Resumo

PIMIENTA-BARRIOS, Eulogio; ZANUDO-HERNANDEZ, Julia  e  GALLEGOS-RODRIGUEZ, Agustín. Seasonal variation in daily net CO₂ assimilation for Quercus magnolifolia Née. Agrociencia [online]. 2011, vol.45, n.6, pp.711-718. ISSN 2521-9766.

The process of photosynthesis has been little studied in oaks (Quercus) of México, habitats considered the center of origin and diversification of oak species. The seasonal measurements of photosynthesis in forest species are important to identify abiotic environmental factors that are important in regulating this process. The effect of seasonal variation on irradiance, air temperature, relative air humidity and soil water content in daily net CO₂ uptake for Quercus magnolifolia Née, was studied during 2004. The experimental design was a randomized complete blocks design; treatments were three measurement dates (June 11, September 3 and October 22) of photosynthesis from June to October 2004. The highest value of daily net CO₂ uptake was recorded on June 11 at the end of spring and beginning of rains, and not in the summer when the environmental conditions are favorable for photosynthesis in plants with C₃ photosynthetic metabolism as Q. magnolifolia. The highest total daily net CO₂ uptake coincided with the highest values of both irradiance and temperature and when rains began.

Palavras-chave : photosynthesis; soil moisture; irradiance; oaks.

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