Stomatal characteristics of riparian poplar species in a semi-arid environment.
by Pearce D. W., Millard S., Bray D. F., Rood S. B. (2006)
in Tree Physiology, 26: 211-218. – http://dx.doi.org/10.1093/treephys/26.2.211 –
We investigated stomatal characteristics of these poplars in 51 genotypes collected across the range of ecoregions and grown in a semi-arid common garden. Stomatal length differed among genotypes within species but did not differ among species, ranging from 19 to 22 μm. Total stomatal densities (adaxial plus abaxial) differed among genotypes within species but were similar among species (290–420 stomata mm−2).
Single-surface stomatal densities differed among species and consequently, the ratio of adaxial:abaxial stomatal density also differed, ranging from 0.94 for P. deltoides to 0.27 for P. balsamifera, with intermediate stomatal density ratios in P. angustifolia and hybrids.
In a subsequent study of a subset of the same genotypes, stomatal density was correlated with stomatal conductance (r2 = 0.75) and the conductance ratios differed among species in the same manner as the stomatal density ratios.
We conclude that:
(1) diverse poplar genotypes respond similarly to a semi-arid environment by producing comparatively small and dense stomata;
(2) differences in stomatal density underlie differences in stomatal conductance and differences among species in stomatal density ratio or conductance ratio may reflect adaptation to climatic differences among ecoregions; and
(3) there is substantial variation in stomatal characteristics within and among species and hybrids in this area that could be useful for the selection and breeding of poplars adapted to different climatic conditions.