Comparative Estimation of Cyclic and Noncyclic Photophosphorylation in N₂ by Ankistrodesmus Braunii In Vivo

Abstract

Noncyclic photophosphoryl at ion has long been studied in chloroplasts and it has been generally accepted that it is closely coupled to photosynthetic electron transport in vivo. Cyclic photophosphorylation has been demonstrated so far in vivo especially under conditions under which electron acceptors are not or are scarcely available. The methods used range from light dependent ion uptake (JESCHKE 1967, RAVEN 1970, VAN RENSEN 1969), photoassimilat ion of acetate (WIESSNER 1963), and glucose uptake (KANDLER & TANNER 1966) to measurements of ATP pool changes in the cells (FORTI & PARISI 1963, URBACH & KAISER 1972). Among these reactions, more or less linked to cyclic photophosphorylat ion in nitrogen atmosphere,³²P-incorporation into organic phosphates was investigated (URBACH & SIMONIS 1964, 1967) and provided qualitative proof for its existence.