Using leaf micromorphology as a tool for identifying tree seedlings: a proof of concept using a fast technique

Effective identification of plant species is fundamental for a better understanding of natural regeneration. However, classical taxonomic methods largely rely on reproductive structures, which are frequently absent in juvenile individuals. To overcome this difficulty, several approaches may be applied, a good example being external anatomy of the leaf epidermis (hereafter micro-morphology). Therefore, the aim of this paper was to test whether the former cited trait can provide suitable distinctive characters for identification of tree species seedlings in general. We chose six common species from the Southern Brazil Seasonal Forest to proceed with our tests, from which we collected two to four leaves of randomly selected seedlings (five replicates/species). We, then, printed leaf epidermis on a microscope slide with instant adhesive and analyzed for diagnostic features. Our analyses showed that several anatomical characteristics of the leaf surface are distinct enough to allow a correct species identification, such as the shape of the anti-clinal walls of epidermal cells, the shape of stomata, and the presence/absence of glands and cuticle. Hence, the conclusion of this study is that leaf epidermal anatomy can be used as a source of diagnostic characteristics to correctly identify the seedlings of forest species.