Thesis Title

The Potential Allelopathic Effect of Several Grass Species on Native Missouri Prairie Plant Species

Date of Graduation

Summer 2000

Degree

Master of Science in Plant Science (Agriculture)

Department

College of Agriculture

Committee Chair

Pamela Borden

Subject Categories

Plant Sciences

Abstract

Aqueous shoot and root extracts of five grass species, Sorghastrum nutans (Indian grass), Andropogon gerardii (big bluestem), Bothriochloa bladhii (caucasian bluestem), Panicum virgatum (switch grass), and Schizachyrium scoparium (little bluestem), were tested in petri plates for two weeks for potential allelopathic effects on five native Missouri prairie plant species. The receiving species tested were Asclepias tuberosa (butterfly weed), Andropogon gerardii (big bluestem), Sorghastrum nutans (Indian grass), Panicum virgatum (switch grass), and Ratibida pinnata (gray-headed coneflower). Among the more striking results was the inhibitation of big bluestem seed germination with both caucasian bluestem aqueous shoot and root extracts. Switch grass aqueous shoot extract inhibited the gray-headed coneflower seed germination. Indian grass aqueous shoot extract enhanced the growth of butterfly weed and big bluestem shoots. There were also other enhancements and inhibitions with the aqueous shoot and root extracts, but more so with the aqueous shoot extracts. In another experiment using a peat-pot bioassay system, grass shoot and root residues (same grass species as used in petri plate experiment) were a source of leachate. The residue was mixed into the soil where native prairie species (same species as used in the petri plates) were grown for nine weeks. The gray-headed coneflower did not germinate with switch grass shoot leachate. Indian grass root leachate inhibited milkweed shoot growth. Caucasian bluestem root leachate enhanced the total dry weight of the gray-headed coneflower. The data from these experiments suggest potential allelopathic activity in the grassland community.

Copyright

© Heather N Parker

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