[Effects of various planting densities on dynamic growth rhythm and root yield of Isatis indigotica]

To study the effects of various planting densities on dynamic growth and root yield of Isatis indigotica.

The planting samples were collected to measure the growth period of each organ.

Under different planting densities, both main root length and breadth exhibited a trend of "fast-slow" by stages. However, the number of individual plant leaves were showed a trend of "slow-fast" on growth period. Meanwhile, the leaf length and breadth were exhibited a trend of "increase-decrease". The increase of dry leaf, dry root and whole plant dry matter was faster during the period of 65-76 days after seeding. The differences of root and leaf yields under various densities were significant. Planting densities has a great effect on yield of root. It must be shown that there was a positive development between the individual plant and colony. According to the dry matter of root and leaf, treatment B (i.e., 7 cm x 25 cm) was good choice.