Summary
Proliferation of roots in organic matter is an important component of tropical nutrient cycling. In an attempt to define possible mechanisms controlling this proliferation, an experiment was conducted in which seedlings of the legume Clitoria racemosa were planted in vessels with sterilized partially decayed leaves of the same species. One half of the vessels was inoculated with a material containing litter bacteria and fungi and the other half with sterilized portions of the same material. Those having received live inoculum produced 106±30 root tips per plant against 60 ± 12 with sterilized inoculum. It is concluded that a biotic component of decomposing organic matter is able to induce branching of roots, probably through production of a hormone such as ethylene or an auxin.