Putative Causes and Consequences of Recycling CO2 via Crassulacean Acid Metabolism

摘要: The fate of respiratory CO2 released simultaneously with the absorption atmospheric at night during crassulacean acid metabolism (CAM) is inevitable; both sources will contribute to nocturnal accumulation malate. As a result, determinations stoichiometric relationships between amount malate accumulated overnight and net absorbed from external atmosphere should yield values greater than unity. Surprisingly, this seldom case. Studies numerous CAM species under optimal conditions report ratios (hereafter referred as “malate/CO2”) consistently near one (Medina Delgado 1976; Nobel Hartsock 1978, 1983; Eickmeier 1979; et al. 1984; Winter 1986; Virzo De Santo 1987). Apparently, either rate respiration too low substantially pool malate, or experimental variability in measurements assimilation might obscure small differences these measures CAM.