Wood anatomy of Laguncularia racemosa (Combretaceae) in mangrove and transitional forest, Southern Brazil

Abstract

Mangroves represent an environment of great heterogeneity and low diversity of plant species that have structural and physiological adaptations linked to a high salinity environment. Laguncularia racemosa is a typical tree species in mangroves and transitional zones. This study aimed to compare the wood anatomy of L. racemosa (Combretaceae) in two different forests (mangroves and transitional forests), which have different soil conditions. For this, we obtained wood and soil samples in March 2016. We analyzed soil nutritional contents in one 15 cm deep soil sample per forest type. In addition, we selected five mangrove trees in each formation for wood anatomy analysis and took one wood sample per individual, per area. We prepared histological slides and separated materials following standard methods for wood anatomy studies. Soil analysis showed that mangrove soils had higher phosphorus, potassium and calcium contents. The transitional soil had lower pore water salinity and soil pH, probably due to high aluminum levels. Anatomical attributes differed between different forest populations. In the different wood aspects evaluated, we obtained higher values in mangrove individuals when compared to the transitional forest population: vessel elements length (375.79 mm), tangential vessels diameter (75.85 mm), frequency of vessels (11.90 mm) and fiber length (889.89 mm). Moreover, parenchyma rays height was larger in the samples of the transitional forest (392.80 mm), while the mangrove population presented wider rays (29.38 mm). The structure of the secondary xylem in the studied species apparently responds to edaphic parameters and shows variations that allow it to adjust to the environmental conditions. The population of the transitional forest showed a secondary xylem that invests more in protection than the mangrove population. Rev. Biol. Trop. 66(2): 647-657. Epub 2018 June 01.

Laguncularia racemosa leaves indicate the presence of potentially toxic elements in mangroves

“…This result may be directly related to the saline conditions in which the species lives, suggesting that the leaves could contribute to the water support capacity. Such support would be fundamental for mangrove species subjected to constant physiological drought, similar to that proposed for parenchyma rays in L. racemosa wood 53 .…”

Contrasting Water Use, Stomatal Regulation, Embolism Resistance, and Drought Responses of Two Co-Occurring Mangroves

“…While these interspecific differences are associated with differences in salt management strategy, other factors are also likely to influence the physiology of these species during drought. For example, A. marina shows greater xylem cavitation resistance, which may be due to xylem plasticity because mangrove vessels can become narrower as salinity increases [13,84]. Similarly, mangroves are thought to have traits associated with high embolism resistance, such as higher vessel density, higher vessel grouping index [85], smaller vessel diameter, and successive and simultaneous cambia [86], all of which may be plastic (e.g., vary in response to salinity) and could change ontogenetically.…”

Combretaceous fossil wood from Ituzaingó Formation (Late Miocene?), Argentina, indicate a coastal marine environment

“…Journal Pre-proof 2011) and descriptions by Metcalfe and Chalk (1950), van Vliet (1978van Vliet ( , 1979, Silva and Espinoza (1995), León (2001), andJantsch et al (2018) were consulted.…”