COONS, JANICE M.*, HENRY R. OWEN, JENNIFER L. FRANKLIN, AND JOHN E. EBINGER. Biological Sciences Department, Eastern Illinois University , Charleston, IL 61920. - Reproductive potential of Silvery Bladderpod (Lesquerella ludoviciana).
Silvery bladderpod (Lesquerella ludoviciana) is an endangered plant in
Illinois where plants are at the eastern edge of their geographic
range, occurring in blowout areas of recovering sand prairies at the
Henry Allan Gleason Nature Preserve. Little is known about its
reproductive potential in these areas. The objective of this study
was to characterize population size, production of reproductive
structures, and viability of seeds. In June 1999, three populations
were identified within the Preserve. For each population, plants with
and without fruits (no flowers present) were counted, and population
areas were determined. Seedstalks/plant, fruits/seedstalk, and
seeds/fruit were counted. Seeds were germinated on filter paper in
Petri dishes at 25C. The three populations varied in size from 275 to
2050 m2 with a total area of nearly 3000 m2. Plant numbers were 900,
225, and 10,300 in the smallest, intermediate, and largest areas,
respectively. The percentage of reproductive plants was lowest (28%)
in the largest area and highest (88%) in the smallest area.
Reproductive plants produced 6.5 seedstalks/plant (from 1 to 20). An
average of 17.3 fruits/seedstalk (from 0 to 43) and 2.4 seeds/fruit
(from 0 to 7) were produced. On seedstalks, seeds matured first on
the lower part and last on the upper part. Total seed production for
all three populations was estimated at nearly 1,200,000 seeds. Seeds
germinated without any treatments to break dormancy. In summary,
reproductive potential does not appear to be limited by seed
production or by seed viability. Rather, reproductive potential in
silvery bladderpod must be limited by other factors.
Key words: Brassicaceae, germination, Lesquerella ludoviciana, reproductive potential, Silvery Bladderpod