Lg. Leroux et al., THE TRANSMITTING TRACT IN GLORIOSA-SUPERBA - STRUCTURE, PISTIL EXUDATE AND POLLEN-TUBE GROWTH, South African journal of botany, 62(4), 1996, pp. 204-208
The structure of the pistil exudate, transmitting tissue and pollen tu
be growth of Gloriosa superba L. were studied. Flowers are protogynous
, as the stigmas become receptive one day prior to anther dehiscence,
and remain receptive for at least four days. Neutral red and auramine
O proved to be useful for the indication of stigma receptivity, The st
igma is wet while the papillae and canal cells form slight interior ce
ll wall ingrowths reminiscent of transfer cells. Pistil exudate is mos
tly lipidic, confirmed by the prevalence of endoplasmic reticulum in t
he cytoplasm. The canal exudate includes substances derived from degen
erating canal cell walls and lipid-like vesicles breaking down into fi
ne fibrillar matter possibly associated with the pollen tube cell wall
. Pollen tubes grow in close association with the stylar secretion, re
aching most ovules, even though pollen tube numbers decrease on their
way down the stylar canal. Callose deposition in the nucellus of some
self-pollinated ovules could be indicative of a partly pre-zygotic gam
etophytic self-incompatibility system.