Non-photosynthetic light requirement for the development of flowers in Chenopodium rubrum, a short-day plant

Abstract

Seedlings of Chenopodium rubrum do not develop flowers in continuous darkness even with high concentrations of sucrose in the medium. Irradiation of plants with 5 min of red and (or) far-red wavelengths on the 6th to 8th days of darkness leads to a high degree of flowering. This non-photosynthetic light effect on flowering can be duplicated by a gibberellic acid (GA3) and kinetic application. The lack of flowering in continuous darkness appears to be due to a low apical activity. Red and far-red irradiation (via the formation of a critical level of PFR) and the plant growth hormones may have promoted flowering of C. rubrum by stimulating apical activity. Thus, light may be required after induction of flowering, not only to provide photosynthetic energy substrates but also to create a favorable balance of growth hormones that are required to maintain optimal apical activity essential for flower development.