| Abstract: | The epigeal portion of the gynophore has a typical herbaceous stem structure. It is found that the young gynophore is composed of epidermis, cortex and vascular cylinder. Periderm, lenticelle and secondary vascular tissue in the gynophore are produced due to its secondary growth. The region of cell division in the gynophore is located at 0.9–1.9 mm from the peg apex, and that of cell elongation at 2.0–4.5 mm. These two regions are found to overlap at 2.0–2.5 mm from peg apex. The results of the experiment exhibit clearly that the growing region of the gynophore grows toward the gravitional direction of the earth when the gynophore is placed either in a vertical position or in a horizontal position, thus the elongating gynophore shows a positive geotropic response. The distributed position of starch grains in the pith parenchyma sedimented to the side of cell wall near the earth surface. All this shows that there is a close relation between the positive geotropic growth of the peanut gynophore and the distribution of starch statoliths in the pith of the gynophore under the influence of gravity. |
