Effects of nurse-plant canopy light intensity on shrub seedling growth.

Fulbright, T.E.
Kuti, J.O.
Tipton, A.R.
Rangeland Ecology & Management / Journal of Range Management Archives
Publication Year: 
Spiny hackberry (Celtis pallida Torr.) occurs almost exclusively beneath honey mesquite (Prosopis glandulosa Torr.) canopies. We hypothesized that maximum early seedling growth of spiny hackberry occurs at light intensities similar to those beneath honey mesquite, whereas maximum growth of huisache (Acacia smallii Isely), a plant characteristic of nonshaded habitats, occurs at light intensities near full sunlight. Photosynthetic photon flux densities (PPFD) under 4 honey mesquite canopies and in adjacent interspaces were recorded during July 1990 to July 1992. Seedling growth indices of spiny hackberry and huisache were determined at PPFDs characteristic of those found under honey mesquite canopies and in herbaceous interspaces. In contrast to our prediction, relative growth rate (Kw), net assimilation rate (NAR), and seedling mass of spiny hackberry were greater in sunlight than in shade characteristic of honey mesquite canopies. Huisache also had greater Kw, NAR, and total seedling mass in sunlight. Aggregation of spiny hackberry beneath honey mesquite canopies does not result from an ability to maintain maximum seedling growth at low light intensities.
Document Type: 
Journal Issue/Article
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Rangeland Ecology & Management (formerly the Journal of Range Management) serves as a forum for the presentation and discussion of facts, ideas, and philosophies pertaining to the study, management, ecology, and use of rangelands and their resources. The journal is peer-reviewed and provides international exchange of scholarly research and information among persons interested in rangelands. The Global Rangelands collection includes REM content up to 5 years from the current year. More recent content is available by subscription from BioOne and the Society for Range Management, and may be available at your local university library.
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