TITLE:
Elevated CO2 Levels Affect Phytochemicals and Nutritional Quality of Food Crops
AUTHORS:
C. B. Rajashekar
KEYWORDS:
Elevated CO2, Food Crops, Nutritional Quality, Phytochemicals, Secondary Metabolites
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.9 No.2,
January
24,
2018
ABSTRACT: Rising atmospheric CO2 levels pose many
challenges to global climate, thus to all forms of life including plants. The impact of
elevated CO2 on plant growth and development and the nutritional
quality in relation to major nutrients in many crops has been explored
extensively. However, information on the elevated CO2 effects on the
health-promoting phytochemicals in food crops is rather limited. Major
nutrients in food crops including protein, phosphorus, potassium, calcium,
iron, zinc and other micronutrients in many food crops are known to be
suppressed at elevated CO2 levels. Elevated CO2 increases
carbohydrate accumulation but decreases nitrogen accumulation in plants thus
affecting their C-N ratio. A number of studies show that high C-N ratio and
nitrogen limiting conditions in plants can result in the accumulation of
carbon-based secondary metabolites, many of which are health-promoting
phytochemicals and allelochemicals involved in plants’ defense against
pathogens and herbivory. Although the results from these studies are variable, it can be concluded
that while elevated CO2 is known to suppress the content of major
nutrients, it may actually have a favorable impact on the accumulation of
carbon-based phytochemicals in food crops.