Acifluorfen Enhancement of Cryptochrome-Modulated Sporulation following an Inductive Light Pulse.

Acifluorfen enhancement of blue-light mediated phototropism suggested that this diphenyl-ether herbicide augments the light reaction (TY Leong, WR Briggs 1983 Plant Physiol 70: 875-881). The separation of the possible direct interaction of acifluorfen with light reactions from interactions with dark pathways has been elucidated in this paper with Trichoderma harzianum. Acifluorfen at 30 micromolar, given for 5 hours in the growth medium, stimulated the conidiation of Trichoderma in response to blue light without apparently affecting growth. Enhanced conidiation could be elicited by dipping cultures into medium with acifluorfen both before as well as 0.5 hour after inductive blue light. This postphotoinduction stimulation indicates that acifluorfen does not directly augment the effect of light by interacting with cryptochrome(s) in Trichoderma. Instead, acifluorfen most probably interacted with the dark reactions following photoinduction.