The Epidermal Characters Of Zelkova (Ulmaceae) And Metasequoia (Taxodiaceae) And Their Stomatal Responses To Atmospheric CO₂ Concentration Change

There have been many reports about the inverse correlation between stomatal frequency of land vascular plants and CO₂ concentration, and based on it the paleo-CO₂ concentrations during Devonian to last millennium has been reconstructed. To enhance the resolution in the reconstruction of paleo-CO₂ concentrations, more plants need to be tested as proxies to signal atmospheric CO₂ concentration change.The epidermal characters and stomatal frequencies of leaves of four species in Zelkova (Ulmaceae) and Metasequoia glyptostroboides (Taxodiaceae) are studied to assess the possibility of species in Zelkova to signal atmospheric CO₂ concentration, understand the variation in the epidermal characters of M. glyptostroboides and the factors which influence stomatal density of M. glyptostroboides. The results are summarized as follows:1. Stomatal responses of species in Zelkova to atmospheric CO₂ concentration changeThe responses of stomatal frequencies (including stomatal density, SD and stomatal index, SI) of four species in Zelkova to atmospheric CO₂ concentration change are studied to assess the potential for them as atmospheric CO₂ concentration CO₂ proxies. The four species are Z. schneideriana, Z. serrata, Z. sinica in East Asia...