Functional groups in Lychnophorinae (Asteraceae: Vernonieae) based on morphological and anatomical traits

Abstract

The Lychnophorinae subtribe (Asteraceae: Vernonieae) occurs mainly on the Central Brazilian Plateau, especially in areas characterised by intense solar radiation, large daily temperature fluctuations, water scarcity during autumn and winter, and frequent fire. However, a few species of Lychnophorinae, such as Blanchetia heterotricha DC., are not restricted to the Cerrado Domain, but can live in open and humid areas of borders of the Atlantic Forest. To understand the mechanisms of Lychnophorinae adaptation to these environmental conditions, habit, leaf and stem functional traits from 12 species were analysed. Leaf and stem samples were processed and stained using standard plant-anatomy methodology. A comparative analysis of functional groups was performed by principal coordinates analysis, which was applied to two matrices of 30 qualitative and five quantitative traits. The multivariate analysis based on qualitative traits highlighted the following four functional types that might be linked to ecological conditions: Group I adapted at open and humid areas of borders of the Atlantic Forest; Group II, with features mostly related to foggy habitats; Group III, exhibiting traits quite adapted to the seasonally dry and variable conditions of the campos rupestres; and Group IV, showing the most specialised morphological and anatomical traits, which might be related to the extreme conditions of the campos rupestres

Ecology and evolution of plant diversity in the endangered campo rupestre: a neglected conservation priority

“…Because plants from campo rupestre usually show traits related to greater resource conservation ) compared with those in lowland close relatives in the Atlantic rainforest and cerrado (Lusa et al 2014), many plant traits in the campo rupestre are thought to be adaptations to cope with high irradiance, strong winds, and the seasonal distribution of rainfall. All these filters combine with the nutrient-impoverished shallow soils with a low water-holding capacity that leads to long periods of severe water limitation for plant productivity (Lüttge et al 2007;Morales et al 2014Morales et al , 2015Miola and Fernandes 2015).…”

“…Lusa et al 2014), and these structures may play a role in atmospheric water uptake (Martin and von Willert 2000). White trichomes are also common and, together with shortened internodes, they reduce the fraction of radiation that is absorbed by leaves in a wide range of phylogeneticallyunrelated species (e.g., Lusa et al 2014).…”

Five new species of Vernonieae (Asteraceae) from Espírito Santo, Brazil

“…These environmental filters confers highly specialized flora to this habitat (Larson 2000;Porembski 2007). Cololobus argenteus is categorized as endangered (EN) according to the criteria B1ab (i, iii) + 2ab (ii, iii) of IUCN (2016) Cololobus argenteus has very dense greyish and silvery trichomes on branches and leaves and many imbricated leaves, which may be associated to reduction on leaf transpiration and foliar water uptake (Eller et al 2013(Eller et al , 2016Givnish et al 1986;Lusa et al 2014;Werker 2000), protection against excessive light and extreme temperatures (Lusa et al 2014;Werker 2000), and fire (Clarke et al 2013;Givnish 1986;Lusa et al 2014). Additionally, wide, long and flexible inflorescences and pappus with bristles may be related to wind dispersal of fruits (Jeffrey 2009).…”

A Phylogenetic Analysis of Lychnophorinae (Asteraceae: Vernonieae) Based on Molecular and Morphological Data

“…This hypothesis has been previously suggested by Semir (1991) and is supported by some anatomical evidence based on the disposition of leaf trace (Luque and Menezes 2003). Leaf sheaths may strengthen the adaptive ability of the species to drought-tolerance (Lusa et al 2014).…”