Photosynthetic adaptation to high temperatures: a field study in Death Valley, California
Bjorkman O, Pearcy RW, Harrison AT, Mooney HA. 1972. Photosynthetic adaptation to high temperatures: a field study in Death Valley, California. Science. 175(4023):786-789
Death Valley plants whose growing season is summer must have particular adaptations allowing efficient photosynthesis under extremes of heat and dryness. This investigation in July 1970 of Tidestromia oblongifolia growing in Death Valley documents the remarkable ability of this species to function as well at very high air temperatures as many others under much more temperate conditions. According to test results, this species, as well as the two others growing with it on an alluvial fan, shows the C4 photosynthetic mechanism. Its pattern, unlike that of other desert plants, lacked the typical noontime depression in photosynthesis. The authors undertook further tests to distinguish the effects of light intensity and temperature. With full sunlight, photosynthesis occurs at a higher rate as temperatures rise (up to 47: C), and falls off sharply below 44: C. With a lower light intensity, the optimum temperature also decreases. The only plants known to have higher optimum temperatures than T. oblongifolia are blue-green algae from hot springs. The existence of the C4 pathway seems to be a vital part of the adaptation, but the authors suggest that it would be important to discover if other types exist with comparable adaptations. Four graphs illustrate data.
- Type
- Journal Article
- Authors
- Bjorkman, Olle; Pearcy, Robert; Harrison, A; Mooney, Harold
- Units
- DEVA
- Keywords
- Air Temperature, Arizona honeysweet (Tidestromia oblongifolia), Death Valley National Park CA NV, Furnace Creek Death Valley National Park CA NV, Photosynthesis, Plant Studies