Growth of Photoheterotrophic Cells of Peanut (Arachis hypogaea L.) in Still Nutrient Medium

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Abstract
Cell suspension cultures were established from the callus proliferation of leaf explants of 10- to 12-day-old seedlings of the peanut (Arachis hypogaea L. var. TMV-3). The cells could be cultivated in both agitated and still media, the latter promoting more of chlorophyll (Chl) synthesis. High Chl content (210-240 micrograms Chl per gram fresh weight), yield of free and pipetable cells, presence of all the pigments in the same ratio as that of the leaf tissue, and high rates of O2 evolution (140-170 micromoles O2 per milligram Chl per hour) were some of the desirable features of the still-grown cell cultures. However, considerable variations with regard to the above characters were observed between the cell cultures of different varieties of the peanut. O2 evolution by the cultured cells was dependent on exogenous supply of HCO3−. A well-developed photosynthetic apparatus as evidenced from photosystem I and photosystem II activities of the isolated chloroplasts and variable fluorescence measurements with the cell cultures was further documented by electron microscopic evidence of distinct granal stackings in chloroplasts and sodium dodecyl sulfate-polyacrylamide gel separation of thylakoid membranes into P700 Chl a protein complex and light-harvesting Chl a/b complex. Evidence is presented for the relative increase in the Chl associated with P700 Chl a protein complex in contrast to the light-harvesting Chl a/b complex in the cultured cells as compared to intact leaf.