TY - JOUR

T1 - Photosynthetic pathway and ecological adaptation explain stomatal trait diversity amongst grasses

AU - Taylor, S. H.

AU - Franks, P. J.

AU - Hulme, S. P.

AU - Spriggs, E.

AU - Christin, P. A.

AU - Edwards, E. J.

AU - Woodward, F. I.

AU - Osborne, C. P.

PY - 2012/1

Y1 - 2012/1

N2 - • The evolution of C 4 photosynthesis in plants has allowed the maintenance of high CO 2 assimilation rates despite lower stomatal conductances. This underpins the greater water-use efficiency in C 4 species and their tendency to occupy drier, more seasonal environments than their C 3 relatives. • The basis of interspecific variation in maximum stomatal conductance to water (g max), as defined by stomatal density and size, was investigated in a common-environment screening experiment. Stomatal traits were measured in 28 species from seven grass lineages, and comparative methods were used to test for predicted effects of C 3 and C 4 photosynthesis, annual precipitation and habitat wetness on g max. • Novel results were as follows: significant phylogenetic patterns exist in g max and its determinants, stomatal size and stomatal density; C 4 species consistently have lower g max than their C 3 relatives, associated with a shift towards smaller stomata at a given density. A direct relationship between g max and precipitation was not supported. However, we confirmed associations between C 4 photosynthesis and lower precipitation, and showed steeper stomatal size-density relationships and higher g max in wetter habitats. • The observed relationships between stomatal patterning, photosynthetic pathway and habitat provide a clear example of the interplay between anatomical traits, physiological innovation and ecological adaptation in plants.

AB - • The evolution of C 4 photosynthesis in plants has allowed the maintenance of high CO 2 assimilation rates despite lower stomatal conductances. This underpins the greater water-use efficiency in C 4 species and their tendency to occupy drier, more seasonal environments than their C 3 relatives. • The basis of interspecific variation in maximum stomatal conductance to water (g max), as defined by stomatal density and size, was investigated in a common-environment screening experiment. Stomatal traits were measured in 28 species from seven grass lineages, and comparative methods were used to test for predicted effects of C 3 and C 4 photosynthesis, annual precipitation and habitat wetness on g max. • Novel results were as follows: significant phylogenetic patterns exist in g max and its determinants, stomatal size and stomatal density; C 4 species consistently have lower g max than their C 3 relatives, associated with a shift towards smaller stomata at a given density. A direct relationship between g max and precipitation was not supported. However, we confirmed associations between C 4 photosynthesis and lower precipitation, and showed steeper stomatal size-density relationships and higher g max in wetter habitats. • The observed relationships between stomatal patterning, photosynthetic pathway and habitat provide a clear example of the interplay between anatomical traits, physiological innovation and ecological adaptation in plants.

KW - C photosynthesis

KW - Cell size

KW - Climate niche

KW - Evolution

KW - Functional diversity

KW - Stomata

KW - Stomatal development

U2 - 10.1111/j.1469-8137.2011.03935.x

DO - 10.1111/j.1469-8137.2011.03935.x

M3 - Journal article

C2 - 22040513

AN - SCOPUS:84055202822

VL - 193

SP - 387

EP - 396

JO - New Phytologist

JF - New Phytologist

SN - 0028-646X

IS - 2

ER -