DR JEREMY BURGESS / SCIENCE PHOTO LIBRARY DR JEREMY BURGESS / SCIENCE PHOTO LIBRARY
A potbound plant of Chinese woad, Isatis indigotica, a member of the family Cruciferae. The roots of plants grow downwards due to geotropism. In pot-grown plants the vertical growth is eventually prevented as the roots reach the base of the container. The roots are constrained to grow horizontally, and eventually encircle the soil within the pot, forming a tangled mass. Good horticultural practice avoids this condition by re-potting the plant into a larger container before it develops. The picture shows a plant that has been growing in a 20cm plastic pot for 3 months. All the roots visible ( white ) are primary roots, with root hairs visible ( at the flat surface corresponding to the bottom of the pot ). Around the edge of the base of the soil ball, the roots have formed a closely packed mass. This plant should be repotted or planted out into the ground.
Model release not required. Property release not required.