Interactive response of photosynthetic characteristics in Haloxylon ammodendron and Hedysarum scoparium exposed to soil water and air vapor pressure deficits.
Interactive response of photosynthetic characteristics in Haloxylon ammodendron and Hedysarum scoparium exposed to soil water and air vapor pressure deficits.
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DOI：
10.1016/j.jes.2015.03.012
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发表时间：
2015-08
影响因子：
6.9
通讯作者：
Chunmei Gong;Jiajia Wang;Congxia Hu;Junhui Wang;P. Ning;J. Bai
中科院分区：
文献类型：
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作者：
Chunmei Gong;Jiajia Wang;Congxia Hu;Junhui Wang;P. Ning;J. Bai
C4植物比C3植物具有更好的耐旱性。而花棒（Hedysarum scoparium）是我国西北荒漠地区的优势种，具有较强的耐旱性。本研究以梭梭为对照，探讨了干旱胁迫与不同叶片-空气水汽压亏缺的交互作用。感兴趣的变量包括气体交换，关键C4光合酶的活性水平，和细胞解剖。在这两个物种中，气体交换参数更敏感的高蒸汽压赤字比强水分胁迫，和净CO2同化率（An）的提高，蒸汽压赤字增加。气孔导度（gs）与气孔导度（Anc）的关系密切，说明这两种植物具有相似的响应机制. INH.在梭梭中，磷酸烯醇式丙酮酸羧化酶（PEPC）和烟酰胺腺嘌呤二核苷酸磷酸苹果酸酶（NADP-ME）活性较高，而inH.烟酰胺腺嘌呤二核苷酸苹果酸酶（NAD-ME）活性水平较高。同时，H. scoparium利用了适应性的结构特征，包括较大的相对导管面积和较短的脉到气孔的距离，这有利于水分的运动。这些结果表明，一些C4生化途径存在于H。scoparium应对环境挑战。
C4plants possess better drought tolerance than C3plants. However,Hedysarum scoparium, a C3species, is dominant and widely distributed in the desert areas of northwestern China due to its strong drought tolerance. This study compared it withHaloxylon ammodendron, a C4species, regarding the interactive effects of drought stress and different leaf–air vapor pressure deficits. Variables of interest included gas exchange, the activity levels of key C4photosynthetic enzymes, and cellular anatomy. In both species, gas exchange parameters were more sensitive to high vapor pressure deficit than to strong water stress, and the net CO2assimilation rate (An) was enhanced as vapor pressure deficits increased. A close relationship betweenAnand stomatal conductance (gs) suggested that the species shared a similar response mechanism. InH. ammodendron, the activity levels of key C4enzymes were higher, including those of phosphoenolpyruvate carboxylase (PEPC) and nicotinamide adenine dinucleotide phosphate-malate enzyme (NADP-ME), whereas inH. scoparium, the activity level of nicotinamide adenine dinucleotide-malate enzyme (NAD-ME) was higher. Meanwhile,H. scopariumutilized adaptive structural features, including a larger relative vessel area and a shorter distance from vein to stomata, which facilitated the movement of water. These findings implied that some C4biochemical pathways were present inH. scopariumto respond to environmental challenges.