1. Effects of low atmospheric CO and elevated temperature during growth on the gas exchange responses of C, C-C intermediate, and C species from three evolutionary lineages of C photosynthesis.
- Author
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Vogan, Patrick and Sage, Rowan
- Subjects
ATMOSPHERIC carbon monoxide ,GAS exchange in plants ,HELIOTROPIUM ,ALTERNANTHERA ,ACCLIMATIZATION (Plants) ,PHOTOSYNTHESIS - Abstract
This study evaluates acclimation of photosynthesis and stomatal conductance in three evolutionary lineages of C, C-C intermediate, and C species grown in the low CO and hot conditions proposed to favo r the evolution of C photosynthesis. Closely related C, C-C, and C species in the genera Flaveria, Heliotropium, and Alternanthera were grown near 380 and 180 μmol CO mol air and day/night temperatures of 37/29°C. Growth CO had no effect on photosynthetic capacity or nitrogen allocation to Rubisco and electron transport in any of the species. There was also no effect of growth CO on photosynthetic and stomatal responses to intercellular CO concentration. These results demonstrate little ability to acclimate to low CO growth conditions in closely related C and C-C species, indicating that, during past episodes of low CO, individual C plants had little ability to adjust their photosynthetic physiology to compensate for carbon starvation. This deficiency could have favored selection for more efficient modes of carbon assimilation, such as C-C intermediacy. The C-C species had approximately 50% greater rates of net CO assimilation than the C species when measured at the growth conditions of 180 μmol mol and 37°C, demonstrating the superiority of the C-C pathway in low atmospheric CO and hot climates of recent geological time. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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