Adaptive morphoanatomy and ecophysiology of Billbergia euphemiae, a hemiepiphyte Bromeliaceae

Abstract

Habitats under distinct selective pressures exert adaptative pressures that can lead individuals of the same species to present different life strategies for their survival. The aim of this study was to analyse morphoanatomical and physiological traits for identification of adaptive ecological strategies related to both terrestrial and epiphytic life phases of Billbergia euphemiae. It was verified that B. euphemiae showed lower height, as well smaller length, width and foliar area in epiphytic phase than in terrestrial phase. Concerning to foliar anatomy, the thicknesses of leaf and water-storage parenchyma were higher in terrestrial phase, as densities of stomata and scales on the abaxial surface were higher in epiphytic phase. About the contents of photosynthetic pigments, only chlorophyll a/b ratio showed differences between life phases. In both habits, plants exhibited roots with absorption hair. In epiphytic phase, roots exhibited higher velamen thickness, smaller outer cortex, higher number of inner cortex cell layers and higher number of protoxylem poles. Thus, B. euphemiae individuals in epiphytic exhibited lots of traits related to water retention, once these plants are not into the ground. Besides, the plasticity observed may contribute for survival of this group in habitats submitted to modifications (e.g., climate change and other variations caused by human interference).

Photosynthetic apparatus performance and anatomical modulations of Alcantarea imperialis (Bromeliaceae) exposed to selenium during in vitro growth

“…In this work, the leaf and root anatomy of the plants were in accordance with previous reports of A. imperialis as well as other species of the Bromeliaceae family (Zorger et al 2019, Martins et al 2020a, Silva et al 2020b, Faria et al 2021. Even though Se modulated the root architecture of A. imperialis plants, this metalloid did not interfere with the roots' anatomical traits.…”

Do secondary hemiepiphytes exist?

“…It features long stolons between individual rosettes, and may sometimes climb up a tree trunk in dry resting vegetation, and may or may not sever the connection to the remaining genet. We see the report by Zorger et al (2019) as evidence for facultative epiphytism of an herb with clonal reproduction rather than the first demonstration of "secondary" hemiepiphytism in the family Bromeliaceae. Irrespective of different interpretations in this particular case, such observations highlight that our list of potential candidates is certainly not complete, take, e.g., possibly "hemiepiphytic" Gesneriaceae (Salinas et al 2010) or Begoniaceae (Webster & Rhode 2001).…”

“…Finally, there is also a recent report claiming that a bromeliad, Billbergia euphemiae, is a "secondary" hemiepiphyte (Zorger et al 2019). This species, however, is well-known for its facultative terrestrial, lithophytic and epiphytic growth (Brazilian Flora 2020 in construction continuously updated).…”

Ontogenetic changes in root traits and root‐associated fungal community composition in a heteroblastic epiphytic bromeliad

“…As reported for other species of Bromeliaceae, the presence of root hairs originating from the velamen may be associated with the epiphytic life (Pita and Menezes 2002, Segecin and Scatena 2004, Proença and das Graças Sajo 2008, Silva and Scatena 2011). Presumably, the epivelamen play a role in the plant strategy for water and nutrients absorption and may contribute to the plant mechanical fixation (Segecin and Scatena 2004, Silva and Scatena 2011, Zorger et al 2019). But, in our study we could not evaluate any variation in the density of root hairs along ontogeny because observation of root hairs was not reliable from a transversal section to another one within and between plant stages (Supporting information).…”

“…The velamen is a specific tissue common among monocotyledons (Zotz et al 2017). In the root system of bromeliad species, the velamen is suggested to contribute to the water and nutrient supply, and to the mechanical protection of the root system (Zotz and Winkler 2013, Zorger et al 2019). In several bromeliad species, the more distal part of the velamen (epivelamen) exhibit root hairs, suggesting its role in water and nutrients absorption (Segecin and Scatena 2004, Silva and Scatena 2011).…”