RESUMO A expansão do agronegócio no Brasil, se deve em parte pela ampliação das áreas agricultáveis no Cerrado, o que, consequentemente, leva a um aumento do uso de herbicidas, entre eles o glifosato. Em vista disso, objetivou-se avaliar as respostas fisiológicas e morfoanatômicos de Bowdichia virgilioides Kunth. (Fabaceae), quando expostas ao herbicida glifosato, em condições controladas de casa de vegetação. Além disso, o estudo se propôs a identificar possíveis padrões de respostas da espécie estudada, com o propósito de fornecer subsídios para o estudo da espécie, em áreas atingidas por deriva deste herbicida. O delineamento experimental foi em blocos ao acaso, com sete doses do herbicida: 25, 50, 100, 200, 400, 800 e 1200 g i.a ha-1, além d o controle (0), com quatro repetições cada. Foram analisados: trocas gasosas, emissão de fluorescência da clorofila a, conteúdo de pigmentos cloroplastídicos, permeabilidade de membrana e características visuais e anatômicas. Os resultados mostraram que o glifosato é fitotóxico para B. virgilioides, pois, mesmo em doses baixas este herbicida foi capaz de afetar todos os parâmetros analisados. Houve também a confirmação da presença de compostos fenólicos, principalmente no parênquima paliçádico. As alterações metabólicas apresentadas, comprovam a sensibilidade de B. virgilioides ao glifosato. Dessa maneira, as respostas observadas, podem servir como ferramenta de diagnóstico dos efeitos da exposição de glifosato sobre essa espécie, presente em áreas nativas atingidas pela deriva deste herbicida. Seu uso indiscriminado é um risco à biodiversidade do Cerrado.

ABSTRACT The expansion of agribusiness in Brazil is partly due to the expansion of arable areas in the Cerrado biome, which, consequently, leads to an increase in the use of herbicides, including glyphosate. Therefore, the objective of this study was to evaluate the physiological and morphoanatomic responses of Bowdichia virgilioides Kunth. (Fabaceae), when exposed to the herbicide glyphosate, under controlled greenhouse conditions. In addition, the study proposed to identify possible response patterns of the studied species and provide subsidies for the study of the species in areas affected by the drift of the herbicide. The experimental design was in randomized blocks, with seven doses of the herbicide: 25, 50, 100, 200, 400, 800, and 1200 g i.a ha-1 besides the control (0), with four repetitions each. Gas exchange, chlorophyll a fluorescence emission, chloroplast pigment content, membrane permeability, and visual and anatomical features were analyzed. The results showed that glyphosate is phytotoxic to B. virgilioides because, even at low doses, this herbicide was able to affect all parameters analyzed. There was also confirmation of the presence of phenolic compounds, mainly in the palisade parenchyma. The metabolic alterations presented demonstrated the sensitivity of B. virgilioides to glyphosate. Thus, the observed responses can serve as a tool for diagnosing the effects of glyphosate exposure on this species, present in native areas affected by the drift of this herbicide. Its indiscriminate use poses a risk to Cerrado biodiversity.

Resumo A fenologia é muito importante para o entendimento dos ciclos das plantas, a repetição de eventos biológicos e as causas desses ciclos em relação a fatores abióticos e bióticos. Diante disto, objetivou-se com este trabalho avaliar a época de ocorrência e intensidade das fases fenológicas vegetativas e reprodutivas e suas correlações com fatores externos e a influência da radiação fotossinteticamente ativa na biometria de frutos de Campomanesia adamantium (Cambess.) O. Berg. O estudo foi conduzido em fazenda localizada no município de Rio Verde-GO, Brasil. A caracterização da fenologia foi feita em dez indivíduos adultos. As observações fenologia das fases fenológicas vegetativas foram feitas mensalmente e os eventos fenológicos, reprodutivos, semanalmente. Foram utilizados dois métodos para o registro dos eventos fenológicos: o percentual de intensidade de Fournier e o índice de atividade. Foram feitas também avaliações do número total e diâmetros transversal e longitudinal dos frutos de dois ramos por planta com maior e menor incidência de radiação. Verificou-se atividade de folhas jovens e adultas em Campomanesia adamantium em quase todo o período de estudo, exceto nos meses de maio e agosto, para folhas jovens. A presença de brotos também foi bastante intensa durante o período. Observou-se um ciclo de fenofases de reprodução rápido e intenso entre os meses de outubro e janeiro para C. adamantium. A incidência da radiação interferiu na dimensão e produção dos frutos. Frutos desenvolvidos em ramos de sombra tiveram número reduzido e valores biométricos inferiores em relação àqueles que cresceram em ramos de sol.

Abstract Phenology is very important to the understanding of plant cycles, the repetition of biological events, and the causes of these cycles in relation abiotic and biotic factors. The aim of this to evaluate the time of occurrence and intensity of the vegetative and reproductive phenological phases, their correlations with external factors, and the influence of photosynthetically active radiation in the fruit Campomanesia adamantium (Cambess.) O. Berg. The study was conducted on a farm in the municipality of Rio Verde, Brazil. The phenological characterisation was performed using ten adult plants. Phenological observations of vegetative and reproductive phenological phases were made monthly and weekly, respectively. The total number and the transverse and longitudinal diameters of the fruit of two branches per plant, with higher and lower incidence of radiation, were also evaluated. The young and adult leaves in Campomanesia adamantium were active for almost the entire study period, except the young leaves were inactive in the months of May and August. The presence of sprouts was also very high during the study period. There was a phenophase cycle of rapid and intense play between October and January for C. adamantium. The incidence of radiation interfered with the size and production of the fruit. Fruits that developed in the shadow of branches were fewer and their biometric values lower than those who developed in sunlight.

ABSTRACT The objective of this study was to evaluate the responses of Raphanus sativus to the application of the herbicide tepraloxydim by analyzing photosynthetic and biometric characteristics of the plants. The experiment was conducted in a greenhouse and treatments were instituted when the plants had five expanded leaves. The herbicide tepraloxydim was applied at doses of 0, 75, 100, and 125 g of active ingredient per hectare (g a.i. ha-1). The herbicide dose of 125 g a.i. ha-1 led to a small decrease in the photosynthetic rate, water use efficiency, effective quantum yield of PSII, rate of electron transport, and the concentration of chloroplastidic pigments in the leaves of R. sativus. On the other hand, there was a small increase in CO2 concentration in the substomatal chamber. The number of branches, leaves, flowers, plant height and dry mass of the stem and flowers were reduced more prominently in response to herbicide doses than the photosynthetic characteristics. Therefore, treatment with tepraloxydim inhibits the growth and formation of the leaves, branches and flowers of R. sativus at the stage of development analyzed. However, doses of 75, and 100 g a.i. ha-1 neither compromise the photosynthetic apparatus nor the stability of cell membranes.

RESUMO A seca é o fator ambiental que mais prejudica a produtividade das culturas. Alguns produtos químicos têm sido utilizados na agricultura para mitigar os danos causados por esse estresse nas plantas. Portanto, examinamos se a pulverização dos compostos sulfato de zinco (ZS), fosfito de potássio (FP) e doador de sulfeto de hidrogênio (H2S) - hidrossulfeto de sódio (NaHS) - mitigam os efeitos deletérios do déficit hídrico em plantas de girassol, analisando características fisiológicas e biométricas. O experimento foi conduzido em casa de vegetação sob delineamento de blocos ao acaso com cinco repetições. Os tratamentos foram arranjados em esquema fatorial 4 x 2: [Fator A (aliviadores)] - pulverização de FP (0.5 L ha-1), ZS (3.2 kg ha-1), NaHS (1.2 g ha-1), e água; [Fator B (umidade do substrato, US)] - 100% (bem irrigado) e 30% (déficit hídrico, DH) da capacidade de campo. Nas condições de DH, os aliviadores levaram à manutenção de maiores valores de potencial hídrico (ΨW), menor teor de malonaldeído foliar (MDA) e aumento da atividade da enzima antioxidante peroxidase (POX), exceto para ZS. Entretanto, o potencial osmótico foliar, a concentração de prolina, as variáveis relacionadas às trocas gasosas, fluorescência da clorofila a e as características biométricas diferiram apenas em função do fator US. Os resultados de ΨW e MDA em plantas de girassol sob DH são indicativos da capacidade mitigadora do ZS, FP e H2S. Assim, a pulverização desses compostos em plantas de girassol mitiga os efeitos do DH, atuando especificamente em processos fisiológicos relacionados a respostas antioxidantes e na manutenção de água nos tecidos foliares.

ABSTRACT Drought is the most harmful environmental factor crop productivity. Some chemicals are used in agriculture to mitigate the damage from this stress on plants. Therefore, we examined whether the spraying of zinc sulfate (ZS), potassium phosphite (KPhi) and the hydrogen sulfide (H2S) donor sodium hydrosulfide (NaHS) would mitigate the deleterious effects of water deficit on sunflower plants by analyzing physiological and biometric characteristics. The experiment was carried out in a greenhouse using a randomized block design with five replications. The treatments were arranged in a 4 x 2 factorial scheme: [Factor A (Alleviators)] - spraying of KPhi (0.5 L ha-1), ZS (3.2 kg ha-1), NaHS (1.2 g ha-1), and water; [Factor B (substrate humidity, SH)] - 100% (well irrigated) and 30% (water deficit, WD) of field capacity. Under WD conditions, alleviators led to the maintenance of higher values of water potential (ΨW), a lower content of leaf malonaldehyde (MDA), and increased activity of the antioxidant enzyme peroxidase (POX), except for ZS. However, leaf osmotic potential, proline concentration, variables related to gas exchange and chlorophyll a fluorescence, and biometric characteristics differed only according to the SH factor. The results of ΨW and MDA for sunflower plants under WD are indicative of the mitigating capacity of ZS, KPhi, and H2S. Thus, the spraying of these compounds on sunflower plants mitigates the effects of WD, acting specifically in physiological processes related to antioxidant responses and in the maintenance of water in leaf tissues.

RESUMO Algumas forrageias liberam no ambiente substancias alelopáticas, podendo inviabilizar o consórcio com espécies arbóreas em pastagens. O objetivo deste trabalho foi avaliar características fotossintéticas do pequizeiro influenciadas por concentrações de resíduos das espécies forrageiras Urocholoa decumbens, Melinis minutiflora e Paspalum notatum. Os tratamentos consistiram do cultivo de pequi sob resíduos da parte aérea das três espécies forrageiras misturadas ao substrato em quatro concentrações (1, 2, 3 e 4% massa/massa), mais um tratamento adicional (testemunha comparativa) com pequi cultivado no substrato sem resíduos. Foi avaliada a taxa fotossintética, condutância estomática, taxa transpiratória, relação entre a concentração interna e externa de CO2 (Ci/CA), rendimento quântico máximo, rendimento quântico efetivo do FS II, taxa de transporte de elétrons, quenching não fotoquímico e índice clorofilog referente ao conteúdo das clorofilas a, b e total em plantas de pequi aos 50 e 100 dias após o transplantio (DAT) e a produção relativa referente à matéria seca aos 100 DAT. Aos 50 DAT, as plantas de pequi foram afetadas quanto as variáveis fotossintéticas A, g s , clorofila a, clorofila b e clorofila total, quando cultivadas na presença de resíduos das forrageiras. Aos 100 DAT, as plantas de pequi foram afetadas quanto as variáveis fotossintéticas A, Fv/Fm, ETR, NPQ, clorofila a, clorofila b e clorofila total, quando cultivadas na presença de resíduos das forrageiras. O pequizeiro tem produção de matéria seca relativa reduzida quando cultivado na presença de resíduos da espécie U. decumbens. Essa variável também é afetada quando o pequi é cultivado em concentrações crescentes de resíduos das espécies U. decumbens, M. minutiflora e P. notatum.

ABSTRACT Some forages release allelopathic substances into the environment, and may prevent consortium with arboreal species in pastures. The objective of this work was to evaluate photosynthetic characteristics of pequizeiro plants (hereafter pequi) influenced by concentrations of residues of the forage species Urocholoa decumbens, Melinis minutiflora and Paspalum notatum. The treatments consisted of pequi cultivation under aerial residues of the three forage species mixed to the substrate in four concentrations (1, 2, 3 and 4% mass/mass), plus an additional treatment (comparative control) with pequi cultivated on the substrate without waste. The following parameters were evaluated: photosynthetic rate, stomatal conductance, transpiration rate, relationship between internal and external CO2 concentration (Ci/Ca), maximum quantum yield, effective quantum yield of FS II, electron transport rate, nonchemical quenching and chlorophyll index, concerning the content of chlorophyll a, b and total in pequi plants at 50 and 100 days after transplanting (DAT), and the relative production of dry matter at 100 DAT. At 50 DAT, the following photosynthetic variables were affected in pequi plants: A, gs, chlorophyll a, chlorophyll b and total chlorophyll when cultivated in the presence of forage residues. At 100 DAT, the following photosynthetic variables were affected in pequi plants: A, Fv/Fm, ETR, NPQ, chlorophyll a, chlorophyll b and total chlorophyll, when cultivated in the presence of forage residues. Pequi plants had reduced relative dry matter yield when grown in the presence of U. decumbens. This variable was also affected when pequi was grown in increasing concentrations of residues of the species U. decumbens, M. minutiflora and P. notatum.

ABSTRACT Hyptis marrubioides Epling, Lamiaceae, a species from Brazilian Cerrado, has been used against gastrointestinal infections, skin infections, pain, and cramps. Herein, H. marrubioides seedlings were cultured in vitro under different wavelengths (white, blue, green, red, and yellow) with 50 µmol m-2 s-1 irradiance and a 16-h photoperiod. After 20 and 30 days of cultivation, shoot length, leaf number, fresh mass, and dry mass were evaluated. The flavonoid rutin content was determined by the HPLC-DAD method. The shoots were longer in plants cultivated under yellow (16.603 ± 0.790 cm, 1.8-fold), red (15.465 ± 0.461 cm, 1.7-fold), and green (14.677 ± 0.737 cm, 1.6-fold) lights than in control plants exposed to white light (9.203 ± 0.388 cm). The number of leaves increased in plants exposed to red (23.425 ± 1.138, 1.1-fold) and green (22.725 ± 1.814, 1.1-fold) lights, compared to control plants (20.133 ± 0.827). Fresh (0.665 ± 0.048 g, 1.2-fold) and dry (0.066 ± 0.005 g, 1.3-fold) mass of seedlings were the highest in seedlings grown under red light, compared to seedlings grown under white light (0.553 ± 0.048 and 0.028 ± 0.004, respectively). However, rutin production was higher under white (0.308 mg g-1 of dry weight) and blue lights (0.298 mg g-1 of dry weight). Thus, red light induces plant growth and increases leaf number and dry weight in in vitro-cultivated H. marrubioides, whereas blue and white lights promote the greatest rutin accumulation.

ABSTRACT The maturing of drift used in the culture of sugar cane can have harmful effects on other crops grown in the vicinity of sugar cane plantations. Among these, sunflower grown in the off-season can have its growth and productivity affected by drift. The objective of this research was to evaluate whether the drift of trinexapac-ethyl and glyphosate promotes changes in the photosynthetic metabolism of sunflower plants. Two trials were carried out to evaluate the effects of these products on gas exchange, chlorophyll fluorescence, chloroplastid pigments, membrane permeability, sugar content, as well as shikimic acid and malondialdehyde concentration in the treated plants. In the first experiment, we tested glyphosate in doses of 0 (control); 3.6; 7.2; 14.4; 28.8; and 86.4 g a.e.∙ha−1 and in the second, trinexapac-ethyl at doses of 0 (control) 3.12; 6.25; 12.50; 25, and 75 g a.i.∙ha−1. The growth regulator trinexapac-ethyl did not change the photosynthetic metabolism of plants. However, glyphosate caused damage to the photosynthetic apparatus and a reduction in the carbohydrate concentration and chloroplastid pigments, with casual damage to cell membranes; these effect were more intense at increased doses. The effects of glyphosate were evidenced by the increased concentration of shikimic acid, derived from its mechanism of action. Concludes that, the photosynthetic metabolism of sunflower plants is not affected by the growth regulator trinexapac-ethyl, unlike to the evident effects after application of glyphosate.

RESUMO O objetivo desta pesquisa foi avaliar a fitointoxicação e a anatomia foliar de plantas de pequi (Caryocar brasiliense Cambess.) submetidas à deriva simulada do glifosato. O delineamento utilizado foi em blocos casualizados com nove repetições. A unidade experimental foi constituída por um vaso, com capacidade de 18 litros, contendo uma planta. Os tratamentos corresponderam à aplicação das doses de 0 (controle), 50, 100, 250, 500, 1000 e 1500 g e.a. ha-1 de glifosato. Avaliações visuais de fitointoxicação foram realizadas aos 7, 14 e 21 dias após a aplicação (DAA) dos tratamentos por meio de notas expressas em escala percentual, em que zero e cem representaram ausência de sintomas e morte das plantas, respectivamente. Descrição dos sintomas, alterações na anatomia foliar e micromorfometria foram realizadas em folhas do ápice e do terço médio aos 23 DAA. Os sintomas visuais de intoxicação foram murcha, clorose seguida de necrose, enrolamento das folhas dos ápices e senescência foliar, sendo intensificadas com o aumento das doses. As alterações anatômicas nas folhas foram detectadas a partir da dose de 250 g ha-1. Os danos causados foram células plasmolisadas, ruptura da epiderme, células alteradas, hiperplasia, células colapsadas, tecidos necrosados e acúmulo de compostos fenólicos.

ABSTRACT The goal of this research was to examine phytotoxicity and leaf anatomy of pequi plants (Caryocar brasiliense Cambess.) exposed to simulated drift of glyphosate. The experimental design was randomized blocks with nine replications. Each experimental unit was composed by one 18-L pot with one plant. The treatments consisted of different doses of glyphosate sprayed: 0 (control), 50, 100, 250, 500, 1000 and 1500 g ae ha-1 of glyphosate. Phytotoxicity visual ratings were carried out at 7, 14 and 21 days after spraying (DAS) by scores expressed in a percentage scale, within which zero and one hundred represent no symptom and plant death, respectively. Description of symptoms, changes in leaf anatomy and micromorphometric analysis were performed on leaves taken from plant top and middle third at 23 DAS. Poisoning symptoms were wilting, chlorosis followed by necrosis, winding of top leaves and leaf senescence, being intensified with increasing doses. Leaf anatomical changes were detected from the dose of 250 g ha-1. The observed damages consisted of plasmolized cells, epidermal disruption, distorted cells, hyperplasia, cell collapsing, necrotic tissue and accumulation of phenolic compounds.

RESUMO Sorghum arundinaceum (Desv.) Stapf é uma planta daninha pertencente à família Poaceae e encontra-se disseminada em todo o território brasileiro. Apesar da ocorrência frequente, infestando áreas cultivadas, são poucas as pesquisas concernentes à biologia e à fisiologia desta espécie. Objetivou-se com esta pesquisa avaliar o crescimento, a partição de fotoassimilados e as características fisiológicas da planta daninha Sorghum arundinaceum, em casa de vegetação. As plantas foram coletadas em intervalos regulares de sete dias, a partir de 22 e até 113 dias após o transplantio (DAT). Em cada coleta, determinaram-se altura de plantas, volume de raiz, área foliar e massa seca e, posteriormente, aplicou-se a análise de crescimento, sendo calculada a partição de massa seca entre os órgãos, o acúmulo de massa seca, a área foliar específica, a taxa de crescimento relativo e a razão de peso foliar. Aos 36, 78 e 113 DAT foram avaliadas as taxas fotossintética e transpiratória, a condutância estomática, a relação entre a concentração interna e externa de CO2 e a fluorescência da clorofila a. O Sorghum arundinaceum apresentou a altura de 1,91 metros, com crescimento inicial lento e alocou grande parte da biomassa nas raízes. A taxa fotossintética e o rendimento quântico máximo do FS II são semelhantes, durante todo o ciclo de crescimento. Na maturação, o Sorghum arundinaceum apresenta maiores valores de taxa transpiratória, condutância estomática e coeficiente de dissipação não fotoquímico (NPQ).

ABSTRACT Sorghum arundinaceum (Desv.) Stapf is a weed that belongs to the Poaceae family and is widespread throughout Brazil. Despite the frequent occurrence, infesting cultivated areas, there is little research concerning the biology and physiology of this species. The objective of this research was to evaluate the growth, carbon partitioning and physiological characteristics of the weed Sorghum arundinaceum in greenhouse. Plants were collected at regular intervals of seven days, from 22 to 113 days after transplanting (DAT). In each sample, we determined plant height, root volume, leaf area and dry matter, and subsequently we perfomed the growth analysis, we have determined the dry matter partitioning among organs, the accumulation of dry matter, the specific leaf area, the relative growth rate and leaf weight ratio. At 36, 78 and 113 DAT, the photosynthetic and transpiration rates, stomatal conductance, CO2 concentration and chlorophyll fluorescence were evaluated. The Sorghum arundinaceum reached 1.91 in height, with slow initial growth and allocated much of the biomass in the roots. The photosynthetic rate and the maximum quantum yield of FSII are similar throughout the growth cycle. At maturity the Sorghum arundinaceum presents higher values of transpiration rate, stomatal conductance and non-photochemical quenching coefficient (NPQ).