title: The effect of photoperiod on the levels of seven endogenous gibberellins in the long-day plant Agrostemma githago L.
abstract: The following seven gibberellins (GAs) have been identified by gas chromatography-mass spectrometry in shoots and leaves of the long-day plant Agrostemma githago: GA53, GA44, GA19, GA17, GA20, GA1, and 3-epi-GA1. The levels of these compounds were measured, using selected ion monitoring, during photoperiodic induction. The levels of GA44, GA19, GA17, and GA20 all increased to a peak at eight long days (LD), followed by a decline, while the levels of GA1 and 3-epi-GA1 did not reach a peak until 12 LD. The level of GA53 remained steady over the first 10-12 LD. Later in the LD treatment the levels of GA53, GA44, GA19, and GA17 increased again. The rate of metabolism of all GAs except GA53 was higher after 12-16 LD than under short days. These data thus provide indirect evidence for an effect of photoperiodic induction on GA turnover in A. githago.
authors.affiliation: MSU-DOE Plant Research Laboratory, Michigan State University, 48824, East Lansing, MI, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Jones
authors.forename: J A
authors.initials: JA
authors.lastname: Zeevaart