FACTORS INFLUENCING NITROGEN FIXATION BY SEVERAL WOODY SHRUBS AND TREES

The influences of temperature, light intensity, solar radiation and moisture on nitrogen fixation that occurs in root nodules of several species of trees and shrubs were investigated. Excised nodules of nine plant species have been characterized as to the effect of temperature on their ability to reduce acetylene (C2H2) to ethylene (C2H4). Nodules from the nonlegumes, with the exception of H. rhamnoides, have a maximum C2H2-reduction rate at 30 C. A maximum C2H2-reduction rate for nodules from H. rhamnoides and the legume, R. pseudoacacia, occurs at 20 C. At temperatures near freezing the C2H2-reducing rate is very low. Reducing activity decreased sharply between 30 C and 40 C for all species exept E. angustfolia. When A. glutinosa and E. umbellata were grown in growth chambers under 950 and 4200 ft-candle light intensities, there was no increase in C2H2-reducing ability by nodules from plants under the higher light intensity versus plants grown under the lower light intensity. Field grown A. glutinosa did indicate response in C2H2-reducing ability due to fluctuation in solar radiation or temperature or both when the plants were not under moisture stress. Ample soil moisture was needed for nodules of A. glutinosa to be responsive to solar radiation or temperature. Nodules from container grown E. umbellata did not respond with increases in C2H2 reduction when solar radiation or temperature increased. The lack of response is in part believed to be due to moisture stress.

  • Supplemental Notes:
    • Conducted in cooperation with US DOT/FHWA.
  • Corporate Authors:

    Purdue University/Indiana Department of Transportation JHRP

    Purdue University, School of Civil Engineering
    West Lafayette, IN  United States  47907-1284
  • Authors:
    • Mcniel, R E
  • Publication Date: 1976-1

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 114 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00131149
  • Record Type: Publication
  • Report/Paper Numbers: JHRP-76-6 Intrm Rpt.
  • Contract Numbers: HPR-1(12) Part II
  • Files: TRIS
  • Created Date: May 14 1976 12:00AM