇净光合速率日变化呈双峰曲线,主峰出现在10:00,次峰出现在15:00,光合“午休”现象明显,且气孔限制是产生“午休”的主要原因。净光合速率日均为20.01μm o l.m-2.s-1,蒸腾速率日均为6.15 mm o l.m-2.-s 1,光补偿点为98μm o l.m-2.-s 1,光饱和点为2 125μm o l.m-2.-s 1(自然状态下达不到),表观光量子效率为0.060 4 m o l.m o-l 1,暗呼吸速率为2.91μm o l.m-2.-s 1,CO2补偿点为53μm o l.m o-l 1,饱和点为1 368μm o l.m o-l 1,羧化效率为0.064 7。数据显示,芦苇是一种高光效阳性植物,对于其资源的合理利用及其对湿地生态系统的稳定意义重大。展开更多
基金financially supported by the State Key Development Program for Basic Research of China(973 Program,Grant No.2013CB429904)the National Natural Science Foundation of China(Grant No.91125029)
文摘Reeds are widely distributed in drought and high salt conditions of northwestern China. Leaf epidermal micromorphology, anatomy, chloroplast ultrastructure and physio-chemical characteristics due to long-term adaptation in the natural habitats of common reed （Phragmites communis Trin.） contrasted considerably among three different ecotypes： dune reed （DR）, Gobi salt reed （GSR） and swamp reed （SR）. The main objective of the present study is to determine the adapting characteristics of morphology, anatomy and physiological responses of thin roots in DR, GSR and SR. The results show that root length density was higher in SR and few root hairs were observed in DR. Cross-section anatomical features show that each ecotype has an endodermis and exodermis, while cortex thickness and proportion of root cortical aerenchyma and stele in root structure varied among the three ecotypes. The stele and xylem share a larger area in DR compared to GSR and SR. GSR has a large proportion of the cortex with radialized distribution of aerenchyma cells spacing, and the cortex has a peripheral, mechanically stiff ring in the exodermis. SEM and TEM microscope images show that GSR has a scle- renchyma ring with high lignification in the exodermis. The physio-chemical parameters show that GSR had a higher level of stress tolerance than DR. These findings indicate that developed water-absorbing tissues were largely distributed in the root structure of DR, and a main framework with supporting function spacing with aerenchyma was dominant in GSR in the long term adaptation to their natural habitats, respectively.
文摘In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.
基金This work was supported by the State Basic Research Program (Grant No. G1999011705) and the National NaturalScience Foundation of China (Grant No. 39870062).
文摘To compare differential gene expression among three ecotypes of reed (Phragmites communis Trin.), dune reed (DR), heavy-salt meadow reed (HSR) and light-salt meadow reed (LSR), mRNA transcripts were displayed by cDNA-AFLP (amplified fragment length polymorphisms). The result revealed that a relatively small number of genes are likely involved in adaptations of DR and HSR to stresses. A full-length cDNA encoding dTDP-D-glucose dehydratase gene (PcTGD) was subsequently cloned from DR. Northern blot analysis showed that it is highly expressed in stem as well as rhizoma of the three ecotypes. However, its expression in DR stem was much higher than that of the other two ecotypes. After the removal of water stress, the expression of PcTGD was significantly reduced, suggesting that it possibly plays a role in adaptation of DR to water stress through an osmotic regulation mechanism.
文摘A small solute has been obtained with column chromatography, which only exists and accumulates in the leaves of dune reed in northwest China’s desert region. Its unique polyamine and aromatic features are quite different from those well-known ones accumulated under stresses. The natural quantity of the solute is strikingly proportional to the level of local high temperature, and a large section is distributed in the photosynthetic chloroplasts. Under lab conditions, we have proved that the solute plays a role in protecting or conserving chloroplasts under heat stress. So it is reasonable to suppose that the high resistance of dune reed to environmental high temperature and/or drought is at least partially due to the accumulation of this unique solute.
文摘用便携式L I-6400光合测定仪,在晴朗的天气,对芦苇成熟叶片净光合速率(Pn)以及光合有效辐射(Par)、气孔导度(G s)、细胞间CO2浓度(C i)、叶温(T l)、叶周围气温(T a)和蒸腾速率(T r)等影响因子进行田间测定,研究芦苇的光合日变化。结果表明:芦苇净光合速率日变化呈双峰曲线,主峰出现在10:00,次峰出现在15:00,光合“午休”现象明显,且气孔限制是产生“午休”的主要原因。净光合速率日均为20.01μm o l.m-2.s-1,蒸腾速率日均为6.15 mm o l.m-2.-s 1,光补偿点为98μm o l.m-2.-s 1,光饱和点为2 125μm o l.m-2.-s 1(自然状态下达不到),表观光量子效率为0.060 4 m o l.m o-l 1,暗呼吸速率为2.91μm o l.m-2.-s 1,CO2补偿点为53μm o l.m o-l 1,饱和点为1 368μm o l.m o-l 1,羧化效率为0.064 7。数据显示,芦苇是一种高光效阳性植物,对于其资源的合理利用及其对湿地生态系统的稳定意义重大。
