Dark Fixation of CO₂ by Tobacco Leaves.

Abstract

The ability of non-succulent plants to fix C02 in the absence of light has been previously demonstrated by several investigators (2,5,11,17,21). However, the succulents have received the greatest attention because of the large amounts of C02 incorporated into organic acids in the dark.Although these earlier reports strongly suggested that dark fixation of C02 is an

Photosynthesis in C4 Plant Tissue Cultures

“…Roughly 50% of the 14CO2 fixed in the dark by most plant tissues is located in malate (10,15,21). While Portulaca leaves also show this pattern of dark fixation, cultured tissue has only 20% located in malate (Table I), with an equal amount in aspartate.…”

Formation of sucrose from malate in germinating castor beans. I. Conversion of malate to phosphoenol-pyruvate

“…It has been established that the enzymes phosphoenol-pyruvate (PEP) carboxylase (reaction i), PEP carboxykinase (reaction ii), and malic enzyme (reaction iii) are widely distributed in plants (3,9,16) and are present in tissues capable of an active dark CO, fixation (8,17).…”

“…The question of which of these enzymes is operative during acid accumulation is unresolved (9,17) (11). The slices were placed in KHC1403 and 0.05 M KH2PO4 buffer pH 7.2.…”

Acid Metabolism in Atriplex II. Oxalate Synthesis During Acid Metabolism in the Dark

“…,B.Carb<?xylation of phosphoenol pyruvate, the principal dark carboxylation reaction in A. spongiosa leaves, provides the basis of a non·crassulacean acid metabolism common in plant tissues ( Jackson and Coleman 1959;Kunitake, Stitt, and Saltman 1959). Oxalate is not an early product of the carboxylation reactions but, as malonate sensitivity suggests, is synthesized from intermediates of subsequent TCA cycle metabolism.…”