Cytogenetic studies were carried out on five accesses of interspecific hybrids of Pennisetum purpureum and Pennisetum glaucum and their parentals, which are part of the Forage Germplasm Bank of the Centro Nacional de Pesquisa de Gado de Leite of EMBRAPA, Brazil. The mitotic cytogenetic analysis, performed using stain by Schiff reactive, confirmed the chromosome number of 2n = 14, 28 and 21 for the accesses of P. glaucum, P. purpureum and their hybrids, respectively. For each access, descriptions of the chromosome complement and idiograms are presented which allowed to establish the karyotypic relationships between the hybrids and their parentals. Based on the total chromosomal length data it was possible to establish the karyotype classification of the accesses concerning symmetry. While the karyotype of P. glaucum accesses was considered symmetric, hybrids presented asymmetric karyotypes. For P. purpureum, two accesses (BAGs 63 and 75) showed symmetric karyotype and three (BAGs 54, 65 and 91) were asymmetric. For the interspecific hybrids it was possible to infer the origin of some parental chromosomes based on the total chromosomal length measurements, satellite presence and chromosome morphology. INDEX TERMS:Elephant grass, pearl millet, interspecific hybrids, cytogenetic, ideograms, chromosome. CITOGENÉTICA DE HÍBRIDOS ENTRE Pennisetum purpureumSchumack E Pennisetum glaucum L. E SEUS GENITORES RESUMO Foram realizados estudos citogenéticos em quinze acessos do Banco de Germoplasma Forrageiro, da Embrapa Gado de Leite, sendo cinco híbri-dos interespecíficos de Pennisetum purpureum e Pennisetum glaucum e seus genitores. As análises citogenéticas mitóticas realizadas mediante coloração com reativo de Schiff confirmaram o número cromossômico de 2n =14, 28 e 21 para os acessos de P. glaucum, P. purpureum e híbridos, respectivamente. Para cada um desses acessos, foram realizadas descrições do complemento cromossômico e idiogramas, as quais possibilitaram estabelecer relações cariotípicas entre os híbridos e seus genitores. Com base nos dados de comprimento total do cromossomo, foi estabelecida a classificação do cariótipo dos acessos com relação à simetria. Os cariótipos dos acessos de P. glaucum foram considerados simétricos, ao passo que os híbridos apresentaram cariótipos assimétricos. Para P. purpureum, dois acessos (BAGs 63 e 75) mostraram cariótipos simétricos e três (BAGs 54, 65 e 91) assimétricos. Nos híbridos interespecíficos entre P. purpureum e P. glaucum, foi possível inferir a procedência de alguns cromossomos parentais com base nas medidas de comprimento total do cromossomo, presença de satélite e morfologia do cromossomo.

Copper oxide nanoparticles (CuO NPs) are employed in antifouling paints, and chromium oxide nanoparticles (Cr 2 O 3 NPs) have been used as a green pigment. Their extensive use can contaminate aquatic ecosystems, and the toxicological effects of these NPs to the biota are poorly known. In this study, we evaluated the acute toxicity induced by CuO (15-30 nm) and the higher zeta potential may have contributed to the higher stability in suspension and less potential for agglomeration, partially explaining the higher toxicity of NPs in relation to Cr(NO 3 ) 3 . After the tests, we observed morphological damages such as increase in fat droplets, internal organ exposure and partially disintegration in organisms exposed to all tested substances, NPs or the salts.

) RESUMOO objetivo deste estudo foi duplicar o complemento cromossômico de híbridos triplóides de capimelefante e milheto para obtenção de plantas hexaplóides férteis. Esta estratégia permitirá o uso de hexaplóides em programas de melhoramento genético do capim-elefante, por meio da transferência de alelos com as características desejadas, tornando possível sua propagação via semente. Seedlings, plântulas e segmentos caulinares cultivados in vitro foram tratados com colchicina a 0,05% ou 0,1% aplicadas por 12 ou 24 horas. Seedlings de genótipos híbridos diferentes e meristemas de dois híbridos interespecíficos cultivados in vivo foram tratados por 24 horas com colchicina a 0,05%. A duplicação cromossômica foi confirmada pela contagem de cromossomos em células meristemáticas de pontas de raízes. A viabilidade polínica, os testes de germinação in vitro e a produção de sementes foram utilizados para avaliar a fertilidade dos hexaplóides. Seedlings cultivados in vitro e tratados com colchicina a 0,1% por 24 horas tiveram a melhor resposta à indução de poliploidia; em 38% das plantas sobreviventes observaram-se o conjunto cromossômico duplicado e a presença de pólens viáveis, confirmando a fertilidade dos hexaplóides.Palavras-chave: Duplicação cromossômica, colchicina, poliploidia, híbrido interespecífico, Pennisetum purpureum, Pennisetum glaucum. ABSTRACT CHROMOSE DUPLICATION OF TRIPLOID HYBRIDS BETWEEN ELEPHANTGRASS AND PEARL MILLETThe aim of this study was to duble the chromose number of elephantgrass and pearl millet triploid hybrids in order to obtain hexaploid fertile plants. This strategy would allow the use of the hexaploids in the elephantgrass breeding program as a bridge for transfering alleles of desired characteristics and making possible propagation by seed. Seedlings, plantlets and stem segments were cultivated in vitro and treated with 0.05% or 0.1% colchicine for 12 or 24 h. Seedlings of different hybrid genotypes and meristems of two interspecific hybrids were cultivated in vivo and treated for 24 h with 0.05% colchicine. Chromose duplication was confirmed by countings in the root tip cells. Pollen viability, in vitro

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Some macrophytes species show a high growth potential, colonizing large areas on aquatic environments. Cattail (Typha angustifolia L.) uncontrolled growth causes several problems to human activities and local biodiversity, but this also may lead to competition and further problems for this species itself. Thus, the objective of this study was to investigate anatomical modifications on T. angustifolia plants from different population densities, once it can help to understand its biology. Roots and leaves were collected from natural populations growing under high and low densities. These plant materials were fixed and submitted to usual plant microtechnique procedures. Slides were observed and photographed under light microscopy and images were analyzed in the UTHSCSA-Imagetool software. The experimental design was completely randomized with two treatments and ten replicates, data were submitted to one-way ANOVA and Scott-Knott test at p<0.05. Leaves from low density populations showed higher stomatal density and index. These modifications on stomatal characteristics were more evident on the leaf abaxial surface. Plants from low density populations showed thicker mesophyll and higher proportion of aerenchymal area. Roots from low density populations showed a higher proportion of the vascular cylinder. Whereas, plants from higher density populations showed greater thickness of the endodermis, exodermis, phloem and root cortex. Higher density populations showed a higher proportion of aerenchymal gaps in the root cortex. Therefore, cattail plants from populations growing under high density population show anatomical traits typical of plants under stress, which promotes the development of less functional anatomical modifications to aquatic environments.Keywords: anatomical plasticity, cattail, macrophytes, plant handling, eutrophication, stress. Características anatômicas relacionadas ao estresse em altas densidades populacionais de Typha angustifolia L. (Typhaceae)

Resumo -Objetivou-se com esse trabalho avaliar a fitotoxicidade de cinco concentrações de chumbo na germinação, anatomia radicular, e divisão celular de alface. Cipselas de alface foram colocadas em placas de Petri com papel de filtro e 2,5 mL de solução contendo 0,0; 0,5; 1,0; 2,0 e 5,0 mM de Pb(NO 3 ) 2 . As placas permaneceram em câmara do tipo B.O.D. a 25°C com fotoperíodo de 12 h, sendo avaliadas as seguintes variáveis: germinação, crescimento inicial, anatomia radicular, índice mitótico e frequência de anormalidades cromossômicas no meristema apical radicular. O delineamento estatístico foi inteiramente casualizado com cinco tratamentos e quatro repetições. Os dados foram submetidos à análise de variância e regressão. A germinação das sementes e o crescimento inicial das plântulas foram reduzidos proporcionalmente ao aumento nas concentrações de chumbo. A anatomia radicular apresentou reduções nas barreiras apoplásticas e modificações do xilema relacionadas com um aumento na condutividade hidráulica na presença de chumbo. O índice mitótico foi reduzido e as anormalidades cromossômicas foram aumentadas na presença das diferentes concentrações de chumbo. O sistema radicular da alface foi mais afetado que a parte aérea pelas doses de chumbo e os sintomas de fitotoxicidade mostraram-se relacionados a redução no índice mitótico do meristema apical radicular e maior condução de chumbo para a parte aérea. Palavras-chave -Bioindicadores. Citogenética. Lactuca sativa. Metais pesados. Mudanças estruturais.Abstract -This work aimed to evaluate the phytotoxicity of five lead concentrations on germination, root anatomy and cell cycle of lettuce. Lettuce cypselae were placed in Petri dishes covered with filter paper and 2.5 mL of solution containing 0.0, 0.5, 1.0, 2.0 and 5.0 mM of Pb(NO 3 ) 2 . Dishes were maintained in growth chamber B.O.D. type at 25ºC and photoperiod of 12 h, the following variables were evaluated: germination percentage, early growth, root anatomy, mitotic index and the rate of chromosomal abnormalities on root apical meristem. The seed germination and seedlings early growth were both reduced proportionally to the increase in lead concentrations. The root anatomy showed decreases in apoplastic barriers and modifications on the xylem related to the increase of hydraulic conductivity in the presence of lead. There were reductions in the mitotic index and na increase in chromosomal abnormalities under the different lead concentrations. Therefore, the lettuce root system were more affected by lead concentrations and the phytotoxicity symptoms are related to the reductions on mitotic index on root apical meristem and anatomical modifications related to higher lead translocation to plant shoots.

Resumo -O objetivo deste trabalho foi avaliar métodos de duplicação cromossômica, com uso de agentes antimitóticos e diversos materiais botânicos como explantes dos híbridos entre capim-elefante (Pennisetum purpureum Schum.) e milheto (Pennisetum glaucum (L.) R. Br.). Utilizaram-se soluções de colchicina a 50 mg L -1 e 100 mg L -1 , e de ciclohexamida 25 mg L -1 :8-hidroxiquinoleína 300 mg L -1 (1:1), aplicadas in vitro em segmentos nodais, e in vivo em plântulas e perfilhos, com diferentes períodos de exposição. O efeito dos antimitóticos foi avaliado por meio da taxa de sobrevivência, do número cromossômico e da presença de anomalias no ciclo celular, em meristemas de raízes das plantas sobreviventes. A colchicina apresentou melhor efeito sobre as plântulas, enquanto a ciclohexamida:8-hidroxiquinoleína (1:1) atuou melhor sobre os perfilhos. Observou-se ocorrência de mixoploidia em células que apresentaram de 14 até 42 cromossomos, o que indica que houve duplicação seguida de eliminação cromossômica, confirmada pelas aberrações cromossômicas. Das células analisadas 86,4%, em média, apresentaram número cromossômico diferente de 21.Termos para indexação: Pennisetum purpureum, Pennisetum glaucum, análise citogenética, eliminação cromossômica, híbrido interespecífico. Mixoploidy in napiergrass x pearl millet hybrids treated with antimitotic agentsAbstract -The objective of this work was to evaluate methods of chromosome duplication, using antimitotic agents and several botanical materials as explant hybrids between napiergrass (Pennisetum purpureum Shum.) and pearl millet (Pennisetum glaucum (L.) R. Br.). Colchicine (50 mg L -1 and 100 mg L -1 ) and cycloheximide:8-hydroxyquinoline (1:1) (25 mg L -1 :300 mg L -1 ) solutions have been applied in vivo to shoots and in vitro to seedlings and tillers. The antimitotic effect has been evaluated through survival rate, chromosome number and presence of cell cycle anomalies at the root tips of surviving plants. The best results have been obtained when seedlings have been treated with colchicine and tillers with cycloheximide: 8-hydroxyquinoline. Mixoploidy has been observed in cells having 14 to 42 chromosomes, indicating that duplication, followed by chromosome elimination, has occurred, which has been confirmed by chromosome aberrations. In the average, 86.4% of the analyzed cells have presented a chromosome number different from 21.Indexs terms: Pennisetum purpureum, Pennisetum glaucum, cytogenetic analysis, chromosome elimination, interespecific hybrid. IntroduçãoA intensificação da produção de leite de vacas alimentadas exclusivamente em pasto constitui um dos principais objetivos da pecuária nacional. Para tanto, tornase necessária a utilização de gramíneas forrageiras com maior potencial de produção de forragem e qualidade nutritiva. Neste sentido, destaca-se o capim-elefante, associado a outras características forrageiras favoráveis, tais como boa qualidade, palatabilidade, vigor e persistência.Essas características têm estimulado não só o cultivo dessa espécie, com...

The objectives of this study were to perform the physicochemical characterization of chitosan, to evaluate its effects on germination, early growth, root anatomy and on the cell cycle of two maize hybrids. The hybrids DKB 390 and DKB 390 VTPRO (transgenic) were used. DKB390 VTPRO is from Monsanto, and the event number is 89034, which expresses the proteins Cry1A105 and Cry2AB2. For the physico-chemical characterization of chitosan, the following analyzes were performed:, elemental analysis, total ash, infrared absorption spectroscopy, nuclear magnetic resonance, powder X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and viscosity. With the analysis of infrared absorption spectroscopy, nuclear magnetic resonance, powder X-ray diffraction, thermogravimetric and elemental analysis it was observed that the structure of chitosan presents a low level of deacetylation. Chitosan had a total ash value of 1.32% and high viscosity. By scanning electron microscopy the chitosan was classified as porous and fibrous structure. Increase in the seed germination rate was observed in both maize hybrids in the presence of chitosan, without changes in the initial growth. The cell analyzes showed that the chitosan was not toxic even at high concentrations, since the mitotic index remained unchanged and no chromosomal abnormalities were detected. The effects of chitosan in root anatomy were evaluated through the measurements of sections of root tips on histological preparations, and the genetically modified hybrid presented the best results. As conclusion, the use of chitosan in appropriate concentrations may favor the development of maize (especially transgenic) acting on germination or changing the root anatomy and consequently increasing resistance and adaptation of the seedlings to adverse conditions.