Photoenhancement by Blue Light of Organogenesis in Tobacco Pith Cultures

Abstract
Agar‐grown cultures of tobacco pith tissue (Wisconsin 38) were incubated in the dark or in the light for 36 days. With 1 μM indole‐3‐acetic acid (IAA) in the medium, considerable differentiation, including organogenesis occurred in the light, but not in the dark. Such photoenhancement of differentiation did not occur when 2.4‐dichlorophenoxy acetic acid (2,4‐D) or naphthalene acetic acid (NAA) was substituted for IAA. Blue light of greater than 12 days duration was responsible for the photoenhancement effect.