Gas exchange characteristics of Pinus edulis and Juniperus monosperma
Barnes FJ. 1987. Gas exchange characteristics of Pinus edulis and Juniperus monosperma. Bulletin of the Ecological Society of America. 68(3):259
A shift in the relative dominance of Pinus edulis and Juniperus monosperma is associated with a complex elevational gradient in northern New Mexico. The ecophysiological parameters contributing to this dominance pattern were studied by determining the gas exchange characteristics of the two species in response to temperature, light and water stress under controlled conditions. P. edulis has a higher photosynthetic capacity than J. monosperma, and has a tendency to form ecotypes with individuals from mesic sites having higher rates of carbon gain than xeric site individuals. J. monosperma is more drought-tolerant than P. edulis. As soil moisture decreases, zero carbon gain in J. monosperma occurs at a lower predawn leaf water potential (-4 .6 MPa) than in P. edulis (-2.2 MPa). There is no significant difference between species in- the temperature of peak carbon gain. J. monosperma has a significantly wider temperature optimum than P. edulis with the additional range being at high temperatures. The observed lower elevational limit of P. edulis coincides with its physiological tolerance of water stress as estimated by seasonal leaf carbon gain. Environmental limitations to the distribution of monosperma were not found at higher elevations where edulis is dominant.
- Type
- Journal Article
- Authors
- Barnes, Fairley
- Units
- BAND
- Keywords
- Gas Exchange, one-seed juniper (Juniperus monosperma), Physiology, Pinyon Pine (Pinus edulis), Plant Studies, Plants