1. Drought limitation of photosynthesis differs between C.
- Author
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TAYLOR, S. H., RIPLEY, B. S., WOODWARD, F. I., and OSBORNE, C. P.
- Subjects
EFFECT of drought on plants ,PHOTOSYNTHESIS ,PHYLOGENY ,GRASSES ,NITROGEN ,CHLOROPHYLL ,PLANT species - Abstract
Phylogenetic analyses show that C grasses typically occupy drier habitats than their C relatives, but recent experiments comparing the physiology of closely related C and C species have shown that advantages of C photosynthesis can be lost under drought. We tested the generality of these paradoxical findings in grass species representing the known evolutionary diversity of C NADP-me and C photosynthetic types. Our experiment investigated the effects of drought on leaf photosynthesis, water potential, nitrogen, chlorophyll content and mortality. C grasses in control treatments were characterized by higher CO assimilation rates and water potential, but lower stomatal conductance and nitrogen content. Under drought, stomatal conductance declined more dramatically in C than C species, and photosynthetic water-use and nitrogen-use efficiency advantages held by C species under control conditions were each diminished by 40%. Leaf mortality was slightly higher in C than C grasses, but leaf condition under drought otherwise showed no dependence on photosynthetic-type. This phylogenetically controlled experiment suggested that a drought-induced reduction in the photosynthetic performance advantages of C NADP-me relative to C grasses is a general phenomenon. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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