Leaf anatomical traits of non-arboreal savanna species along a gradient of tree encroachment

Abstract

In the Brazilian savanna (Cerrado of Brazil), fi re suppression has transformed typical savanna formations (TS) into forested savanna (FS) due to the phenomenon of encroachment. Under encroachment, non-arboreal plants begin to receive less light due to greater tree density and canopy closure. Here we aim to evaluate if leaf anatomical traits of non-arboreal species diff er according to the degree of tree encroachment at the Assis Ecological Station -São Paulo, Brazil. To this end, we evaluated leaf tissue thickness and specifi c leaf area (SLA) in representative non-arboreal species occurring along a gradient of tree encroachment. Leaves of TS species showed a trend towards xeromorphism, with traits reported to facilitate survival under high luminosity, such as thick leaves, thick epidermis and mesophyll, and low SLA. In contrast, FS species exhibited mesomorphic leaves, with thin mesophyll and high SLA, which are able to capture diff use light in denser environments. Th us, non-arboreal understory species with mesomorphic leaf traits should be favored in environments with denser vegetation in contrast to typical savanna species. Th e results suggest that typical non-arboreal savanna species would not survive under tree encroachment due to the low competitiveness of their leaf anatomical strategies in shady environments.

Photosynthetic responses of understory savanna plants: Implications for plant persistence in savannas under tree encroachment

“…The lower SLA and high carotenoid concentration of TS species can be posed as an indicator of protection mechanisms against the elevated irradiances prevailing on these more open savanna habitats (Franco and Lüttge, 2002;Franco et al, 2007). The lower values of SLA of TS species is the result of high level of investment in tissue thickness, closely packed mesophyll cells and in suberized and lignified structures (Bieras and Sajo, 2009;Pinheiro et al, 2017). In contrast, understory FS plants showed thinner leaves with high concentrations of chlorophyll b on a leaf area basis.…”

Influence of environment on the leaf morpho-anatomy and histochemical of the ayahuasca leaf: Populations cultivated in extra-Amazonian regions

“…Studies of internal and external Psychotria morphology have shown great anatomical and morphological variation (Davis, Bridson, Jarvis, & Govaerts, 2001;Quinteiro, Teixeira, Moraes, & Silva, 2007;Moraes, Rabelo, Alexandrino, Silva Neto, & Cunha, 2011;Nery, Ribas, & Koehler, 2014;Pinheiro, Kolb, & Rossatto, 2018), which makes it difficult to establish determinative morphological structures for the group taxonomy. Domatia was considered determinant for the taxonomy of P. viridis in Atlantic Forest (Quinteiro et al, 2007).…”

Shade drives plant community changes of ground‐layer savanna vegetation: Short‐term changes under an experimental approach

“…Our results indicate that subshrubs and, especially, shrubs seem to be a little more persistent when shading is experimentally imposed. Phenotypic plasticity may contribute to some degree of persistence in the case of species that occur under both closed‐canopy vegetation and encroaching savanna conditions (Pinheiro et al, 2018). Shrub cover increased at T1 in shaded treatments, which may reflect the production of leaves with larger surfaces as a response to low light levels (Valladares & Niinemets, 2008).…”