Naturally occurring floods in the summer months are the main source of surface water application in the foreland of Qira oasis, which is characterized by a hyperarid climate and is located at the southern fringe of th...Naturally occurring floods in the summer months are the main source of surface water application in the foreland of Qira oasis, which is characterized by a hyperarid climate and is located at the southern fringe of the Taklimakan Desert. We investigated the impact of repeated artificial flood irrigation on seedling recruitment and growth of Alhagi sparsifolia and Karelinia caspica plant communities which are part of the dominant vegetation in Qira oasis. Flood irrigation was applied three times during the growing season and we studied the effect of irrigation on species recruitment, vegetation growth, spe- cies composition, and changes in soil water and nutrient concentrations in the soil profile. Results show that (1) repeated flood irrigation had a positive effect on seedling recruitment of the two species, with vegetative recruitment via root tillers being more important than seed recruitment for both species. (2) Irrigation promoted the germination and establishment of herbaceous weed species, which in- creased species diversity as well as ground coverage. (3) Irrigation also increased soil water and soil nutrient concentrations in the upper soil layer and changed the soil nutrients in the vertical profile. Available N, P, K and the total P and K increased in the soil profile. Our study demonstrates that naturally occurring flood irrigation has significant ecological benefits and plays an important role in promoting the renewal of desert vegetation and a short-term increase of soil nutrients. Our study also highlights the potential negative consequences for vegetation composition and rejuvenation if naturally occurring floods in the study area are diminished by either the effects of climate change or human management.展开更多
This paper focused on the water relations of two halophytes differing in photosynthetic pathway, phe- notype, and life cycle： Karelinia caspica （Pall.） Less. （C3, deep-rooted perennial Asteraceae grass） and Atrip...This paper focused on the water relations of two halophytes differing in photosynthetic pathway, phe- notype, and life cycle： Karelinia caspica （Pall.） Less. （C3, deep-rooted perennial Asteraceae grass） and Atriplex tatarica L. （C4, shallow-rooted annual Chenopodiaceae grass）. Gas exchange, leaf water potential, and growth characteristics were investigated in two growing seasons in an arid area of Xinjiang to explore the physiological adaptability of the two halophytes. Both K. caspica and A. tatarica showed midday depression of transpiration, in- dicating that they were strong xerophytes and weak midday depression types. The roots of A. tatarica were con- centrated mainly in the 0-60 cm soil layer, and the leaf water potential （~L） increased sharply in the 0-20 cm layer due to high soil water content, suggesting that the upper soil was the main water source. On the other hand, K. caspica had a rooting depth of about 1.5 m and a larger root/shoot ratio, which confirmed that this species uptakes water mainly from deeper soil layer. Although A. tatarica had lower transpiration water consumption, higher water use efficiency （WUE）, and less water demand at the same leaf water potential, it showed larger water stress impact than K. caspica, indicating that the growth of A. tatarica was restricted more than that of K. caspica when there was no rainfall recharge. As a shallow-rooted C4 species, A. tatarica displayed lower stomatal conductance, which could to some extent reduce transpiration water loss and maintain leaf water potential steadily. In contrast, the deep-rooted C3 species K. caspica had a larger root/shoot ratio that was in favor of exploiting groundwater. We concluded that C3 species （K. caspica） tapes water and C4 species （A. tatarica） reduces water loss to survive in the arid and saline conditions. The results provided a case for the phenotype theory of Schwinning and Ehleringer on halophytic plants.展开更多
盐穗木是一种理想的耐盐模式植物,本文利用生物信息学方法分析盐穗木在盐胁迫下差异表达基因的转录组,为盐穗木耐盐机理及耐盐关键基因的储备提供理论依据。基于盐穗木在盐胁迫(600 mM NaCl)下差异表达的转录组数据,以代谢通路中基因表...盐穗木是一种理想的耐盐模式植物,本文利用生物信息学方法分析盐穗木在盐胁迫下差异表达基因的转录组,为盐穗木耐盐机理及耐盐关键基因的储备提供理论依据。基于盐穗木在盐胁迫(600 mM NaCl)下差异表达的转录组数据,以代谢通路中基因表达数量最多的7条通路和与胁迫刺激响应相关的共8条通路为主要研究内容,筛选出上调和下调表达差异显著的unigene,将其与NCBI数据库中所有物种相关基因进行Blastx比对,筛选出通路中上调和下调差异表达最显著的unigene,同时对差异表达活跃的unigene进行分类汇总。共得到23组差异表达活跃的基因类群,分别是乙烯响应因子、WRKY转录因子、Myb转录因子、bZIP转录因子、葡聚糖酶、6-磷酸脱氢酶、醛脱氢酶、柠檬酸合成酶、蛋白激酶等,推测这些类群的基因在盐穗木耐盐机制中发挥重要作用。展开更多
基金Supported by National Natural Science Foundation of China (Grant No. 30670386)Station Foundation of Chinese Academy of Sciences
文摘Naturally occurring floods in the summer months are the main source of surface water application in the foreland of Qira oasis, which is characterized by a hyperarid climate and is located at the southern fringe of the Taklimakan Desert. We investigated the impact of repeated artificial flood irrigation on seedling recruitment and growth of Alhagi sparsifolia and Karelinia caspica plant communities which are part of the dominant vegetation in Qira oasis. Flood irrigation was applied three times during the growing season and we studied the effect of irrigation on species recruitment, vegetation growth, spe- cies composition, and changes in soil water and nutrient concentrations in the soil profile. Results show that (1) repeated flood irrigation had a positive effect on seedling recruitment of the two species, with vegetative recruitment via root tillers being more important than seed recruitment for both species. (2) Irrigation promoted the germination and establishment of herbaceous weed species, which in- creased species diversity as well as ground coverage. (3) Irrigation also increased soil water and soil nutrient concentrations in the upper soil layer and changed the soil nutrients in the vertical profile. Available N, P, K and the total P and K increased in the soil profile. Our study demonstrates that naturally occurring flood irrigation has significant ecological benefits and plays an important role in promoting the renewal of desert vegetation and a short-term increase of soil nutrients. Our study also highlights the potential negative consequences for vegetation composition and rejuvenation if naturally occurring floods in the study area are diminished by either the effects of climate change or human management.
基金supported by the National Basic Research Program of China(2009CB825101)the Specialized Research Fund for the Doctoral Program of Higher Education of China(20110008110035)
文摘This paper focused on the water relations of two halophytes differing in photosynthetic pathway, phe- notype, and life cycle： Karelinia caspica （Pall.） Less. （C3, deep-rooted perennial Asteraceae grass） and Atriplex tatarica L. （C4, shallow-rooted annual Chenopodiaceae grass）. Gas exchange, leaf water potential, and growth characteristics were investigated in two growing seasons in an arid area of Xinjiang to explore the physiological adaptability of the two halophytes. Both K. caspica and A. tatarica showed midday depression of transpiration, in- dicating that they were strong xerophytes and weak midday depression types. The roots of A. tatarica were con- centrated mainly in the 0-60 cm soil layer, and the leaf water potential （~L） increased sharply in the 0-20 cm layer due to high soil water content, suggesting that the upper soil was the main water source. On the other hand, K. caspica had a rooting depth of about 1.5 m and a larger root/shoot ratio, which confirmed that this species uptakes water mainly from deeper soil layer. Although A. tatarica had lower transpiration water consumption, higher water use efficiency （WUE）, and less water demand at the same leaf water potential, it showed larger water stress impact than K. caspica, indicating that the growth of A. tatarica was restricted more than that of K. caspica when there was no rainfall recharge. As a shallow-rooted C4 species, A. tatarica displayed lower stomatal conductance, which could to some extent reduce transpiration water loss and maintain leaf water potential steadily. In contrast, the deep-rooted C3 species K. caspica had a larger root/shoot ratio that was in favor of exploiting groundwater. We concluded that C3 species （K. caspica） tapes water and C4 species （A. tatarica） reduces water loss to survive in the arid and saline conditions. The results provided a case for the phenotype theory of Schwinning and Ehleringer on halophytic plants.
文摘盐穗木是一种理想的耐盐模式植物,本文利用生物信息学方法分析盐穗木在盐胁迫下差异表达基因的转录组,为盐穗木耐盐机理及耐盐关键基因的储备提供理论依据。基于盐穗木在盐胁迫(600 mM NaCl)下差异表达的转录组数据,以代谢通路中基因表达数量最多的7条通路和与胁迫刺激响应相关的共8条通路为主要研究内容,筛选出上调和下调表达差异显著的unigene,将其与NCBI数据库中所有物种相关基因进行Blastx比对,筛选出通路中上调和下调差异表达最显著的unigene,同时对差异表达活跃的unigene进行分类汇总。共得到23组差异表达活跃的基因类群,分别是乙烯响应因子、WRKY转录因子、Myb转录因子、bZIP转录因子、葡聚糖酶、6-磷酸脱氢酶、醛脱氢酶、柠檬酸合成酶、蛋白激酶等,推测这些类群的基因在盐穗木耐盐机制中发挥重要作用。
