Comparative analysis of the leaf anatomy of Echinacea purpurea and E. pallida

Abstract

This article contains a comparative analysis of the anatomical structure of the rosette and stem leaves of Echinacea purpurea and E. pallida. The plants were grown on the experimental site of the Siberian Botanical Garden, located in the southeastern part of Tomsk (Western Siberia). Temporary preparations of the leaves were prepared by cutting them on a freezing microtome MZ-2. Photographs of leaf microscopy and microscopic measurements were made on a light microscope. Anomocyte type of stomatal complex is characteristic for the studied species. Leaves of the studied species are amphistomatic, rosette leaves of E. purpurea are hypostomatic. The stomatal index of E. purpurea was 1.5 (stem leaves, upper epidermis) and 24.4–25.5 (lower epidermis). In the leaf blade of E. purpurea, the signs are revealed as mesomorphic (the presence of relatively large dorsoventral leaves, moderate development of integumentary, conducting and mechanical tissues) and a xeromorphic-heliomorphic structure. A complex of xeromorphic-heliophytic features of the E. pallida leaf has been identified, which increase its drought resistance; the mean values of the stomatal index of the upper and lower epidermis were 24.8–28.7. There are 10 characteristics that have significant differences in mean values when comparing leaves of E. purpurea and E. pallida: the size of the stomata of the lower epidermis, the thickness of the mesophyll of the leaf, its layers and the leaf laminae free of the vascular bundle, the area of the vascular bundle and their constituents.