LIGHT REQUIREMENTS FOR MONOSPORE GERMINATION IN BANGIA ATROPURPUREA (RHODOPHYTA)

Monospore germination, in Bangia atropurpurea (Roth) C. Ag. [= B. fuscopurpurea (Dillw.) Lyngb.] is light‐dependent. In white light, the percent germination increases with increasing photon fluence rate until the response is saturated at 35 μmol · m⁻²· s⁻¹. At a saturating photon fluence rate in an 18:6 h L:D cycle, 9 days are required for maximum germination. Green light is the most effective spectral region for monospore germination, although the process can occur in red and blue light if sufficiently high photon fluence rates are provided. Monospore germination and photosynthetic oxygen evolution are completely inhibited by DCMU at a concentration of 1 × 10⁻⁶ M. Germination is reduced in a low CO₂ atmosphere and does not occur in the dark when glucose, maltose or inositol are supplied. It is concluded that photosynthesis is required for monospore germination.