Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

A Comparative Study of the Fracture Properties of Five Grasses

W. Wright and A. W. Illius
Functional Ecology
Vol. 9, No. 2 (Apr., 1995), pp. 269-278
DOI: 10.2307/2390573
Stable URL: http://www.jstor.org/stable/2390573
Page Count: 10
  • Read Online (Free)
  • Download ($18.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
A Comparative Study of the Fracture Properties of Five Grasses
Preview not available

Abstract

1. The mechanical properties of plants constrain herbivory. Fracture properties of five species of grass were measured using tests which fractured leaves, pseudostems and whole tillers in tension (mode 1) and in out of plane shear (mode III). Force (F), energy to fracture (U) and energy per unit area (U/A) were caluclated from force-displacement curves. 2. Fracture properties varied widely, depending on species, morphological unit, sclerenchyma or fiber content, and whether the gross was fractured in tension or in shear. 3. Older leaves contain more sclerenchyma than younger leaves, resulting in higher F, U and U/A. 4. Pseudostem is tougher and stronger than leaf whether fractured in shear or in tension, owing to its complex structure and capacity for plastic deformation, larger cross sectional area, and higher fibre content. 5. Entire tillers tested under tension required much less energy to fracture than leaf or pseudostem. 6. Fracture occurs at a zone of weakness at the intercalary meristem and it is argued that this is an evolutionary advantage to grass species which are commonly grazed. The fibre content of grasses increases the difficulty both of harvest and digestion by herbivores.

Page Thumbnails

  • Thumbnail: Page 
269
    269
  • Thumbnail: Page 
270
    270
  • Thumbnail: Page 
271
    271
  • Thumbnail: Page 
272
    272
  • Thumbnail: Page 
273
    273
  • Thumbnail: Page 
274
    274
  • Thumbnail: Page 
275
    275
  • Thumbnail: Page 
276
    276
  • Thumbnail: Page 
277
    277
  • Thumbnail: Page 
278
    278