In cowpea (Vigna sinensis) enhanced elongation in response to EOD-FR is apparently due to reduced inactivation of GA1 as a consequence of removal of the active phytochrome form Pfr(Martínez-García et al., 2000). In hybrid aspen (Populus tremula × tremuloides) phytochrome A (PHYA) over-expression resulted in decreased shoot elongation due to reduced cell numbers and cell lengths, and this was correlated with reduced GA and IAA levels (Olsen et al., 1997).