1. Leaves are always positively phototropic.

2. Rhodopseudomonas palustris is a Gram negative, purple, non-sulfur, phototropic bacterium, and is a metabolically versatile microbe.

3. Repelled by light; exhibiting a negative phototactic or phototropic response.

4. The microorganisms employed include mainly chemical conversion bacteria, phototropic bacteria and alga.

5. Relation between phytochrome action modes and possible multiple pathways for phototropic signal transduction was analyzed based on the experiment results.

6. There was little change of IAA on both sides of the coleoptile which was treated with phototropic stimulation.