Bioresource and Agricultural Engineering Commons^™

Light, Chlorophyll, Carboxylase Activity And Co2 Fixation At Various Depths In The Chlorenchyma Of Opuntia Ficus-Indica (L.) Miller Under Current And Elevated Co2, Park S. Nobel, Muyi Cui, Alvaro A. Israel

US Department of Energy Publications

Mature cladodes of Opuntia ficus-indica (L.) Miller have a thick chlorenchyma (about 4 mm) with a relatively high chlorophyll content (0-65 g m^-2), suggesting that light may be greatly attenuated and hence CO₂ fixation negligible in the inner part of this tissue. Indeed, blue light (400-470 nm) and red light (670-685 nm) were 99% attenuated in the outer 2 mm of the chlorenchyma when the cladodes developed under both current and elevated CO₂ concentrations. Nevertheless, the nocturnal acidity increase and ¹⁴C accumulation following a brief exposure to ¹⁴CO₂ at night decreased only 22 …