Interactive Effects of Elevated Carbon Dioxide, Soil Moisture and Nitrogen on the Growth and Development of Winter Wheat
|School||Chinese Academy of Agricultural Sciences|
|Keywords||FACE winter wheat water treatment nitrogen treatment yield|
Wheat is the main food crop in China and the world. With the elevated carbon dioxide, theprecipitation change and the differences of the nitrogen application will directly affect the crop’s growthand development and crop yields. Therefore, the research about the interactive effects of the elevatedcarbon dioxide, water and nitrogen application is very important for food safety in future. Theexperiment was conducted to investigate the effect of two atmospheric CO2concentrations: elevatedcarbon dioxide(550μmol·mol-1) and ambient carbon dioxide(400μmol·mol-1), two levels of soilmoisture: high moisture （75%soil field capacity）and low moisture （55%soil field capacity） and twolevels of nitrogen application: high nitrogen application(0.16g·kg-1) and low nitrogen application(0g·kg-1) on the morphological parameters, the photosynthesis parameters, fluorescence parameters, theaboveground biomass, yield per plant and yield components of winter wheat（ZM175, the majorvarieties of wheat in Beijing） with pot-culturing method in FACE system at Changping, Beijing.Conclusions are listed as follows:（1） The effects of elevated CO2on the growth and the development of winter wheatThe elevated atmospheric CO2enhanced significantly the aboveground biomass and yield per plantby15.0%and14.8%.The elevated atmospheric CO2significantly increased net photosynthetic rate by13.7%and wateruse efficiency by54.7%. The increased net photosynthetic rate and the decreased transpiration ratetogether leaded to the increasement of water use efficiency under the elevated atmospheric CO2.Yield, ETR and qP decreased significantly under the elevated atmospheric CO2. This reflected thatit maight occur photosynthetic acclimation under the elevated atmospheric CO2.（2） The interactive effects of elevated CO2and soil moisture on the growth and the development ofwinter wheatCompared with the high moisture environment, low moisture condition significantly enhanced theaboveground biomass by19.2%and increased the yield per plant by12.8%under elevated atmosphericCO2. Thus, the elevated CO2partly reduced the deleterious effects of water stress on the winter wheat.Compared with the high moisture environment, low moisture condition significantly decreasedstomatal conductance by2.3%and transpiration rate by5%, but significantly increased netphotosynthetic rate by5.4%and water use efficiency by11.4%under elevated atmospheric CO2andsufficient nitrogen treatment. Thus, the elevated atmospheric CO2partly reduce the deleterious effects ofwater stress on the photosynthesis.（3） The interactive effects of elevated CO2and nitrogen on the growth and the development ofwinter wheatThe elevated atmospheric CO2remarkably enhanced the aboveground biomass by7.9%at theripening stage and increased the yield per plant by12.8%in high nitrogen condition than in lownitrogen environment. Therefore, nitrogen application had a more positively effect on the CO2 fertilization.The elevated atmospheric CO2remarkably increased F0by2.5%and significantly decreased Fv/F0and qP by4.1%and4.5%in high nitrogen condition than in low nitrogen environment. This showedthat with nitrogen application it would reduce the degree of damaged PSⅡreaction center and enhancedthe potential activity of PSⅡand increased the opening ratio of PSⅡreaction center under the elevatedatmospheric CO2. It alleviated the degree of photosynthetic acclimation under the elevated atmosphereCO2.（4） The interactive effects of elevated CO2，soil moisture and nitrogen on the growth and thedevelopment of winter wheatCO2enrichment increased the aboveground biomass and the yield per plant by3.7%and4.8%inhigh nitrogen and high water condition than in low nitrogen and low water environment. This showedthat nitrogen application and high water had a more positively effect on the CO2fertilization.CO2enrichment increased Fv, Yield, ETR and qP by5.0%,7.8%,7.8%and6.2%in high nitrogenand high water condition than in low nitrogen and low water environment. This showed that nitrogenapplication and high water enhanced the reducing power of primary electron receptor, actualphotochemical efficiency of PSⅡ, resulted in more photosynthetic electron transported tophotochemical progress and alleviated the degree of photosynthetic acclimation under the elevatedatmosphere CO2.