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Sarah S. Kreunen

Project Topic / Abstract:

“Pollen and Anther Development in the American Lotus (Nelumbo lutea)”

Nelumbonaceae is a small family of aquatic flowering plants comprised of two species, Nelumbo nucifera and Nelumbo lutea. Nelumbo nucifera, the Indian or sacred lotus is found throughout Asia and Australia; while N. lutea, the American lotus or water chinquapin, occurs in eastern and southern North America. Traditionally, the lotus plays a symbolic role in Hinduism and Buddhism and is used in some Asian cultures as a source of food and medication. In addition to these factors of more colloquial interest, Nelumbo and members of closely related waterlily families are believed to occupy a phylogenetically important position at the base of angiosperms. Characters of evolutionary significance in phylogenetic studies are the ontogeny of pollen and anthers. Prior to this investigation, little was known about these events in Nelumbo. The focus of this presentation will be these events which have now been morphologically documented utilizing scanning electron microscopy, transmission electron microscopy, and light microscopy. Several stages have been documented in the development of pollen. These include sporogenous tissue, microspore mother cells, tetrads, free spores, and mature pollen grains. The deposition of the layers in the pollen wall and the morphology of mature pollen grains have also been evaluated. Further, the morphology and developmental changes in the anther have been documented. These include number of cell layers composing the anther wall; tapetum type and pattern of its maturation and degradation; and endothecial thickenings, including type and location. The present investigation is the first to employ electron microscopy in the study of anther and pollen development in N. lutea. Moreover, only three studies have ultrastructurally examined pollen development in related waterlilies.

Publications:

  • Kreunen, S. S. and J. M. Osborn. 1999. Pollen and anther development in Nelumbo (Nelumbonaceae). American Journal of Botany 86: 1662-1676. (Including color cover of journal issue for December 1999). Cover | Article (PDF)

Presentations:

1997

  • National Conference on Undergraduate Research (Austin, TX)
  • Truman Undergraduate Research Symposium (Kirksville, MO)
  • Sigma Xi Student Research Symposium (Kirksville, MO)

1998

  • Pollen and Spores: Morphology and Biology – Conference (London & Kew, UK)
  • Missouri Academy of Science (St. Joseph, MO)
  • Truman Undergraduate Research Symposium (Kirksville, MO)
  • Sigma Xi Student Research Symposium (Kirksville, MO)
  • Tri-Beta Biological Honor Society Regional Meeting (Steelville, MO)
  • Undergraduate Research Poster Day at the State Capital (Jefferson City, MO)
  • Expanding Horizons. Undergraduate Research at Truman State University.
  • Truman Review Summer 1998, Vol. 3, No. 1. Article