Leaf responses to drought stress in Mediterranean accessions of Solanum lycopersicum: anatomical adaptations in relation to gas exchange parameters

Abstract

In a previous study, important acclimation to water stress was observed in the Ramellet tomato cultivar (TR) from the Balearic Islands, related to an increase in the water-use efficiency through modifications in both stomatal (gs) and mesophyll conductances (gm). In the present work, the comparison of physiological and morphological traits between TR accessions grown with and without water stress confirmed that variability in the photosynthetic capacity was mostly explained by differences in the diffusion of CO2 through stomata and leaf mesophyll. Maximization of gm under both treatments was mainly achieved through adjustments in the mesophyll thickness and porosity and the surface area of chloroplasts exposed to intercellular airspace (Sc). In addition, the lower gm/Sc ratio for a given porosity in droughtacclimated plants suggests that the decrease in gm was due to an increased cell wall thickness. Stomatal conductance was also affected by drought-associated changes in the morphological properties of stomata, in an accession and treatmentdependent manner. The results confirm the presence of advantageous physiological traits in the response to drought stress in Mediterranean accessions of tomato, and relate them to particular changes in the leaf anatomical properties, suggesting specific adaptive processes operating at the leaf anatomical level.

Quantitative Genetic Analysis Indicates Natural Selection on Leaf Phenotypes Across Wild Tomato Species (Solanumsect.Lycopersicon; Solanaceae)

“…These traits were included to evaluate the strength of general associations between leaf epidermal traits and to assess an hypothesis that changes in SR could be a byproduct of selection on other developmentally integrated epidermal traits, such as trichomes. Tomato leaves are bifacial, with distinct internal (mesophyll) layers (Kebede et al 1994;Galmés et al 2013) and epidermal anatomies on each surface. However, if general developmental pleiotropy determines the anatomy of abaxial (lower) and adaxial (upper) epidermises, then species with high SR (i.e., more even distribution of stomata between upper and lower leaf surfaces) should show similar patterns in other epidermal traits such as trichomes.…”

Pectin Methylesterification Impacts the Relationship Between Photosynthesis and Plant Growth in Arabidopsis thaliana

“…Leaf growth can occur in the form of leaf area or LMA (Lambers et al, 2008;Weraduwage et al, 2015). The size and shape of cells in the leaf mesophyll can have a significant impact on: (1) projected or effective leaf surface area, which is the leaf area capable of intercepting light; (2) leaf mass per unit leaf area or LMA; (3) CO 2 conductance from the external environment through intercellular air spaces into chloroplasts in mesophyll cells; and (4) surface area of mesophyll cells and chloroplasts exposed to intercellular airspaces (Honda and Fisher, 1978;Evans et al, 1994;Galmés et al, 2013). The plant cell wall controls expansion and positioning of cells of photosynthetic tissues and therefore, changes in cell wall properties will have a direct impact on the above properties.…”

Funtional Ecology of fronds in Iberian saxicolous ferns

“…These assumptions derive from the water resources limitation that plants have to deal with in the Mediterranean locations, as water is usually one of the factors which that most limits production in terrestrial plants (Galmés et al 2007;Galmés et al 2013;Joffre et al 1999) and is also the factor that most often determines character selection in plants (Terradas, 2001). Faced to water stress, vegetal productivity will be limited and plants will adopt strategies to retain the resources.…”