Wood functional anatomy of Chiococca alba Hitch. (Rubiaceae) from cerrado

Abstract

The wood anatomy is able to evidence systematic and ecological aspects associated with the evolution and functionality of the secondary xylem. The present study was carried out using wood of Chiococca alba (Rubiaceae) from cerrado (savannah), to describe its anatomy and to verify if the hydraulic architecture of this species corroborates the theory that postulates the functional tendency that optimizes the transport efficiency associated with safety. The anatomical analysis followed the conventional protocols of wood anatomy. Different indexes of wood hydraulics quantification were calculated, such as solitary vessels index, vessel grouping, conductivity, vessel collapse, theoretical resistance to vessel implosion and mesomorphism. The structural characteristics described for C. alba are in agreement with the general anatomical descriptions for the Rubiaceae family that relate the presence of exclusively solitary vessels and small diameter, simple perforation plates, alternate intervessel pits, apotracheal parenchyma in species with non-septate fibers and narrow and heterogeneous rays. The calculated indexes showed that C. alba is a xerophyte species with great resistance to the collapse of the vessels during the transport of water, little vulnerability to embolism and relative efficiency in the transport when compared to other species of its subfamily (Cinchonoideae) in function of the typical low water availability of the savannah soil.

Functional anatomy and xylem cavitation resistance of three species of monocotyledons grown on flooded substrates

“…Apparently, no other studies have been performed on the RC in herbaceous plants, as this model was developed for woody plants. However, the values recorded in C. indica , C. papyrus and P. communis , are similar to those recorded in woody plants (Reyes‐Santamaría et al , Gutiérrez et al , Melo‐Júnior et al ). These results indicate that when considering only the radius and the number of vessels per unit area, the conductive system of herbaceous and woody plants shows a similar capacity to conduct water.…”

Functional traits and water‐transport strategies of woody species in an insular environment in a tropical forest

“…In contrast, the greater variability of the traits in T. guianensis in different phytophysiognomies may reflect conductive efficiency in DOF and embolism resistance in RES. Larger diameters of vessel elements accompanied by lower frequencies represent greater transport efficiency (Melo Júnior et al, 2017), whereas P 50 is related to resistance to embolism (Pereira et al, 2018). Most individuals of E. pulchrum from restinga are grouped in the quadrant close to individuals of T. guianensis from the same phytophysiognomy, suggesting that traits related to safety in transportation in environments with water restriction can act synergistically between both species, even with low intraspecific variation.…”

“…Regarding leaf traits, we expected to find smaller leaf area with greater stomatal density and lower stomatal conductance. For wood traits, we expected to find a greater frequency of vessels with smaller diameters and thicker walls, greater wood density, greater thickness of the intervascular pit membrane and greater resistance to embolism ( P 50 ), since the species growing in the restinga can be exposed to high temperature and greater water deficit compared to the species that occur in the dense ombrophilous forest (Melo Júnior et al, 2017; Dória et al, 2018; Pireda et al, 2019).…”