Plants in the caatinga possess multiple adaptative leaf morphoanatomical traits concurrently, a pattern revealed from a systematic review

Abstract

Plants in seasonally dry forests, such as the Caatinga in Brazil, possess adaptive characteristics to endure prolonged periods of drought and intense sunlight. However, few studies have delved into understanding, as proposed here, the convergence of these traits based on morphoanatomical features. Therefore, based on a systematic review, we investigated the morphoanatomical traits of Caatinga plant's leaves in terms of their occurrence and frequency among species, as well as their combinations. This review encompasses data from 69 species distributed across 24 botanical families, with 13 species exclusive to the Caatinga. Through this review, we present the most common morphoanatomical leaf traits of Caatinga plants, discussing their functional significance in dry forests. Traits such as uniseriate epidermis, tector trichomes, amphistomatia, dorsiventral mesophyll and crystals were the most prevalent. Additionally, traits not typically described as advantageous for semi-arid regions, such as stomata at the same level and/or above common epidermal cells, were identified. Our review unveils the significant sharing of morphoanatomical leaf characteristics among Caatinga plants, with the observation of three clusters associated with these traits, composed of subshrub, shrub, arboreal and/or herbaceous species. The shared traits underscore the evolutionary association between traits and the environment. Finally, this comprehensive overview of these traits allows us to understand the dynamics of Caatinga plants and serves as a foundation for future analyses of the varying vulnerability of plants within each cluster to climate change.