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
【目的】研究盐穗木乙醛脱氢酶7B4基因(HcALDH7B4)在原核细胞中的耐盐抗旱功能,为耐盐抗旱育种提供候选基因。【方法】利用qRT-PCR检测高盐和干旱胁迫下HcALDH7B4基因的表达水平;利用原核表达重组大肠杆菌(pET-28a-HcALDH7B4)在盐旱胁...【目的】研究盐穗木乙醛脱氢酶7B4基因(HcALDH7B4)在原核细胞中的耐盐抗旱功能,为耐盐抗旱育种提供候选基因。【方法】利用qRT-PCR检测高盐和干旱胁迫下HcALDH7B4基因的表达水平;利用原核表达重组大肠杆菌(pET-28a-HcALDH7B4)在盐旱胁迫下的菌落大小和生长活力分析其盐旱抗性。【结果】在600 mM NaCl处理和自然干旱条件下,盐穗木同化枝中HcALDH7B4被显著诱导。相较对照菌株(pET-28a),原核表达的重组大肠杆菌在500 mM NaCl、500 mM KCl和500 mM、800 mM Mannitol胁迫下表现出更好的生长活力。【结论】盐穗木HcALDH7B4是一个胁迫应答基因,可以提高重组菌盐旱胁迫的耐受性。展开更多
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【目的】研究盐穗木乙醛脱氢酶7B4基因(HcALDH7B4)在原核细胞中的耐盐抗旱功能,为耐盐抗旱育种提供候选基因。【方法】利用qRT-PCR检测高盐和干旱胁迫下HcALDH7B4基因的表达水平;利用原核表达重组大肠杆菌(pET-28a-HcALDH7B4)在盐旱胁迫下的菌落大小和生长活力分析其盐旱抗性。【结果】在600 mM NaCl处理和自然干旱条件下,盐穗木同化枝中HcALDH7B4被显著诱导。相较对照菌株(pET-28a),原核表达的重组大肠杆菌在500 mM NaCl、500 mM KCl和500 mM、800 mM Mannitol胁迫下表现出更好的生长活力。【结论】盐穗木HcALDH7B4是一个胁迫应答基因,可以提高重组菌盐旱胁迫的耐受性。
