TIME RESPONSES AND THE SUSCEPTIBILITY OF ROADSIDE PLANTS TO GROWTH REGULATIONS

Times responses, particularly daily oscillations, of seven species of plants were studied. Five of the species were weeds: Ambrosia artemisiifolia L., common ragweed; Ambrosia trifida L., giant ragweed; Cirsium arvense (L.) Scop., Canada thistle; Euphorbia esula L., leafy spurge; and Taraxacum officiale Weber, common dandelion. Two were desirable as roadside ground cover: Medicago sativa L., alfalfa, and Trifolium pratense L., red clover. Methods were developed for germinating weed seeds, a process which is often difficult to accomplish in a laboratory. A chlorophyll assay that was selected and modified for the study should be valuable in monitoring the status of injury to a variety of roadside plants. Variations in plant populations and the lack of good statistical evidence were important factors in not being able to designate any one time of day to be consistently better for controlling weeds by 2, 4-dichlorophenoxyacetic acidu (2,4-D) under controlled envirnmental conditions. It is possible that changes which take place throughout the day in leaf orientation could be an important factor when considering procedures for controlling roadside weeds, such as sicklepod in southern states or velvetleaf in Minnesota. (FHWA)

  • Corporate Authors:

    University of Minnesota, St Paul

    Department of Botany
    St Paul, MN  United States  55101

    Minnesota Department of Transportation

    Transportation Building, 395 John Ireland Boulevard
    St Paul, MN  United States  55155
  • Authors:
    • Koukkari, W L
  • Publication Date: 1980

Media Info

  • Pagination: 22 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00322708
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: FHWA-MN-80-05 Final Rpt.
  • Contract Numbers: Inv No. 649
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Mar 12 1981 12:00AM