Is guava phenolic metabolism influenced by elevated atmospheric CO sub(2)?

Seedlings of Psidium guajava cv. Pedro Sato were distributed into four open-top chambers: two with ambient CO sub(2) (390 ppm) and two with elevated CO sub(2) (780 ppm). Monthly, five individuals of each chamber were collected, separated into root, stem and leaves and immediately frozen in liquid nitrogen. Chemical parameters were analyzed to investigate how guava invests the surplus carbon. For all classes of phenolic compounds analyzed only tannins showed significant increase in plants at elevated CO sub(2) after 90 days. There was no significant difference in dry biomass, but the leaves showed high accumulation of starch under elevated CO sub(2). Results suggest that elevated CO sub(2) seems to be favorable to seedlings of P. guajava, due to accumulation of starch and tannins, the latter being an important anti-herbivore substance.