Ecophysiological studies inHesperaloe funifera(Agavaceae): a potential new CAM crop. Seasonal patterns of photosynthesis

The objective of this study was to evaluate the effect of seasonal variation in temperature and irradiation on photosynthesis rates, proportion of nocturnal CO2uptake, and water-use efficiency (WUE) inHesperaloe funifera(Agavaceae), and to discuss what these seasonal patterns reveal about the nature of the interactions among environmental factors as they affect CO2uptake. CO2uptake showed the highest 24 h integrated values in fall and spring and the lowest in winter and summer. Temperature and light do not appear to interact in a simple multiplicative manner in their relationship to photosynthesis. A conceptual model describing the seasonal pattern of photosynthetic capacity inHesperaloeis presented. Moderately high daily integrated CO2uptake rates, a long growing season, and high WUE throughout the year have agronomic significance forHesperaloeas a potential new crop for arid lands.