Photosynthetic characteristics of Sonoran Desert winter annuals
- 87 Downloads
Photosynthesis in Sonoran Desert winter annuals appeared to be similar to those observed in other C3 photosynthetic pathway herbs, although photosynthetic capacities ranged from 18 to 65 μmol CO1 m-2 s-1 under natural conditions. The higher photosynthetic capacities were associated with high leaf conductances to water vapor (up to 39 mm s-1). Leaf Kjeldahl nitrogen contents were high, ranging up to 44.9 mg g-1. We suggest that the high photosynthetic capacities in several species may be related to resource availability and enable successful exploitation of the short, unpredictable growth periods experienced by these annuals. Although photosynthetic rates in desert winter annuals spanned a wide range, the relationship between leaf conductance and maximum photosynthesis appeared simiar to that of other C3 vascular plants. It is possible that the resulting constant intercellular, CO2 concentrations were related to minimizing excessive water loss, while not severely imposing limitations to photosynthetic gains.
KeywordsPhotosynthetic Rate Leaf Conductance Maximum Photosynthetic Rate Specific Leaf Weight High Photosynthetic Capacity
Unable to display preview. Download preview PDF.
- Ehleringer J (1983b) Adaptations of annuals and perennials to warm deserts. In B Chabot and HA Mooney (eds), Physiological Ecology of North American Plant Communities. Chapman and Hall Ltd, LondonGoogle Scholar
- Ehleringer J, Cook, CS (1980) Measurements of photosynthesis in the field: utility of the CO2 depletion technique. Plant, Cell and Environment 3:479–482Google Scholar
- Körner C, Scheel JA, Bauer H (1979) Maximum leaf diffusive conductance in vascular plants. Photosynthetica 13 (1):45–82Google Scholar
- Lillevik HA (1970) The determination of total organic nitrogen, p 601–616. In: Joslyn MA (ed), Methods in Food Analysis. Academic Press, New YorkGoogle Scholar
- Seemann JR, Berry JA, Dowton WJS (1980a) Seasonal changes in high-temperature acclimation of desert winter annuals. Carnegie Inst Wash Yb 79:141–143Google Scholar
- Seemann JR, Field C, Berry JA (1980b) Photosynthetic capacity of desert winter annuals measured in situ. Carnegie Inst Wash Yb 79:146–147Google Scholar
- Sestak, Z, Catsky J, Jarvis PG (1971) Plant Photosynthetic Production: Manual of Methods. Junk The HagueGoogle Scholar
- Shreve F, Wiggins IL (1964) Vegetation and Flora of the Sonoran Desert. Stanford Univ. Press, StanfordGoogle Scholar