Photosynthetic Reactions in the Marine Alga Codium vermilara

Chloroplasts were isolated from the marine alga Codium vermilara (Siphonales). The isolated chloroplasts were active in CO(2) fixation in the light at a rate comparable to the rates obtained by fragments of thalli. Maximal rates of CO(2) fixation by isolated chloroplasts from Codium were obtained in the presence of salt or sorbitol isoosmotic with sea water. The conditions of isolation of Codium chloroplasts are much less stringent than those required for active chloroplasts from higher plants. The isolated chloroplasts comprise a homogeneous population of the intact "class I" type, as based on microscopic observations and on their inability to reduce ferricyanide unless osmotically shocked. The intact chloroplasts are able to reduce p-benzoquinone at a high rate.