KOPTUR, SUZANNE. Department of Biological Sciences, Florida International University, Miami, FL 33199, USA. - The floral biology and breeding system of Jacquemontia curtissii, an endemic morning glory of south Florida pine rocklands.
Field-collected individuals of Jacquemontia curtissii
(Convolvulaceae), a perennial herb, were cultivated in a greenhouse to
control conditions for hand-pollinations and floral measurements. This
work was companion to field studies on the effects of habitat
fragmentation on pollination of this species, after attempts to
determine compatibility were complicated by field conditions. Flowers
last one day, open from dawn through mid-morning, and produce nectar
as reward for pollinators. Each flower contains from .25 - 1
microliter of nectar, from 22-50% sugar on a wt/wt basis; larger
nectar volumes usually correspond to lower sugar concentrations.
Flowers on each individual were subjected to one of four treatments:
not manipulated (autogamy), anthers removed (apomixis), selfed, or
crossed. Five flowers on each plant received each treatment, except
for crosses, where ten flowers were used, crossed with different
individuals. Results show the species to be highly self-incompatible,
and the lack of pollen tube growth in all treatments except compatible
crosses demonstrates sporophytic self-incompatibility. Fruit set
observed in the field can therefore be interpreted as evidence of
pollinator activity, and successful transfer of pollen from another
compatible individual.
Key words: breeding systems, Convolvulaceae, floral biology, flower, nectar, pollination