Turned off the weather channel again today when they started claiming that increased CO2 would supposedly make our wheat less nutritious. Seems like simple Climate Alarmism From what I read on Google Scholar, that claim depends on whether or not other nutrients are deficient or not. It appears that plants need more nitrogen as CO2 is raised, because plant productivity increases Nitrogen nutrition of C3 plants at elevated atmospheric CO2 concentrations The atmospheric CO2 −1 to more than 350 μl l−1 in 1993. The current rate of rise is such that concentrations of 420 μl l−1 are expected in the next 20 years. For C3plants, higher CO2 levels favour the photosynthetic carbon reduction cycle over the photorespiratory cycle, resulting in higher rates of carbohydrate production and plant productivity. The change in balance between the two photosynthetic cycles appears to alter nitrogen and carbon metabolism in the leaf, possibly causing decreases in nitrogen concentrations in the leaf. This may result from increases in the concentration of storage carbohydrates of high molecular weight (soluble or insoluble) and/or changes in distribution of protein or other nitrogen containing compounds. Uptake of nitrogen may also be reduced at high CO2 due to lower transpiration rates. Decreases in foliar nitrogen levels have important implications for production of crops such as wheat, because fertilizer management is often based on leaf chemical analysis, using standards estimated when the CO2 levels were considerably lower. These standards will need to be re-evaluated as the CO2concentration continues to rise. Lower levels of leaf nitrogen will also have implications for the quality of wheat grain produced, because it is likely that less nitrogen would be retranslocated during grain filling. onlinelibrary.wiley/doi/10.1111/j.1399-3054.1993.tb05215.x/abstract
Posted on: Wed, 16 Apr 2014 14:51:07 +0000
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