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In order to better understand the physiological and technical aspects of yerba mate vegetative propagation, the present study sought to evaluate the rhizogenic capacity of apical and basal mini-cuttings from different genotypes (named A3, A7, F1 and F2) and the possible relationships between rooting and specific biochemical and anatomical aspects of the species. After 90 days under greenhouse conditions, the following variables were assessed: mini-cuttings rooting percentage, number of roots, roots length, callogenesis, mortality, sprouting and leaf retention. Mini-cuttings samples were collected at the time of planting and after 90 days in the rooting environment in order to investigate the aspects related to stem and roots anatomy as well as the levels of phenolic compounds (PC) and the activities of peroxidade (POD) and polyphenol oxidase (PPO) enzymes. Genotype A3 presented the best rooting performance (65.6% rooting) while F2 had the lower rooting rates (24.5%). Apical and basal mini-cuttings did not differ regarding rooting associated variables. Both mini-cuttings types and the four genotypes showed identical anatomical features, with no evident mechanical barriers to roots emission. Despite specific differences on POD, PPO and PC activities/contents as influenced by topophysis, genotype and/or their interaction, no direct relationship could be stated between the biochemical features at the time of planting or 90 days after and the overall rooting performance of yerba mate the mini-cuttings. The present study not only provides valuable information on technical aspects of yerba mate propagation but also presents insights in the physiological and anatomical traits of adventitious rhizogenesis in this species.

Toward improving reforestation of Brazilian pine (Araucaria angustifolia), two contrasting sapling sizes in either full sun or in the shade of a mixed plantation and the effect of opening the canopy were evaluated for survival, growth, gas exchange, photosynthetic pigments, and leaf anatomy 18 months after being planted. At 23 months after planting, a partial opening was made in the canopy in the mixed plantation, then the saplings were evaluated again after 2 months for the same morphophysiological traits. After 18 months, saplings planted in the full sun had higher survival, growth, pigments, and photosynthesis compared to the shaded saplings. Large saplings had higher survival and growth compared to the small ones. Shaded leaves were thinner and little differentiation of palisade parenchyma and hypodermis. After opening of the canopy, photosynthetically active radiation was 10 times higher, and the saplings quickly grew in height due to increased photosynthesis. Thus, although the species can tolerate shade, growth in the shade is limited. We recommend that for reforestation purposes of Brazilian pine, large saplings should be selected and planted in the open for better development.

Butia buenopolensis, a new dwarf Arecaceae species, is described. Butia buenopolensis occurs in the Serra do Cabral mountain range in Buenopolis municipatility, Minas Gerais, Brazil. Despite its diminutive size, it has arched yellowish-green leaves and pinnae not as narrow as the species of the grass-like Butia. The new species is closely related to B. archeri, based on morphology, phenology (flowering time) and habitat. They differ in leaf anatomy, plant size, color and size of inflorescence. Some novelties in Butia flower morphology, such as striated cuticle of anthers, functional staminodes presenting evidence of secretory activity, raphides on the petals of pistillate flowers and the cappilinection adhesion of petal margins, were introduced here and suggested as a new approach for future taxonomical and evolutionary studies of this genus. The isolated and small groups of fibers in the mesophyll and a non-vascular fiber bundle connected to the adaxial epidermis in the leaf midrib have not been found in any other Butia so far. The one population recorded for the new species is restricted to an area near the limits of Serra do Cabral State Park, clearly vulnerable to different forms of anthropic pressure. So, it is strongly recommended an extension in area of Serra do Cabral State Park to include the B. buenopolensis range of occurrence within its borders.

The formation of an oleaginous palm fruit was described by anatomical and physiological evaluations that allowed us to correlate and associate pericarp and seed ontogenesis and define the developmental phases. The pseudomonomerous pyrenarium fruits of Arecaceae demonstrate complex and slow development pathways, and accumulate large quantities of energy reserves, making them of economic interest. Very little is known about the association between pericarp and seed development in this family. We characterize here the ontogenesis of Acrocomia aculeata fruits, a neotropical oleaginous palm, define their developmental phases, investigate the relationship between embryogenesis and fruit development, and describe the formation of structures related to dormancy and reserve accumulation. The development of the pistillate flowers and fruit structures were accompanied over time and evaluated biometrically, anatomically, and through histochemical tests. Bromatological evaluations were performed on the mesocarp and seeds during their reserve accumulation phases. A. aculeata flowers are tricarpellate and syncarpous, although normally only a single ovule develops; the other ovules degenerate and become incorporated into the pyrene. The seed is pachychalazal and embryogenesis is precocious in relation to fruit development. The exocarp is the first pericarp structure to attain maturity, while the pyrene undergoes significant lignification, except for the region near the abscission zone and acquires a petrous consistency. The development of the endocarp is restricted to the germination pore plate and seed operculum, and is associated with dormancy restrictions. The accumulation of lipids in the mesocarp occurs near the time of abscission. A. aculeata fruits require approximately one year for full development, which occurs in three phases: the histo-differentiation of the pericarp; seed maturation; and mesocarp maturation.

Acrocomia aculeata is an oleaginous palm widely distributed through the tropical and subtropical Americas that shows significant potential for agroindustrial use. Studies of floral structures can contribute to our knowledge of the evolutionary diversification of this genus and ecological aspects of its species as well as assist management and domestication programs. With the objective of characterizing the morphoanatomy of the flowers of A. aculeata, 20 inflorescences were collected in each of three natural populations growing in the northern region of Minas Gerais State, Brazil. Flowers at anthesis were evaluated biometrically and using standard plant anatomical procedures, and observed under light and scanning electron microscopy. The flowers showed wide biometric variability that was influenced by the collection area, the individuals examined, and the positions of the flowers on the inflorescence. Staminate flowers can have two whorls of petals, small anthers, and vestigial structures, with the development of an infertile carpel and rudimentary ovules. Defenses against herbivory include the presence of raphides in the anthers and pistillate flowers, fiber bundles, stegmata, and idioblasts containing phenols and raphides. Pollinators are attracted by the liberation of intense odors produced by osmophores located in the corolla, with pollen being the principal resource offered. Phenotypic plasticity, the structures involved in defending against herbivores and attracting pollinators, the numbers of flowers, and flowering synchrony contribute to the reproductive success of this species. The short period during which the stigmas remain receptive determines synchronous fertilization within the inflorescence.

Butia capitata, an endemic palm of the Brazilian savanna threatened by deforestation, demonstrates low germinability due to seed dormancy. The present study characterizes the structure of the zygotic embryo and describes germination and seedling development. Pyrenes were sown into sandy soil substrates to germinate, and their embryos were also cultivated in vitro in MS medium; structural evaluations were made during their development. Seedling growth through the endocarp germ pore culminates in the protrusion of the cotyledonary petiole, with the root and leaf sheaths subsequently being emitted laterally from its extremity. The embryos are composed of the cotyledon (whose proximal third has a haustorial function) and a diminutive embryo axis that is contained within the cotyledonary petiole. The protoderm, ground meristem, and procambium can be observed in their typical positions in the embryo axis and cotyledon. The development of the vegetative axis could be observed on the second day of in vitro cultivation, with elongation of the embryo axis and the beginning of the differentiation of the first eophyll. Elongation of the cotyledonary petiole and the differentiation of the parenchyma and tracheary elements were observed during the second to fifth day. Although the hypocotyl–radicle axis is less differentiated than the plumule, root protrusion occurs on the eighth day, and the leaf sheaths are only emitted between the twelfth and the sixteenth days; the haustorium atrophied during this stage. The embryonic structure of B. capitata does not impose limitations on seed germination as dormancy is of the non-profound physiological type, and the 50 % elongation of the cotyledonary petiole serves as a morphological indicator of germination.

Fluoride is among the most phytotoxic atmo- spheric pollutants, commonly linked to the appearance of lesions in susceptible plants around emitting sources. In order to assess the effects of fluoride on leaves of Spondias dulcisParkinson (Anacardiaceae), plants were examined 78 km (non-polluted area) and 0.78 km (pol- luted area) from an aluminium smelter. The level of fluoride increased with the exposure time of the plants in the polluted area. On the third day of exposure in the polluted area, necroses with typical colouration were observed. Micromorphological damage began at the abaxial epidermis, mainly associated with the stomata. Starch grain accumulation was more pronounced in the midrib. The cell membranes and chloroplasts were greatly affected by the pollutant. We observed accumu- lation of phenolic compounds and electron-dense mate- rial at the boundaries of the ending veinlets. The micro- scopic events described precede the appearance of symptoms and are therefore of prognostic value in predicting injury by fluoride and will be useful as biomarkers. The high sensitivity of S. dulcis to fluoride and the specificity of the symptoms confirm, for the first time, in an experiment of active biomonitoring, the potential of this species as a bioindicator.