Prasad P V Vara, Vu Joseph C V, Boote Kenneth J, Allen L Hartwell
Agronomy Department, 2004 Throckmorton Hall, Kansas State University, Manhattan, KS 66506, USA.
United States Department of Agriculture - Agricultural Research Service, Center for Medical, Agricultural and Veterinary Entomology, Chemistry Research Unit, Gainesville, FL 32608, USA.
Funct Plant Biol. 2009 Sep;36(9):761-769. doi: 10.1071/FP09043.
Rising atmospheric carbon dioxide (CO) concentration and temperature will influence photosynthesis, growth and yield of agronomic crops. To investigate effects of elevated CO and high temperature on leaf gas exchanges, activities of Rubisco and phosphoenolpyruvate carboxylase (PEPC) and growth of grain sorghum (Sorghum bicolor L. Moench), plants were grown in controlled environments at day-time maximum/night-time minimum temperatures of 30/20°C or 36/26°C at ambient (350 µmol mol) or elevated (700 µmol mol) CO. Gas-exchange rates, activities of Rubisco and PEPC and growth parameters (leaf, stem and total dry weights) were determined at different stages of leaf development. Between 6 and 25 days after leaf tip emergence, leaf carbon exchange rate (CER) of elevated CO plants was greater at 30/20°C and 36/26°C than that of ambient CO plants at the same temperatures. The positive response of CER to elevated CO was greater in young leaves than in old leaves. In young leaves, elevated CO enhanced Rubisco activity at 30/20°C and 36/26°C, whereas PEPC activity was not affected by elevated CO at 30/20°C but was marginally enhanced at 36/26°C. At 30/20°C, growth parameters were not affected by elevated CO until 50 days after sowing (DAS); at 36/26°C, they were progressively enhanced by elevated CO to as high as 49 to 62% by 50 DAS. Leaf CER and Rubisco activity were enhanced by elevated CO at early stages of leaf ontogeny for the C grain sorghum. Such enhancement should have a significant role in dry matter production under elevated CO.
大气中二氧化碳（CO₂）浓度上升和气温升高会影响农作物的光合作用、生长和产量。为了研究二氧化碳浓度升高和高温对叶片气体交换、核酮糖-1,5-二磷酸羧化酶（Rubisco）和磷酸烯醇式丙酮酸羧化酶（PEPC）活性以及高粱（Sorghum bicolor L. Moench）生长的影响，将植株种植在可控环境中，白天最高/夜间最低温度分别为30/20°C或36/26°C，二氧化碳浓度为环境浓度（350 µmol/mol）或升高浓度（700 µmol/mol）。在叶片发育的不同阶段测定气体交换速率、Rubisco和PEPC活性以及生长参数（叶片、茎和总干重）。在叶尖出现后的6至25天内，在30/20°C和36/26°C条件下，二氧化碳浓度升高的植株的叶片碳交换率（CER）高于相同温度下二氧化碳浓度为环境浓度的植株。CER对二氧化碳浓度升高的积极响应在幼叶中比在老叶中更大。在幼叶中，二氧化碳浓度升高在30/20°C和36/26°C时增强了Rubisco活性，而在30/20°C时PEPC活性不受二氧化碳浓度升高的影响，但在36/26°C时略有增强。在30/20°C时，直到播种后50天（DAS），生长参数不受二氧化碳浓度升高的影响；在36/26°C时，到50 DAS时，它们因二氧化碳浓度升高而逐渐增强，增幅高达49%至62%。对于C₄高粱，在叶片发育早期，二氧化碳浓度升高增强了叶片CER和Rubisco活性。这种增强在二氧化碳浓度升高条件下的干物质生产中应具有重要作用。
