Control of Growth and Metabolite Production in Persicaria Tinctoria Using Extremely Dark Light

Maeda A, Mashima R, Kimura Y, Tanikawa K, Bunya M and Kajiyama H

Published on: 2024-03-25

Abstract

Light is an important environmental factor that has a powerful influence on plant growth and development and is especially important for indoor plant cultivation. We found that weak light, which contributes little to photosynthesis itself, greatly promote plant growth. In this study, we investigated the effects of extremely dark light (EDL) on the growth and production of specific metabolites in Persicaria tinctoria in indoor cultivation. EDL is weak (0.01 μmol photons/m²/s), but its intensity changes rapidly within a few tens of microseconds. Our results demonstrated that EDL increased the weight of fresh leaves and indican by 2.3 times (vs. control). Indicans are synthesized using a combination of glucose and indoxyl groups. The increase in total indican weight and fresh leaf weight under EDL irradiation indicates that EDL stimulates the rate of photosynthesis, and that the increased glucose is equally distributed in translocation and specific metabolic pathways. Therefore, we hypothesized that photosynthetic starvation caused by EDL triggers chlorophyll synthesis and discuss the effects of EDL irradiation on P. tinctoria in terms of its response to a survival crisis.