Physiological and Ultrastructural Characteristics of Leaves of Eucalyptus Clones Destined for Matrix Selection

Introduction: In order to characterize Eucalyptus species for diverse purposes, it is necessary to analyze it in an ultrastructural and physiological way, aiming a faster and more precise selection of the possible properties and utilities of the species.

Objective: The objective was to observe the physiological and ultrastructural characteristics of leaves of eucalyptus clones destined for matrix selection.

Materials and Methods: The following clones were used: E54, E20, E24, E45, AEC063 and E16. The following variables were evaluated: CO2 assimilation rate expressed by area (A − μmol CO2 m−2 s−1), transpiration (E − mmol H2O m−2 s−1), stomatal conductance (GS − mol H2O m−2 s−1), internal CO2concentration in the substomata chamber (Ci − μmol mol−1), phloem diameter of leaf (PDL), xylem diameter of leaf (XDL), thickness of palisade parenchyma (PP), abaxial (ABET) and adaxial (ADET) surface thickness, inferior face of stomata functionality (IFFS) and stomata density (SD). Results: The physiological and morphological variations were observed among the clones tested. Conclusion: Clone E16 presented greater leaf transpiration, stomata conductance, the rate of photosynthesis and efficient water use, physiological, palisade parenchyma and stomata functionality. Clone E16 presented lower Adaxial epidermis thickness (AD) and Abaxial epidermal thickness (AB).