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Cadmium (Cd) is a metal known for its genotoxicity and cytotoxicity, much concerned for its potential environmental and human health impacts. This study evaluates the toxic effect of Cd in Calophyllum brasiliense plants. The plants were cultivated for 30 days in full nutrient solution in order to adapt, and for 15 days in nutrient solution without Cd or with 4, 8, 16, and 32 μmol Cd L. Anatomical analysis of the leaf showed no significant effects of Cd on epidermal thickness in abaxial and adaxial sides, palisade, and spongy parenchyma. Contrastingly, changes were noticed in the ultrastructural level in the leaf mesophyll cells as rupture of the membrane of chloroplasts and disorganization of the thylakoid membranes, in starch grains and in mitochondria with rupture of the membrane and invagination of the nuclear membrane. Electron dense materials into cells of the cortex and vascular bundle were also observed. In the cells of the root system, the observed ultrastructural changes were disruption of the cell wall and electron dense material deposition in the cortex cells and vascular region. Cd accumulated in roots with low translocation into shoot. Cd toxicity also affected the photosynthetic activity, inducing stomatal closure and photosynthetic assimilation reduction and the instantaneous carboxylation efficiency, drastically reducing the leaf transpiration. The nutrient content in the stem and root was variable, according to Cd increase in nutrient solution. Based on the experimental evidence, it can be concluded that C. brasiliense has potential to bioconcentrate high Cd levels in the root system.

Pollen abortion occurs in virtually all species and often does not prejudice reproductive success. However, large numbers of abnormal pollen grains are characteristic of some groups. Among them is Miconia, in which partial and complete male sterility is often related to apomixis. In this study, we compared the morphology of pollen grains over several developmental stages in Miconia species with different rates of male sterility. Our aim was to improve the knowledge of mechanisms that lead to male sterility in this ecologically important tropical group. Routine techniques for microscopy were used to examine anthers in several developmental stages collected from the apomictic species Miconia albicans and M. stenostachya. Both species are completely male sterile since even the pollen grains with apparently normal cytoplasm were not able to develop a pollen tube. Meiosis is a rare event in M. albicans anthers and happens in an irregular way in M. stenostachya, leading to the pollen abortion. M. albicans has more severe abnormalities than M. stenostachya since even the microspores and pollen grain walls were affected. Moreover, in M. stenostachya, most mitosis occurring during microgametogenesis was also abnormal, leading to the formation of bicellular pollen grains with two similar cells, in addition to the formation of pollen grains of different sizes. Notably, abnormalities in both species did not reach the production of Übisch bodies, suggesting little or no tapetum involvement in male sterility in these two species.

Environmental cadmium (Cd) sources have increased in mangrove sediments in recent decades, inducing cellular damage to many plants. Avicennia schaueriana is abundant in mangrove sites and has been subject to Cd contamination. The possible effects of Cd toxicity and the structural and physiological disturbances to this plant were studied. Can this plant express early cellular tolerance mechanisms to such metal contamination?• Seedlings of A. schaueriana were collected from sites of their natural occurrence, placed in plastic pots containing nutrient solution for 60 days, and subsequently exposed to increasing Cd concentrations for 5 days under experimental conditions. The anatomical, ultrastructural and physiological changes induced by Cd were analysed.• Cd accumulated mainly in the root system and in pneumatophores, stems and leaves, induced differential accumulation of mineral nutrients, but did not induce necrosis or changes in leaf anatomy. However, there was a decrease in starch grains and an increase in deposited electron-dense material in the cortex and vascular bundles. Cd induced both increases in calcium (Ca) content in shoots and Ca oxalate crystal precipitation in leaf mesophyll and was detected in crystals and in the secretion of salt glands.• Our observations and experimental results provide evidence of Cd tolerance in A. schaueriana. As a new feature, despite the clear cellular physiological disorders, this plant is able to eliminate Cd through leaf salt glands and immobilise it in Ca crystals, representing fast mechanisms for Cd exclusion and complexation in leaves in heavy metal coastal polluted marine ecosystems.

-(Ontogeny and structure of the pericarp and the seed coat of Miconia albicans (Sw.) Triana (Melastomataceae) from "cerrado", Brazil). Miconia albicans fruit and seed coat ontogeny were described under light microscope. The samples were fixed in formalin-aceto-alcohol (FAA), neutral-buffered formaldehyde solution (NBF) and formalin-ferrous sulphate (FFS) solutions, embedded in plastic resin, sectioned at 10 µm and stained with Toluidine Blue. Specific dyes and/or reagents were used for the microchemical tests. The ovary is semi-inferior and the indehiscent, fleshy globose berries are originated mainly from the development of the inferior portion of the ovary. The immature pericarp is mainly parenchymatous with some sclereids, druse crystal and phenolic-like compounds idioblasts widespread in the mesocarp. In the mature pericarp, the endocarp cells are often collapsed, the mesocarp is thick with cells more or less turgid, and the sclereids, the druses and the phenolic-like compound idioblasts are almost absent. The ovules are anatropous, bitegmic and crassinucellate, and the zig-zag micropyle is formed by both the exostome and the endostome. The mature seed is pyramidal-elongated in shape, exalbuminous and testal. The raphal part occupies about 40% of the seed coat total length and had the mechanical layer derived from its inner layer. The antiraphal side is non-multiplicative and the exotesta, mesotesta and endotesta are differentiated into a sclerotic layer, with the exotesta being the mechanical one. The tegmen is absent.Key words -anatomy, fruits, Melastomataceae, Miconia, ontogeny RESUMO -(Ontogenia e estrutura do pericarpo e do envoltório da semente de Miconia albicans (Sw.) Triana (Melastomataceae) do cerrado, Brasil). A ontogenia dos frutos e das sementes de M. albicans foi descrita sob microscopia de luz. Os materiais foram fixados em soluções de formalina -ácido acético -álcool etílico 50% (FAA), formalina neutra tamponada (FNT) e sulfato ferroso em formalina (SFF), embebidos em resina plástica, seccionados a 10 µm de espessura e corados com Azul de Toluidina. Corantes e/ou reagentes específicos foram usados para os testes microquímicos. O ovário é semi-ínfero, e os frutos são bagas indeiscentes, originadas em sua maior parte a partir do desenvolvimento da porção ínfera do ovário. O pericarpo imaturo é principalmente parenquimático, com esclereídes, idioblastos cristalíferos e com compostos fenólicos no mesocarpo. No pericarpo maduro as células do endocarpo estão freqüentemente colapsadas, o mesocarpo é espesso, com células túrgidas, e as esclereídes e os idioblastos cristalíferos e com compostos fenólicos estão em pequena quantidade. Os óvulos são anátropos, bitegumentados e crassinucelados, e a micrópica, em zig-zag, é formada pelo exóstoma e pelo endóstoma. A semente madura é piramidal-alongada, exalbuminosa e testal. A porção rafeal ocupa aproximadamente 40% do comprimento total da semente e possui a camada mecânica derivada de suas camadas internas. A porção anti-rafeal é não-multiplicativ...