CO_2浓度升高与水分互作对冬小麦生长发育的影响

Interactive Effects of Elevated Carbon Dioxide and Water on the Growth and Development of Winter Wheat

利用开放式大气CO2浓度富集系统(FACE)试验平台,研究了CO2肥效作用与水分条件互作关系,以期明确水分条件对CO2肥效的影响。试验设高CO2浓度(550μmol·mol-1)和正常大气CO2浓度(400μmol·mol-1)、高水分条件(75%田间持水量)和低水分条件(55%田间持水量)的交互处理,观测冬小麦叶片光合参数、蒸腾作用、干物质积累以及产量构成的变化。结果表明,CO2浓度升高显著降低了冬小麦气孔导度和蒸腾速率,但同时又提高了叶片净光合速率、水分利用效率和植株生物学产量,对冬小麦的生长发育和产量形成具有明显的促进作用。在低水分条件下,高浓度CO2对气孔导度和蒸腾速率降幅高于高水分条件处理,对净光合速率、水分利用效率、干物质积累以及植株产量的提高幅度也强于高水分条件处理。研究结果表明CO2浓度升高可能在一定程度上缓解水分不足对冬小麦的胁迫程度,CO2肥效作用在低水分条件下表现更明显。

In order to find out the influence of water conditions on the CO2 fertilization, free Air CO2 Enrichment （FACE） system was conducted to research the interaction of the CO2 fertilization and water conditions. Winter wheat was treated with two atmospheric CO2 concentrations： elevated carbon dioxide（550μmol. mol^-1） and ambient carbon dioxide（400μmol.mol^-1） and two levels of soil moisture： high moisture （75% soil field capacity）and low moisture （55% soil field capacity） to observe the photosynthesis parameter, transpiration, dry matter accumulation and yield components. The results showed that elevated atmospheric CO2 decreased significantly stomatal conductance and transpiration rate, but significantly increased net photosynthetic rate, water use efficiency, yield per plant. The elevated CO2 dramatically benefited for the growth and development of winter wheat and its yield formation. Compared with the high moisture environment, low moisture condition decreased stomatal conductance and transpiration rate, increased net photosynthetic rate, water use efficiency, dry matter accumulation and yield component under elevated CO2. Thus, the elevated CO2 partly reduce the deleterious effects of water stress on the winter wheat. It is much more beneficial for the CO2 fertilization under low moisture environment.