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O gênero Tibouchina apresenta aproximadamente 350 espécies, dentre elas, Tibouchina affinis fothergillae, Tibouchina heteromalla, Tibouchina moricandiana var. vinaceae e Tibouchina sellowiana. Por se tratarem de espécies nativas do Brasil, podem ser utilizadas para revegetação de áreas antropizadas, devido à característica pioneira. A presente pesquisa objetivou estudar a propagação vegetativa via miniestaquia, utilizando ácido indol butírico (AIB) e ácido fúlvico (AF), bem como realizar determinações bioquímicas e quantificar a produtividade de minicepas destas espécies. Os propágulos foram coletados de um minijardim clonal, nos meses de abril, junho, setembro e novembro/2017, confeccionados com 5+1 cm de comprimento, corte em bisel na base e reto no ápice, mantendo-se um par de folhas reduzidas à metade. As bases das miniestacas foram submetidas aos tratamentos: 0 mg L-1AIB/AF, 2000 mg L-1AIB, 2000 mg L-1AF e 2000 mg L-1AIB+AF. O experimento foi instalado utilizando-se tubetes de 53 cm³ com vermiculita, avaliados após 33 dias de permanência em casa de vegetação, considerando-se a porcentagem de enraizamento das miniestacas. O delineamento foi inteiramente casualizado, num esquema fatorial de 4x4 (quatro épocas de coleta x quatro tratamentos), conduzido individualmente/espécie. As espécies não responderam aos tratamentos com AIB/AF. Nas diferentes épocas de coleta dos propágulos, o enraizamento foi superior a 95% para todas as espécies em abril, setembro e novembro, exceto para Tibouchina sellowiana com 49% de enraizamento no mês de novembro, demonstrando o efeito direto das condições ambientais as quais as plantas matrizes estavam sujeitas, sob a rizogênese. Conclui-se que não há necessidade da aplicação de AIB/AF para a propagação vegetativa das diferentes espécies de Tibouchina, sendo viável o uso da técnica de miniestaquia. Visando a maior produtividade de miniestacas, recomenda-se coletar os propágulos em abril para Tibouchina affinis fothergillae e Tibouchina moricandiana var. vinaceae, em novembro para Tibouchina heteromalla e em junho para Tibouchina sellowiana.

To improve the production process of Aegiphila brachiata cuttings, the objective of this study was to evaluate the rhizogenic potential of cuttings from rejuvenated and adult mother plants collected in different seasons; we also characterized anatomically the cutting base, analyzed phenolic compounds and proteins contents, and identified polar metabolites. Two rooting experiments were carried out with cuttings from rejuvenated and adult mother plants, both collected in the four seasons of the year, submitted to treatments with indole butyric acid (0, 2000, 4000, 6000, and 8000 mg L− 1 IBA), and kept in a greenhouse for 45 days. The experimental design was completely randomized in a double factorial scheme for cutting experiments (5 [IBA] x 4 seasons), and for biochemical analyses (2 mother plants x 4 seasons, material collected in the moment of rooting experiment installation and after 45 days); for metabolomic characterization, the 2 mother plants were evaluated only at summer experiment installation. Propagules from rejuvenated mother plants collected in the spring are more viable and indicated to produce A. brachiata cuttings (25.25% rooting), not requiring the use of IBA. Despite the higher rooting rate of cuttings from rejuvenated mother plants, there are no anatomical differences from adult mother plants cuttings. The highest contents ​​of phenolic compounds were observed in propagules from rejuvenated mother plants in spring, indicating a positive effect of these compounds on the rhizogenic process. Maleic acid, 2-hydroxy-glutaric acid, mannose-6-phosphate, ribonic acid, glycine, and phosphoric acid were found in higher concentrations in cuttings from rejuvenated mother plants, with possible beneficial physiological effects on cuttings rooting.

Common Bean (Phaseolus vulgaris) is considered one of the most affordable sources to tackle hunger in underdeveloped countries. However, its cultivation takes place in regions that suffer from water deficiency, which limits plant growth and crop yield. Therefore, it is necessary to seek sustainable alternatives that mitigate the deleterious effects of water shortage. The aim of this study was to evaluate the potential for mitigating the effects of water deficit with the application of the microalgae Asterarcys quadricellulare (CCAP 294/1) in two bean cultivars (IAC 1850 and BRS ESTEIO). The plants were grown in pots, with foliar application of microalgae at stage of third fully expanded trefoil at concentrations of 0.5 mL L− 1 and 1.0 mL L− 1. The water deficit lasted for 7 days, and, after that, the rehydration of the plants was performed. Evaluations were carried out in three periods: i. on the third day after the start of water restriction, ii. one day after rehydration, iii. 10 days after rehydration. The levels of chlorophyll, sugars, protein and antioxidant enzymes were increased in plants treated with microalgae. At ten days after rehydration, there was an increase in leaf area, fresh mass, and leaf thickness in the treated plants. Our results demonstrate the effects of A. quadricellulare (CCAP 294/1) in mitigating the deleterious effects of water deficit, accelerating the recovery of the two common bean cultivars, which demonstrates its potential as a sustainable alternative to support food production under changing environment.

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.

The Syagrus glaucescens complex comprises three species: Syagrus glaucescens Glaz. ex Becc., Syagrus duartei Glassman, and Syagrus evansiana Noblick. Recently, a new population of S. evansiana that possesses a high degree of endemism was reported in the Serra do Cabral mountain. Here we intend to study the leaf anatomy of the S. glaucescens complex and confirm whether this newly found population (from now on called Syagrus aff. evansiana) belongs to S. evansiana or not. Specimens were collected to investigate their leaf anatomy, which showed distinct differences between S. aff. evansiana and S. evansiana. The midrib anatomy revealed novelties for the S. glauscecens complex, proving useful for species diagnosis. Features such as accessory vascular bundles around the vascular system of the midrib and the number of collateral bundles are diagnostic for species identification. In addition, morphological and anatomical analyses indicated a correlation with the species occurrence. We found greater similarity between S. glaucescens and S. duartei, while S. evansiana and S. aff. evansiana are more alike. Here, we propose a new identification key based only on the leaf anatomy. Despite their morphological similarities, S. aff. evansiana and S. evansiana presented differences in leaf anatomy, which — when associated with their geographical isolation — suggests a fourth taxon in the complex.

Cowpea (Vigna unguiculata) plays a strategic role in arid and semi-arid regions being used in both human food and animal supplementation. Although it is described as moderately tolerant plant to soil salinity, little is known about the salinity tolerance amongst different cultivars and phenological phases. In this study, we investigated the response of seed germination and seedling establishment of V. unguiculata cv. BRS Imponente under conditions of both salt (NaCl) and osmotic stress (Polyethylene glycol 6000; PEG). Although such conditions lead to an accumulation of hydrogen peroxide (H2O2), oxidative damage was observed only in seeds exposed to PEG. The maintenance of H2O2 concentrations in seeds exposed to NaCl, as well as the increase in respiratory activity, were the main mechanisms of tolerance identified in seeds exposed to NaCl. However, although germination was not affected, NaCl concentrations ≥75 mM were phytotoxic, reducing seedling growth. The osmotic component of salinity (PEG) reduced germination (Ѱo

Eugenia uniflorais aspecies that presents great phytochemical variability, due to its main form of propagation, the seminal,which makes the cultivation of this commercial crop unfeasible. Therefore, the objective of this work was to develop a protocol for vegetative propagation of Eugenia unifloraby stem cuttings. Substrates (Tropstrato®, vermiculite and sand), indolbutyric acid concentrations, rejuvenation methods (drastic pruning and minicutting) and harvesting times (winter, summer, autumn and winter) of the stems were compared. The highest rooting percentage and quality of the root system in cuttings were obtained when commercial substrate Tropstrato® and with some method of rejuvenation were used. The minicutting was more efficient, reaching almost 50% of rooting when collected in summer . Stem cuttings from plants that did not undergo any kind of rejuvenation, regardless of the time of collection, did not result in root formation. No anatomical changes were observed between cuttings from rejuvenated and non-rejuvenated plant material, indicating that the rhizogenic process did not occur in the cuttings originated from plants without rejuvenation because of biochemical and/or physiological reasons.The treatment of the stem cuttings with IBA did not result in increase of rooting, therefore the use of this plant regulator is not recommended., Eugenia uniflora é uma espécie que apresenta grande variabilidade fitoquímica, devido à sua principal forma de propagação, a seminal, o que inviabiliza o cultivo dessa cultura comercialmente. Portanto, o objetivo deste trabalho foi desenvolver um protocolo para propagação vegetativa de Eugenia uniflora por estaquia. Substratos (Tropstrato®, vermiculita e areia), concentrações de ácido indolbutírico, métodos de rejuvenescimento (poda drástica e miniestaquia) e épocas de colheita (inverno, verão, outono e inverno) das estacas foram comparados. A maior porcentagem de enraizamento e qualidade do sistema radicular em estacas foram obtidas com o substrato comercial Tropstrato® e com algum método de rejuvenescimento. A miniestaquia foi mais eficiente, chegando a quase 50% do enraizamento quando coletada no verão. Estacas caulinares de plantas que não sofreram nenhum tipo de rejuvenescimento, independente da época de coleta, não resultaram na formação de raízes. Não foram observadas alterações anatômicas entre estacas oriundas de material vegetal rejuvenescido e não rejuvenescido, indicando que o processo rizogênico não ocorreu nas estacas oriundas de plantas sem rejuvenescimento por motivos bioquímicos e / ou fisiológicos. O tratamento das estacas caulinares com AIB não resultou em aumento do enraizamento, portanto o uso deste fitorregulador não é recomendado.

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.

Variation in environmental conditions, such as light availability, can affect herbicide efficacy by altering leaf morphoanatomy. Accordingly, the aim of the present study was to evaluate the influence of light level and herbicide application on leaf anatomy and herbicide efficacy, using Macroptilium atropurpureum as a model weed species. The experiment involved a factorial design (3 × 4), using three light levels (0, 50, or 70% shadow) and four herbicide treatments (no herbicide, glyphosate, carfentrazone-ethyl, or a combination of glyphosate and carfentrazone-ethyl). When combined, the herbicides were efficient in controlling M. atropurpureum under all light levels. However, when applied independently, the herbicides failed to satisfactorily control plants cultivated in full sunlight, and plants cultivated in shaded environments were more sensitive to glyphosate application than those cultivated in full sunlight. The greater efficacy of the herbicides on plants grown under shaded conditions can likely be attributed to changes in leaf morphoanatomy. Plants grown under restricted light conditions exhibit greater average leaf area, lower trichome density, reduced epicuticular wax deposition, thinner leaves, and lower dry mass accumulation, characteristics which are closely correlated to chemical control. The combination of the herbicides presents an additional effect in the control of M. atropurpureum. Also, changes in leaf anatomy caused by light restriction reduce the tolerance of M. atropurpureum to the herbicides.

The co-occurrence of aquatic contaminants, such as antibiotics and herbicides, has motivated investigations into their interactive effects on aquatic organisms. We examined the combined effects of environmental concentrations of the antibiotic Enrofloxacin (Enro; 0–2.25 μg l−1) and Roundup OriginalDI (Roundup®; 0–0.75 μg active ingredient l−1), a glyphosate based-herbicide, on Elodea canadensis. Enro alone was not toxic, but the plants were highly sensitive to Roundup® whose toxicity is related to the induction of oxidative stress. The metabolism of Enro by plants into Ciprofloxacin (Cipro) was observed, and although former is not phytotoxic, oxidative events associated with Cipro generation were observed. The activity of cytochrome P450 was shown to be involved in Enro degradation in E. canadensis. As a cytochrome P450 inhibitor, Roundup® decreases Enro metabolism in plants. Enro, in turn, increases glyphosate uptake and toxicity, so that Enro and Roundup® have synergistic effects, disrupting the physiological processes of E. canadensis. Our results suggest E. canadensis as a potential candidate for the reclamation of Enro in contaminated waters, but not for Roundup® due to its high sensitivity to that herbicide.

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.

Grafting is an alternative method for the early production of Araucaria angustifolia seeds, and welding quality is essential for the success of the technique. The objective of this study was to create a classification of welding quality to estimate the percentage of scion survival. The patch and flute grafting techniques were used in a greenhouse and in the field. Survival was evaluated 270 days after grafting (DAG). At 60 DAG, observations of the graft connection region were made with the naked eye, classifying the connections into four welding classes. After 160 DAG, transverse cuts were performed on each class and visually and anatomically evaluated. Flute grafting presented higher initial survival (79%), but at 180 DAG, the survival rate of both techniques was similar (48% for flute and 41% for patch). There was greater scion survival for the class that had only two regions in contact with discontinuity in the bark. Stabilization of survival occurred after 180 DAG, regardless of the welding class. Visually, there were differences in welding quality; however, anatomically, all classes presented vascular connections. The visual welding quality assessment underestimated the percentage of scion survival. However, the vascular connection and development of parenchymatous tissue are promising for diagnosing grafting success. Grafting is an alternative method for the early production of Araucaria angustifolia seeds, and welding quality is essential for the success of the technique. The objective of this study was to create a classification of welding quality to estimate the percentage of scion survival. The patch and flute grafting techniques were used in a greenhouse and in the field. Survival was evaluated 270 days after grafting (DAG). At 60 DAG, observations of the graft connection region were made with the naked eye, classifying the connections into four welding classes. After 160 DAG, transverse cuts were performed on each class and visually and anatomically evaluated. Flute grafting presented higher initial survival (79%), but at 180 DAG, the survival rate of both techniques was similar (48% for flute and 41% for patch). There was greater scion survival for the class that had only two regions in contact with discontinuity in the bark. Stabilization of survival occurred after 180 DAG, regardless of the welding class. Visually, there were differences in welding quality; however, anatomically, all classes presented vascular connections. The visual welding quality assessment underestimated the percentage of scion survival. However, the vascular connection and development of parenchymatous tissue are promising for diagnosing grafting success.

Plinia peruviana is a species that is native to Brazil and is important due to the taste and medicinal properties of its fruits. Young leaves and split mature seeds were used as explants to initiate somatic embryogenesis to obtain a large number of plants in a short period of time. Leaf discs were cultured in MS medium containing various concentrations of 2,4-D (2,4-dichlorophenoxyacetic acid) or picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid). In the case of the mature seeds, various concentrations of glutamine, 2,4-D and a combination of auxin and BAP (6-benzylaminopurine) were tested for somatic embryogenesis induction. For somatic embryo maturation, several concentrations of PEG 6000 (polyethylene glycol; up to 90 g L-1) were tested. After 60 days of culture using leaf discs, callus formation occurred in all treatments, with the highest averages obtained with 10 μM 2,4-D. However, these calluses did not form somatic embryos. For the cultured seeds, the best treatment was the MS medium with 1,000 mg L-1 glutamine and 10 μM 2,4-D without BAP. The supplementation of 60 g L-1 PEG 6000 was sufficient to promote the maturation of the somatic embryos. Histological analyses of the calluses that were formed from leaf discs showed nonembryogenic characteristics. In contrast, the calluses that originated from mature seeds had small and round cells with little vacuolation, which are characteristics of embryogenic structures.

Fluoride (F) is the most phytotoxic atmospheric pollutant. The use of plants for passive or active biomonitoring has been a common strategy to detect abnormal atmospheric F concentrations. Tree species are mostly used, although the high sensitivities of some, associated with costly processes of plant replacement, will increase cost outlays associated with F-biomonitoring processes. After a few days of exposure, F-sensitive species often die, and must be replaced in active biomonitoring stations. We therefore investigated the potential use of the grass Panicum maximum for atmospheric F biomonitoring. Although that grass shows fast accumulations of F in their leaves, no visual symptoms of intoxication were observed. Despite of their F-tolerance, plants showed reliable microscopic responses to F (epicuticular wax erosion, plasmolysis of bulliform cells, and damage associated with trichomes). Since microscopic evaluations are mandatory in F-biomonitoring projects, the use of grass species such as P. maximum that show F-tolerance, fast F-uptake and reliable microscopic responses, could represent an option for F biomonitoring that would decrease costs related to plant production and replacement in monitoring stations.

Interacoes entre plantas e animais resultam em uma ampla variedade de adaptacoes nos individuos. Os herbivoros normalmente escolhem as plantas segundo o seu conteudo nutricional, sendo assim, as alteracoes na anatomia foliar, bem como na sua composicao quimica afetam diretamente os herbivoros. O objetivo deste trabalho foi investigar, em perspectiva temporal, se houve alteracoes estruturais e/ou quimicas nas folhas de Laguncularia racemosa em resposta ao desfolhamento macico de um bosque de manguezal causado pelo herbivoro exotico Hyblaea puera. Foram selecionados 10 individuos, dos quais foram coletadas, em intervalo de um ano, 25 folhas totalmente expandidas e fixadas nos 3° e 4° nos para a analise de atributos morfoanatomicos e histoquimica. Analise quimica do solo foi realizada em triplicata. Os dados foram avaliados estatisticamente por meio do teste t de Student e PCA em ambiente R. A PCA do solo evidenciou a diminuicao na salinidade inversamente relacionada com o aumento do indice de saturacao do Aluminio (H. AL) e da capacidade de troca cationica do solo (CTC). A PCA mostrou que os tres primeiros componentes explicaram 58,15% da variância total de dados analisados, sendo estes respectivamente a massa fresca, area herbivorada e espessura do limbo. Isso foi acompanhado pelo aumento da massa seca foliar, gerando maior resistencia a perfuracao do limbo, o que resultou na reducao de 92,40% da area foliar atacada pela herbivoria. Os testes histoquimicos evidenciaram alteracao na producao de composto metabolitos, com diminuicao na producao de taninos nos tecidos vasculares, o que possivelmente se justifica pela maior resistencia mecânica das folhas. Conclui-se que a herbivoria macica em L. racemosa foi preditora de ajustes ligados a defesa antiherbivoria de forma a reduzir o impacto negativo em outro evento predatorio de sua copa. Temporal pattern of herbivory and anti-hereditary fenders in the natural population of Laguncularia racemosa (Combretaceae) in mangroves massively predated by exotic herbivore of the species Hyblaea puera (Lepidoptera) A B S T R A C T Interactions between plants and animals result in a wide variety of adaptations in individuals. Herbivores typically choose plants according to their nutritional content, so changes in leaf anatomy as well as chemical composition directly affect herbivores. The aim of this work was to investigate, in a temporal perspective, if there were structural and / or chemical alterations in the leaves of Laguncularia racemosa in response to the massive defoliation of a mangrove forest caused by the exotic herbivore Hyblaea puera . Ten individuals were selected, from which 25 fully expanded and fixed at the 3rd and 4th nodes leaves were collected, in a one year interval, for the analysis of morphoanatomic and histochemical attributes. Soil chemical analysis was performed in triplicate. Data were statistically evaluated by Student's t-test and PCA in R environment. Soil PCA showed a decrease in salinity inversely related to an increase in Aluminum saturation index (H. AL) and soil cation exchange capacity (CTC). The PCA showed that the first three components accounted for 58.15% of the total variance of analyzed data, which were fresh mass, herbivorous area and limb thickness respectively. This was accompanied by an increase in leaf dry mass, leading to greater resistance to limb perforation, which resulted in a reduction of 92.40% of the leaf area attacked by herbivory. The histochemical tests showed alteration in the production of compound metabolites, with decrease in the production of tannins in the vascular tissues, which possibly is justified by the greater mechanical resistance of the leaves. It was concluded that the massive herbivory in L. racemosa was a predictor of adjustments related to the antiherbivory defense in order to reduce the negative impact on another predatory event of its crown. Key-words: functional adjustments, histochemistry; plant-herbivorous interactions; white mangrove.

Blueberries are valued for their taste and their high nutritional benefits, including their antioxidant and anti-inflammatory properties. In vitro culturing is an alternative method for clonal propagation, and has been used in many biotechnological studies. Most blueberry research is concentrated on highbush and lowbush taxa (Vaccinium corymbosum and Vaccinium angustifolium respectively), with only limited investigations of rabbiteye cultivars (Vaccinium virgatum) that are more suitable for subtropical climates and regions with warmer winters as a result of climate change. There is therefore a need to determine in vitro protocols for that species and group of cultivars. We examined here adventitious shoot regeneration in the ‘Delite’ rabbiteye blueberry cultivar. Leaf explants were cultured in vitro in Woody Plant Medium (WPM), and the effects of different thidiazuron (TDZ) concentrations, the orientation of the leaf (adaxial or abaxial surface in contact with the medium), and two portions of the leaf segment (basal or apical) were examined. De novo shoot development was studied using light and scanning electron microscopy. All concentrations of TDZ used showed similar survival and regeneration rates; 0.5 μM TDZ showed high efficiency in regenerating adventitious shoots (100%, with 57 adventitious shoots/explant), as did the adaxial surface in contact with the medium using either the apical or the basal portion of the leaf (97% shoot regeneration, 47.5 adventitious shoots/explant). Anatomical analyses showed direct and indirect organogenesis. The shoots developed leaf primordia with stomata, trichomes, and well-developed vascular tissues, with further elongation and rooting of the plants. We therefore describe here a high-efficiency regeneration method through de novo shoot organogenesis using TDZ in foliar explants of rabbiteye blueberry, with direct and indirect organogenesis., Ericaceae; Scanning electron microscopy (SEM); Light microscopy; Organogenesis; In vitro regeneration; Vaccinium virgatum; Horticulture; Plant growth; Plant physiology; Botany; Biotechnology.

The aim of this work was study the use of an experimental product containing chitosan and chelated cooper (Cu) as a sustainable tool for the protection of tomato plants, to understand which are the mechanisms involved in resistance promotion and what could be the anatomical changes on tomato leaves related to those defense responses. The experiment was conducted in a greenhouse with tomato plants grown in pots and subjected to weekly foliar sprays of a suspension containing chitosan associated with Cu-EDTA (ChiCu). The increase in the phenolic compound concentrations and phenylalanine ammonia-lyase (PAL) enzyme activities were detected 24 hours after. In addition, an increase was observed in the activity of chitinase and β-1,3-glucanase, enzymes related to defense responses. Also, an increase was found in the thickness of the outer periclinal wall on the adaxial epidermal surface in leaves submitted to 4 ml L-1 ChiCu. The proportion of the epiderm to the leaf blade was also higher. Although the pathogenicity-related enzymes were activated as well as phenolic compounds were increased, these changes did not affected the biometric and biochemical parameters related to the primary metabolism and essential for the maintenance of productive potential of tomato plants. The increase in the outer periclinal wall as a result of ChiCu sprays could have contributed to the resistance against diseases since it is the first barrier to the infection of a wide of pathogens.

Chemicals used to assure agricultural production and the feasibility of planting sites often end up in bodies of water used for crop irrigation. In a pot study, we investigated the consequences associated with the irrigation of maize with water contaminated by ciprofloxacin (Cipro; 0, 0.2, 0.8, 1.4 and 2.0 μg l−1) and/or glyphosate (0, 5, 25 and 50 mg l−1) on yields and food safety. Glyphosate in concentrations ≥25 mg l−1 prevented plant establishment, regardless of Cipro presence. Evaluations made at the V5 stage of plants reveal that Cipro concentrations ≥0.8 μg l−1 and glyphosate decreased photosynthesis and induced changes in leaf anatomy and stem biophysical properties that may contribute to decreased kernel yields. When those chemicals were applied together, kernel yield reductions were accentuated, evidencing their interactive effects. Irrigation with contaminated water resulted in accumulations of Cipro and glyphosate (as well as its metabolite, aminomethylphosphonic acid) in plant tissues. Accumulation of these chemicals in plant tissues such as leaves and kernels is a problem, since they are used to feed animals and humans. Moreover, these chemicals are of potential toxicological concern, principally due to residue accumulations in the food chain. Specially, the antibiotic residue accumulations in maize tissues can assist the induction of antibiotic resistance in dangerous bacteria. Therefore, we point out the urgency of monitoring the quality of water used for crop irrigation to avoid economic and food-quality losses.

The co-occurrence of aquatic contaminants, such as antibiotics and herbicides, has motivated investigations into their interactive effects on aquatic organisms. We examined the combined effects of environmental concentrations of the antibiotic Enrofloxacin (Enro; 0-2.25 μg l

Drift of the herbicides carfentrazone-ethyl and glyphosate may affect the initial growth of eucalyptus. This study aimed to assess the effect of carfentrazone-ethyl and glyphosate drift on photosynthesis, leaf morphoanatomy, and initial growth of two clones of Eucalyptus grandis. Two experiments were carried out in a 2 x 4 factorial scheme, in which factor 1 was represented by two clones of E. grandis and factor 2 by four herbicide underdoses (control, 86.4 g a.e. ha-1 of glyphosate, 3.0 g a.e. ha-1 of carfentrazone-ethyl, and the mixture of 86.4 g a.e. ha-1 of glyphosate + 3.0 g a.e. ha-1 of carfentrazone-ethyl). Herbicide application was carried out by simulating the drift in the lower third of seedling canopy. Assessments were performed 23 days after herbicide application. Both clones presented morphoanatomical changes such as erosion of epicuticular waxes and degeneration of epidermal and parenchymal cells, especially when exposed to carfentrazone-ethyl underdose or its mixture with glyphosate. The clone CLR 383 was the most affected by the tested herbicides and presented the highest injury, lowest initial growth, lowest dry matter, and highest reduction of photosynthetic rate when treated with herbicide mixture, followed by carfentrazone-ethyl and glyphosate underdoses. The initial growth, dry matter, and photosynthesis of the clone CLR 384 were not affected by the carfentrazone-ethyl underdose. Thus, both herbicides applied in isolation or in a mixture reduced the initial growth, dry matter, and photosynthesis of eucalyptus.

Silver nanoparticles (AgNPs) are widely used in consumer products due to their antibacterial property; however, their potential toxicity and release into the environment raises concern. Based on the limited understanding of AgNPs aggregation behavior, this study aimed to investigate the toxicity of uncoated (uc-AgNP) and coated with polyvinylpyrrolidone (PVP-AgNP), at low concentrations (0.5–100 ng/mL), under dark and visible-light exposure, using a plant test system. We exposed Allium cepa seeds to both types of AgNPs for 4–5 days to evaluate several toxicity endpoints. AgNPs did not cause acute toxicity (i.e., inhibition of seed germination and root development), but caused genotoxicity and biochemical alterations in oxidative stress parameters (lipid peroxidation) and activities of antioxidant enzymes (superoxide dismutase and catalase) in light and dark conditions. However, the light exposure decreased the rate of chromosomal aberration and micronuclei up to 5.60x in uc-AgNP and 2.01x in PVP-AgNP, and 2.69x in uc-AgNP and 3.70x in PVP-AgNP, respectively. Thus, light exposure reduced the overall genotoxicity of these AgNPs. In addition, mitotic index alterations and morphoanatomical changes in meristematic cells were observed only in the dark condition at the highest concentrations, demonstrating that light also reduces AgNPs cytotoxicity. The light-dependent aggregation of AgNPs may have reduced toxicity by reducing the uptake of these NPs by the cells. Our findings demonstrate that AgNPs can be genotoxic, cytotoxic and induce morphoanatomical and biochemical changes in A. cepa roots even at low concentrations, and that visible-light alters their aggregation state, and decreases their toxicity. We suggest that visible light can be an alternative treatment to remediate AgNP residues, minimizing their toxicity and environmental risks.

Titanium dioxide nanoparticles (TiO2NPs) are widely used and may impact the environment. Thus, this study used a high concentration of TiO2NP (1000 mg/L) to verify the defense mechanisms triggered by a plant system – an indicator of toxicity. Furthermore, this study aimed at completely characterizing TiO2NP suspensions to elucidate their toxic behavior. TiO2NPs were taken up by meristematic cells of Allium cepa, leading to slight inhibition of seed germination and root growth. However, severe cellular and DNA damages were observed in a concentration-dependent manner (10, 100, and 1000 mg/L). For this reason, we used the highest tested concentration (1000 mg/L) to verify if the plant cells developed defense mechanisms against the TiO2NPs and evaluated other evidences of TiO2NP genotoxicity. Nucleolar alterations and plant defense responses (i.e., increased lytic vacuoles, oil bodies and NP phase change) were observed in meristematic cells exposed to TiO2NP at 1000 mg/L. In summary, TiO2NPs can damage the genetic material of plants; however, plants displayed defense mechanisms against the deleterious effects of these NPs. In addition, A. cepa was found to be a suitable test system to evaluate the cyto- and genotoxicity of NPs.

Their continuous release into the environment, associated with their inherent biological activity, has motivated investigations into the detrimental effects of antibiotics and herbicides in natural and agricultural ecosystems. In this study, the interactive effects of the antibiotic ciprofloxacin (Cipro) and the herbicide Roundup on seed germination and root development were investigated. Although both compounds act as inhibitors of the mitochondrial electron transport chain in seeds, neither Cipro nor Roundup disrupted germinability of maize seeds. However, Cipro accelerated germination by promoting ROS accumulation in seeds, while the stimulatory effect of Roundup on ROS-scavenging enzymes (catalase and ascorbate peroxidase) seems to prevent ROS-signaling, delaying the germination process. Roundup reduced root elongation, possibly due to its interference with auxin production, thereby preventing cell division, while Cipro stimulated root elongation by increasing root oxidative status. Cipro and Roundup showed antagonistic effects on maize seeds and root physiology. The presence of the antibiotic is likely not to disturb plant development; however, its stimulatory effects were not sufficient to overcome the deleterious effects of Roundup. According to our results, glyphosate-based herbicides must be carefully used during maize cropping and although antibiotics such as Cipro may not negatively impact agricultural production, their accumulation by crops must be investigated since this can be a pathway of antibiotic-insertion into the food chain.

Our paper presents reliable anatomical characters of the pinnae that allowed the identification of the recognized species of Butia through a purely anatomical key, in which specific identification is performed by a set of up to five characters. Leaf anatomy, already used to support new taxa in related genera, can also be useful to validate questionable Butia species and differentiate between similar species, but surprisingly does not reflect the proposed phylogenetic relationship between species of this genus., Butia is a neotropical genus whose identification is based mostly on characters from external morphology, which are sometimes variable or inadequate for species differentiation. We aimed to verify if leaf anatomy of 18 Butia species brings new characters suitable for species identification and if it corroborates the phylogenetic relationship within the genus. Moreover, we propose an anatomical key to assist in species identification. Pinnae were collected and subjected to the usual techniques for light and scanning electron microscopies. The anatomical key was created with the aid of Xper2 software, based on the importance of characters to distinguish species according to the Jaccard index. All species have isobilateral mirrored mesophyll, amphistomatic leaves and secondary vascular bundles with sclerenchymatic sheath reinforcement connected to the hypodermis. Among the species studied, B. marmorii and B. matogrossensis showed exclusive characters. For the other species, up to five characters are sufficient for delimitation. Our anatomical key presents relevant characters that allow the identification of the recognized species of Butia. Reliable anatomical characters of easy observation, especially the raphides, are valuable in species distinction. Leaf anatomy, already used to support new taxa in related genera like Allagoptera and Syagrus, can also be useful to validate questionable Butia species and differentiate between similar species but do not reflect the proposed relationship between Butia species.

BACKGROUND: The response to infection of Austropuccinia psidii in resistant (CLR‐383) and susceptible (CLR‐384) Eucalyptus grandis clones, exposed to herbicide drift of carfentrazone‐ethyl, glyphosate and a mixture of these two herbicides, was evaluated at microscopic and physiological levels. RESULTS: Plants of the two clones showed symptoms of phytotoxicity caused by herbicide drift. However, net CO₂ assimilation rate, height and shoot dry matter were lower in CLR‐384 than in CLR‐383. At the ultrastructure level, the leaves of both clones exposed to the herbicides showed thylakoid disorganization and accumulation of starch grains in the chloroplasts. Only plants of CLR‐384 were infected by A. psidii, but when exposed to herbicide drift, rust severity was lower than in control plants. Six days after inoculation (dai), plants of this clone exposed to the herbicides had smaller uredinia than control plants. At 12 dai, non‐herbicide treated plants showed normal uredinia, containing abundant urediniospores. By contrast, plants exposed to the herbicides were less colonized by the fungus, and the uredinia were smaller with reduced production of urediniospores, which were sometimes not even detected. CONCLUSION: Glyphosate and carfentrazone‐ethyl herbicide drift reduce infection and uredinial formation of A. psidii and to some extent induce basal resistance in a susceptible clone of E. grandis. © 2018 Society of Chemical Industry

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.

We investigated biomarkers for early fluoride (F)-detection in the environment using the F-sensitive species Spondias dulcis. Plants were exposed to F (5 ml l−1) to determine the sequence of events preceding the visual appearance of the characteristic symptomatology of F toxicity. Decreases in photosynthetic rates in plants upon F exposure were related to decreasing stomatal conductance due to F-induced damage to guard-cells. Chlorophyll fluorescence was not a good indicator of F stress to plants, meanwhile the scanning electron microscopy and gas-analyzer evaluations were the best techniques to attest to atmospheric F concentrations using S. dulcis, since their results were predictive and preceded F-induced visual symptomatology in plant leaflets. Our results demonstrated that microscopic damage precedes physiological disturbances in sensitive plant species (such as S. dulcis) exposed to F.