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sur le développement des zones arides et semi-arides

Titre : Seasonal variation of net CO2 uptake for cactus pear (opuntia ficus-indica) and pitayo (stenocereus queretaroensis) in a semiarid environment

Auteur : Yépez González Enrico Arturo

Etablissement de soutenance : Universidad de Guadalajara (UDG)

Grade : Licenciatura en Biología 1999

Résumé
The objective of this work was to evaluate the effects of seasonal variation in temperature, irradiation and soil moisture content on the photosynthetic rates of Opuntia ficus-indica and Stenocereus queretaroensis. The lowest values of positive daily net CO, uptake were recorded during the summer rainy season and the highest values during autumn and winter. These highest values were likely the result of a prolonged period of C02 assimilation caused by decreased cloudiness, and high rates o[ nocturnal co2 assimilation dueto moderate day/night air temperatures. In spring, when drought was exacerbated, daily net CO, uptake was negative for both O. ficus-indica and S. queretaroensis . Stem photosynthesis allowed both O. ficus-indica and S. queretaroensis to obtain carbon during the fall and winter, when the soil water was lowest.

Mots clés : Opuntia ; Stenocereus ; air temperature ; drought ; gas exchange ; phenology ; photosynthetic photon flux ; stress

Présentation

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