The modified gibberellins, 16-methyl-16,17-dihydro-GA(5), 16,17-methano-16,
17-dihydro-Gh(5), 16,17-methano-16,17-dihydro-GA(3) and several halogenated
derivatives of 16,17-methano-16,17-dihydro-GA(3) and GA(5) were prepared a
nd tested for bioregulating properties in Lolium temulentum. The effects ra
nged from the promotion of both stem elongation and flowering, the promotio
n of flowering but not elongation, and vice versa, the inhibition of stem e
longation combined with the promotion of flowering, and the inhibition of b
oth. (C) 1998 Elsevier Science Ltd. All rights reserved.