Open Access Repository

Solar radiation as a factor in the evolution of scleromorphic leaf anatomy in Proteaceae


Downloads per month over past year

Jordan, GJ, Dillon, RA and Weston, PH 2005 , 'Solar radiation as a factor in the evolution of scleromorphic leaf anatomy in Proteaceae' , American Journal of Botany, vol. 92, no. 5 , pp. 789-796 .

[img] PDF
Proteaceae_phot...pdf | Request a copy
Full text restricted
Available under University of Tasmania Standard License.

Official URL:


Species of the major Southern Hemisphere family, Proteaceae, have many scleromorphic anatomical structures in their leaves. Many of these structures (very thick cuticles and five anatomically distinct structures beneath the epidermis) are associated with the leaf surface exposed to direct light. These structures increase the path through which solar radiation must pass before reaching the mesophyll.
In this study, such structures are proposed to protect the mesophyll from excess solar radiation, including photosynthetically active, ultraviolet, and possibly infrared radiation. Scleromorphic structures of the upper leaf surface and nonscleromorphic photoprotective
structures (dense trichomes and papillae of the upper surface) occur almost exclusively in open vegetation. Open vegetation species of Proteaceae occur in oligotrophic and/or cold and/or dry places, where protection from light in excess of photosynthetic capacity and damage from ultraviolet light should be most important. Data from 123 species and a supertree constructed from available
molecular phylogenies are used to show that the proposed photoprotective structures evolved many times within Proteaceae. In tests of correlated evolution, the proposed photoprotective structures are significantly associated with open vegetation, but not with dry habitats.

Item Type: Article
Authors/Creators:Jordan, GJ and Dillon, RA and Weston, PH
Keywords: anatomy; cuticle; photoprotection; Proteaceae; scleromorphy; sclerophylly; ultraviolet; xeromorphy
Journal or Publication Title: American Journal of Botany
Additional Information:

The definitive version is available online at

Item Statistics: View statistics for this item

Actions (login required)

Item Control Page Item Control Page