Changes in bioaccumulation and translocation patterns between root and leafs of Avicennia schaueriana as adaptive response to different levels of metals in mangrove system.

Espírito Santo estuaries (Brazil) are impacted by industrial activities, resulting in contamination of water and sediments. This raise questions on biological uptake, storage and consequences of metal contamination to mangrove plants. The goal of this work was evaluating accumulation and translocation of metals from sediment to roots and leaves of Avicennia schaueriana, growing in areas with different degrees of contamination, correlating bioaccumulation with changes in its root anatomy. Highest bioconcentration factors (BCFs) were observed in plants growing in less polluted areas. Conversely, highest translocation factors were found in plants from highest polluted area, evidencing an adaptive response of A. schaueriana to less favourable conditions. Namely, the absorption of metals by roots is diminished when facing highest levels of metals in the environment; alternatively, plants seem to enhance the translocation to diminish the concentration of toxic metals in roots. Root also responded to highly polluted scenarios with modifications of its anatomy.

Matching metal pollution with bioavailability, bioaccumulation and biomarkers response in fish (Centropomus parallelus) resident in neotropical estuaries.

Two neotropical estuaries affected by different anthropogenic factors were studied. We report levels of metals and metalloids in water and sediment as well as their influence on genetic, biochemical and morphological biomarkers in the native fish Centropomus parallelus. Biomarkers reflected the fish health status. Multivariate statistics indicated both spatial and temporal changes in both water and sediment, which are linked to the elemental composition and health status of inhabitant fish, showing the biggest influence of surface water, followed by sediments and interstitial water. Bioaccumulation in fish muscle was useful to identify elements that were below detection limits in water, pointing out the risk of consuming fish exceeding allowance limits for some elements (As and Hg in this case). Multivariate statistics, including physical, chemical and biological issues, presents a suitable tool, integrating data from different origin allocated in the same estuary, which could be useful for future studies on estuarine systems.

Leaf emergences in Microlepis oleaefolia (DC.) Triana (Melastomataceae) and their probable function: an anatomical and ultrastructural study.

Microlepis oleaefolia (DC.) Triana, an endemic species of Melastomataceae from the Brazilian cerrado, presents very complex leaf structures called as "hairs with root-like base" embedded in the mesophyll. This paper describes the ontogenesis, histochemical and structural aspects of these leaf structures as a framework for further functional studies. Samples of leaves in different developmental stages were processed according to common light and electron microscopy techniques. Fresh material was subjected to histochemical tests to examine the chemical composition of cell walls. The apoplastic transport between leaf emergences and the vascular system was verified by staining with 1% aqueous safranin. The structures are emergences of mixed protoderm and ground meristem origin. They are persistent, predominantly short-stalked and dendritic. Their arms have thick non-lignified cellulosic walls with a loose and heterogeneous aspect; on the inner face, the wall, which appears labyrinthine, presents small irregularly shaped projections directed towards the protoplast. The base of the emergences is composed of sclereids embedded in the mesophyll that reach the vascular system. Assays with aqueous safranin solution revealed it penetrates the cell walls of the arms and showed a connection between the emergence and xylem. Anatomical, chemical and ultrastructural features of leaf emergences of M. oleaefolia indicate that these structures are able to transport substances via apoplast and can absorb or exude solutions.