Auxin is well known to be implicated in developmental processes such as stem
elongation, phototropism, gravitropism, vascular tissue differentiation
and cell expansion. In pea endogenous IAA was increased under
EOD-FR (Behringer and Davies, 1992). Up-regulation of auxininduced
genes under low irradiance and low R:FR ratio resulted
in increased hypocotyl elongation in A. thaliana (Steindler et al.,
1999; Vandenbussche et al., 2003).