ECOPHYSIOLOGICAL STUDIES IN HESPERALOE-FUNIFERA (AGAVACEAE) - A POTENTIAL NEW CAM CROP - SEASONAL PATTERNS OF PHOTOSYNTHESIS

The objective of this study was to evaluate the effect of seasonal var iation in temperature and irradiation on photosynthesis rates, proport ion of nocturnal CO2 uptake, and water-use efficiency (WUE) in Hespera loe funifera (Agavaceae), and to discuss what these seasonal patterns reveal about the nature of the interactions among environmental factor s as they affect CO2 uptake. CO2 uptake showed the highest 24 h integr ated values in fall and spring and the lowest in winter and summer. Te mperature and light do not appear to interact in a simple multiplicati ve manner in their relationship to photosynthesis. A conceptual model describing the seasonal pattern of photosynthetic capacity in Hesperal oe is presented. Moderately high daily integrated CO2 uptake rates, a long growing season, and high WUE throughout the year have agronomic s ignificance for Hesperaloe as a potential new crop for arid lands. (C) 1996 Academic Press Limited