The evolutionary importance of stomata and mesophyll traits on adaptation to climate changes.
1. Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno,74, Italy. 2. Institute for Sustainable Plant Protection, National Research Council of Italy (CNR-IPSP), Via Madonna del Piano 10 Sesto Fiorentino, 50019 Firenze, Italy. 3. Institute of Biosciences and BioResources (CNR-IBBR), Via Giovanni Amendola, 165/A, 70126 Bari (BA), Italy.
According to the Intergovernmental Panel on Climate Change, without mitigation actions, under the most optimistic scenario, atmospheric CO2 concentrations would reach 420 ppm by the end of the century; under the more pessimistic scenario, atmospheric CO2 concentrations would reach 1100 ppm by 2100 [1]. Therefore, it is essential to understand the impact of rising CO2 on plant growth. This is the background of the Prin project “Evolutionary implications for the development of climate resilient productive plants” (EvoPlant), which aims to elucidate patterns of plant evolution to promote the development of climate-resilient plants through the study of stomatal evolution, photosynthesis, and plant-atmosphere gas exchange. The purpose of our study is to analyze the correlation between leaf anatomy and stomatal patterning. We are currently completing morphological and anatomical analyses of the mesophyll and stomatal apparatus of 20 plant species representing an evolutionary pathway from lycophytes to dicotyledonous angiosperms, via ferns and gymnosperms. Specifically, we are examining the density, distribution, morphology, and size of stomata. These measurements will then be correlated with the surface area of the mesophyll cells exposed to the intercellular airspaces, the size of the mesophyll cells, the thickness of the mesophyll, the fraction of the volume occupied by the intercellular airspaces, and the total cross-sectional area of the cells that make up the mesophyll. A special case is represented by Triticum spp., in which we are studying, in addition, mesophyll conductance (Gm), i.e. the transport of CO2 from intercellular airspace within leaf in different CO2 concentration. These data will allow us to identify the most efficient combination of stomata-mesophyll traits for climate change resilience and it could be a bioindicator of environmental CO2 concentration.
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