An experiment was made to analyze the influence of CO2concentration and atmospheric rising to potato growth in the semiarid region of Loess Plateau. During the experiment, the morphology structure, stem tuber formation, water content physiology, ecology and carbon exchange were observed. The collaborative influence of elevated CO2concentration and atmospheric warming on potato photosynthetic physiology ecology, as well as the characteristic of leaf's photoresponse process and yield formation in the semi-arid region of Loess Plateau was studied based on a parallel observation on meteorological element. The result showed: the precipitation in the experiment region decreased in 1958—2016, with a decreasing rate of -12.17 mm·(10 a)-1; the air temperature rose significantly in recent 59 a, the climatic tendency rate of linear regression was 0.42 ℃·(10 a)-1; the temperature had kept rising since 1980s, and the rising was especially significant after 2000. When potato was treated by warming and CO2concentration elevating during the growing stage, it could be found that the net photosynthesis rate of potato leaves was improved and higher than that of the control group and group of potatoes treated in other ways; during the late growing stage, the net photosynthesis rate of leaves treated by warming and CO2concentration elevating decreased more quickly. As the ambient CO2concentration increased, the leaf stomatal conductance gradually decreased, and the stomatal conductance of leaves treated by warming and CO2concentration elevating during the growing stage was lower than control group. The leaf transpiration rate increased with warming, which was higher compared to control group and group treated in other ways, in the early growing stage, meanwhile, the transpiration rate became lower in the late growing stage compared to control group. The water use efficiency of leaves treated by warming and CO2 concentration elevating was distinctly improved and higher than control group and group treated only by warming. Under the background of warming and CO2concentration elevating, the threshold of photosynthetic active radiation flux density can be increased when the assimilation of photosynthesis is equal to the respiration consumption during the photosynthesis process of potato leaves. Photosynthesis ability as well as maximum synthesis ability increase under weak light conditions, while the threshold of photosynthetic active radiation flux density increase when assimilation of photosynthesis reached maximum value. The coordinating influence of warming and CO2concentration elevating to some extent can relieve the influence of dark respiration rate caused by warming. The actual yield of potatoes treated by warming and CO2concentration elevating was distinctly higher than control group and group treated only by warming. The yield of potatoes treated only by warming was relatively lower, which indicated that in the semi-arid region of Loess Plateau, warming went against the expansion of potato stem tubers. Warming during the stem tuber expansion stage would delay the potato tuber growth and deform the tubers. Therefore, warming synchronized with CO2 concentration elevating will improve the net photosynthesis rate and water use efficiency of potato leaves, promote the dry matter accumulation and increase the yield.%基于黄土高原典型半干旱区 CO2浓度升高与大气增温对马铃薯生长发育的影响试验,观测马铃薯形态结构、块茎形成、水分生理生态和碳交换的变化过程,研究 CO2浓度升高与大气增温对黄土高原半干旱区马铃薯光合生理生态与叶片光响应过程特征及产量形成的协同影响.结果表明,试验区1958—2016年降水量呈减少趋势,降水量倾向率为-12.17 mm·(10 a)-1;近59年,气温呈极显著上升趋势,气温线性回归气候倾向率为0.42 ℃·(10 a)-1;20世纪70年代后,气温持续上升,进入21世纪后升温尤为显著.对马铃薯生育期进行增温加CO2浓度升高复合处理,马铃薯叶片净光合速率提高且高于对照及其他处理;在生育后期,叶片净光合速率下降更为迅速.随着环境 CO2浓度升高,叶片气孔导度逐渐降低,气孔导度小于对照.叶片蒸腾速率随增温处理而升高,生育前期高于对照和其他处理,后期低于对照.经复合处理,叶片的水分利用效率明显提高,高于对照和单独增温处理.增温和 CO2浓度升高背景下,马铃薯叶片光合作用过程中光合同化作用与呼吸消耗相当时的光合有效辐射通量密度阈值提高,马铃薯叶片在弱光条件下的光合能力增加,最大光合能力也增加,最大同化作用时光合有效辐射通量密度阈值增高.增温和 CO2浓度升高协调影响,可在一定程度上缓解增温所造成的暗呼吸速率升高的影响.经复合处理,马铃薯实际产量明显高于对照和单独增温处理;单独增温处理产量偏低.在黄土高原半干旱区,气温增高不利于马铃薯块茎的膨大,高温会导致块茎膨大期薯块生长停滞,形成畸形薯块,因而,在增温的同时提高 CO2浓度,可以使马铃薯叶片净光合速率和水分利用效率提高,干物重积累增多,产量增加.
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