Andromonoecy and club-like organ development in the annual endemic
Iranian Dicyclophora persica (Apiaceae)
Abstract
Species of Apiaceae despite uniform floral structure show great
variation in floral morphs and sexual distribution. In the present
study, ontogeny of the diclinous flowers within “cage-like”
inflorescence of the andromonoecious Dicyclophora persica Boiss.,
studied using scanning electron microscopy (SEM), in order to recognize
whether they follow the same ontogenetic processes. The development of
interesting unusual club-like organ in center of the umbel, furthermore,
studied. The floral organs in diclinous flowers initiated from the
common sectorial group-like primordia. Petals initiated as clockwise
direction and stamens as modified helical pattern. Perfect flowers,
despite sepal suppression, synchronized with staminate flowers in
initiation of petals, stamens and carpels. In staminate flowers, in
turn, two prominent sepals arise subsequently after initiation of
stamens. Only in late stages, ovules get aborted. The club-like organ
initiated from a naked receptacle that has no resemblances to the
umbellets or flowers. The prolonged spatial constrains imposed by
massive staminate flowers are responsible for suppression of sepals and
sessile status of perfect flowers. Considering the ovules suppression,
staminate flowers may likely adopt to conserve the perfect flowers from
exposing in extreme environmental conditions, but not as substitution
for perfect flowers.