Extrinsic and Intrinsic Factors Controlling Reproduction in an Annual Plant

The objectives of the study were to (1) determine what factors limit fruit and seed production in the annual legume Cassia fasciculata Michx., and (2) determine the extent of and basis for selective fruit maturation in this plant species. Cassia fasciculata is an herbaceous plant that inhabits prairies, open woods, and waste places. Manual addition of pollen to flowers in the field increased the number of fruit initiated per inflorescence, but did not increase the number of fruit matured, suggesting that fruit production was not pollinator limited. Removal of rapidly growing fruits resulted in growth and maturation of fruits that normally would not have matured, suggesting that resources limited fruit production. In four populations studied 24 - 70% of initiated fruits matured, 12 - 40% were aborted or died, 3 - 31% were still developing at the time of plant death, and 6 - 12% were lost to predators. In fruits that matured, between 23 and 73% of initiated seeds reached maturity, 22 - 43% were aborted, and 0 - 49% were lost to seed predators. The data indicate that seed production was limited by either resources or seed predators. Demographic studies indicated that resource limitation resulted from either resource shortages or insufficient time to acquire these resources.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Botany

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Lee, Thomas Dale

• Biology, Botany

Language dc:language

eng

Identifier

(UMI)AAI8108577

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/68205