Root-hair structure and development in the seagrass Halophila ovalis (R. Br.) Hook. F

Abstract

The seagrass Halophila ovalis normally produces one mature root, covered with a permanent mat of root hairs, per node. In this study, the development of the root hairs increased the effective root surface absorptive area by 215%. Of the root surface examined, 39% was devoted to root-hair production. Epidermal cells that produced root hairs contained more cytoplasm, endoplasmic reticulum and Golgi bodies than did adjacent hairless cells. In addition to appearing to be more metabolically active, root-hair-producing cells had a greater number of plasmodesmatal connections with the underlying outer cortical cells than did adjacent cells that did not produce root hairs. This would suggest that cells that produce root hairs play a more active role in nutrient uptake and exchange than do other cortical cells.