Magnesium is the third most abundant structural metal in the Earth's crust and is found in many rock minerals and in seawater. In the soil, it appears in the ionic form Mg2+, in solution and as an exchangeable cation. After absorption, Mg2+ is transported from the roots to the aerial part through the interior of the plant, giving this process the name of translocation. In plants, magnesium plays a fundamental role for growth and development, participating in a series of important processes for the metabolism of the plant, such as the constitution of the chlorophyll molecule, in addition to acting as an enzymatic activator. Thus, given the importance of the magnesium nutrient, the objective of this review is to present the main aspects of this nutrient in the soil and the functions performed in plants.

Zinc is an element found in low amounts in the soil, which may limit the development of agricultural crops. In addition, the absorption of this nutrient by plants is directly influenced by several factors such as: high pH, ​​amount of organic matter, high humidity associated with low temperatures and soil microbiota. Zinc is important for enzymatic activity, being a constituent part of the enzymes alcohol dehydrogenase, carbonic anhydrase, superoxide dismutase enzyme and polymer RNA, in addition to participating in the synthesis of precursor tryptophan in the metabolism of indoleacetic acid, which is a plant hormone directly related to the development of plants. In plants, the symptoms of zinc deficiency appear with the shortening of the internodes, reduction of the leaf area, reduction of its size, appearance of rosettes, chlorosis and necrosis. Thus, the objective of this review is to present the main aspects of the zinc nutrient in the soil and the functions performed in plants.

Epiphytes are plants that use the mechanical support provided by a host tree, called phorophytes, without emitting haustorial structures. Constituting an important component of the flora, playing an important role in the maintenance of ecosystems, such as water and nutrient cycling, in addition to providing resources, sometimes unique, such as food and shelter, for the canopy fauna. However, the epiphytic flora may show high beta diversity, even when compared with different phorophytes, possibly as a response to the dendromorphological characteristics of the phorophyte. Thus, this work aims to: 1) compare whether the species richness of epiphytes differs in trees with different morphological characteristics, and 2) compare species composition among three tree species. For this, 10 individuals of three tree species were selected: Guaria guidonia, Ficus sp., and Roystonea oleracea. In each individ-

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