Auxin perception and polar auxin transport are not always a prerequisite for differential growth.
Using time-lapse photography, we studied the response kinetics of low light intensity-induced upward leaf-movement, called hyponastic growth, in Arabidopsis thaliana. This response is one of the traits of shade avoidance and directs plant organs to more favorable light conditions. Based on mutant- and pharmacological data we demonstrated that among other factors, functional auxin perception and polar auxin transport (PAT) are required for the amplitude of hyponastic growth and for maintenance of the high leaf angle, upon low light treatment. Here, we present additional data suggesting that auxin and PAT antagonize the hyponastic growth response induced by ethylene treatment. We conclude that ethylene- and low light-induced hyponastic growth occurs at least partly via separate signaling routes, despite their strong similarities in response kinetics.
van Zanten
Martijn
M
Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands.
Millenaar
Frank F
FF
Cox
Marjolein C H
MC
Pierik
Ronald
R
Voesenek
Laurentius A C J
LA
Peeters
Anton J M
AJ