| This is the first study of photosynthesis in polyploid C;In autotetraploid Pennisetum americanum (Tift 239DB), bundle sheath cell volume doubled, and mesophyll cell volume increased 45% compared with the diploid. There were exactly half as many cells per unit area in the tetraploid. Chlorophyll, DNA, and soluble protein, number of chloroplasts, and the photosynthetic rate all doubled per cell in the tetraploid, but were constant per unit leaf area at both ploidy levels.;In Panicum virgatum L., DNA, chlorophyll, and soluble protein, and the photosynthetic rate per cell all doubled in the octaploid, but cell volumes increased only about 20% over the tetraploid. Number of cells per unit area decreased about 30%, which, combined with a doubling of photosynthetic capacity per cell, resulted in a 40% higher photosynthetic rate per unit leaf area in the octaploid. Changes in chlorophyll, DNA, and soluble protein, and activities of photosynthetic enzymes per unit leaf area correspond to changes in the photosynthetic rate.;In the C;In these polyploid plants, photosynthetic rates per cell are determined largely by gene dosage per cell. Photosynthetic rates per unit leaf area are determined by the number of cells per unit leaf area, which is a product of cell volume and cell packing in the leaf. |
