title: Structural assessment of the impact of environmental constraints on Arabidopsis thaliana leaf growth: a 3D approach.
abstract: Light and soil water content affect leaf surface area expansion through modifications in epidermal cell numbers and area, while effects on leaf thickness and mesophyll cell volumes are far less documented. Here, three-dimensional imaging was applied in a study of Arabidopsis thaliana leaf growth to determine leaf thickness and the cellular organization of mesophyll tissues under moderate soil water deficit and two cumulative light conditions. In contrast to surface area, thickness was highly conserved in response to water deficit under both low and high cumulative light regimes. Unlike epidermal and palisade mesophyll tissues, no reductions in cell number were observed in the spongy mesophyll; cells had rather changed in volume and shape. Furthermore, leaf features of a selection of genotypes affected in leaf functioning were analysed. The low-starch mutant pgm had very thick leaves because of unusually large palisade mesophyll cells, together with high levels of photosynthesis and stomatal conductance. By means of an open stomata mutant and a 9-cis-epoxycarotenoid dioxygenase overexpressor, it was shown that stomatal conductance does not necessarily have a major impact on leaf dimensions and cellular organization, pointing to additional mechanisms for the control of CO(2) diffusion under high and low stomatal conductance, respectively.
authors.affiliation: Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, UMR 759, INRA-SupAgro, Place Viala, 34060 Montpellier, Cedex 1, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Wuyts
authors.forename: Catherine
authors.initials: C
authors.lastname: Massonnet
authors.forename: Myriam
authors.initials: M
authors.lastname: Dauzat
authors.forename: Christine
authors.initials: C
authors.lastname: Granier
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology* / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D001696:Biomechanical Phenomena / Q000528:radiation effects; D002452:Cell Count; D048430:Cell Shape / Q000528:radiation effects; D048429:Cell Size / Q000528:radiation effects; D004777:Environment; D005838:Genotype; D006813:Humidity; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008027:Light; D058503:Mesophyll Cells / Q000166:cytology / Q000528:radiation effects; D009154:Mutation / Q000235:genetics; D009928:Organ Specificity / Q000528:radiation effects; D010788:Photosynthesis / Q000528:radiation effects; D018515:Plant Leaves / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development* / Q000528:radiation effects; D054046:Plant Stomata / Q000033:anatomy & histology / Q000502:physiology / Q000528:radiation effects; D012987:Soil; D013213:Starch / Q000378:metabolism; D014867:Water
chemical_list: D012987:Soil; D014867:Water; D013213:Starch