PHOTOSYNTHESIS BY PROTOPLASM EXTRUDED FROM CHARA AND NITELLA

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Abstract
Photosynthesis as measured by NaHC14O3 fixation has been obtained with cell-free protoplasm extruded from Chara and Nitella at the rate 12 to 15% of that of the whole cells. The rate of photosynthesis by cut cells of Chara or Nitella without the vacuolar sap has been obtained at a rate comparable to that of the whole cells. Thus neither whole cells nor vacuolar sap are necessary for photo -synthesis . Various factors, both physical and chemical, were checked for their effect on the fixation rate for both cut cells and cell-free protoplasm. Detail chromatographic analysis of the products formed by w ole cells, cut cells, or extruded protoplasm in the light or dark was made. Both the protoplasm and the cut cells reduced CO2 in the light to sucrose and hexose phosphates. In contrast, dark controls fixed the C14 into products associated with plant respiration. An important difference in the products from the cell-free protoplasm was the absence of C14-labelled pentoses or sedoheptulose which were formed, however, by the whole or cut cells. This suggests that the most sensitive site affected by disruption of the cells may be the steps involved in regeneration of the "C-2 acceptor" for CO2 fixation in photosynthesis.