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Dive into the research topics where José Antonio Pimenta is active.

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Brazilian Journal of Botany | 1998

Anatomia ecológica de Sebastiania commersoniana (Baillon) Smith & Downs (Euphorbiaceae) submetida ao alagamento

Rosana M. Kolb; Moacyr Eurípedes Medri; Edmilson Bianchini; José Antonio Pimenta; Patricia C. Giloni; Geraldo T. Correa

In the woods along the Tibagi River hydrographical basin, in areas subject to periodical flooding, the incidence of S. commersoniana is usual, it often becoming the prevailing species. Plants of this species were kept in well drained and flooded soils for two months, in order to explain some aspects of tolerance to waterlogging. After this period, some plants were returned to the well drained soil in order to check the species behaviour in the re-aeration period. In the roots, flooding induced, an increase of intercellular spaces as well as a thickening of the cortex, and a reduction in the thickeness of the central cylinder. Flooded plants grew less than the control ones, and developed hypertrophic lenticels and some adventitious roots. The re-aired plants recovered in growth. It can be suggested that the morphoanatomical modifications observed are important to explain the tolerance of this species to flooding, if we take into consideration the obtained results, together with those obtained in the literature about floristic and phytosociology, as well as in that dealing with biochemistry.


Brazilian Archives of Biology and Technology | 2002

Photosynthesis, growth and development of Tabebuia avellanedae Lor. ex Griseb. (Bignoniaceae) in flooded soil

Viviane M. Davanso; Luiz Antonio de Souza; Moacyr Eurípedes Medri; José Antonio Pimenta; Edmilson Bianchini

Foram estudadas as modificacoes morfo-anatomicas e ecofisiologicas que o alagamento provoca em Tabebuia avellanedae Lor. ex Griseb. (Bignoniaceae), correlacionando-as com sua capacidade de tolerar o excesso de agua no solo. Plantas com tres meses de idade, crescendo em casa de vegetacao, foram submetidas a 56 dias de alagamento e a um periodo de pos-alagamento. A taxa fotossintetica e o crescimento de T. avellanedae decresceram conforme aumentou o tempo de alagamento, mas mesmo nao sendo altamente tolerante, a especie foi capaz de se adaptar a curtos periodos de alagamento. Esta relativa tolerância provavelmente se deve a capacidade apresentada por T. avellanedae de desenvolver estruturas que amenizam os efeitos do alagamento, promovendo a difusao interna de oxigenio da parte aerea para as raizes, tais como rachaduras caulinares, raizes superficiais e lenticelas hipertrofiadas nas raizes. Como nao houve acentuada variacao na anatomia interna de folhas e raizes de T. avellanedae, alteracoes metabolicas provavelmente auxiliaram na sobrevivencia da especie durante o alagamento.


Acta Botanica Brasilica | 2008

Tolerância à inundação de Cecropia pachystachya Trec. (Cecropiaceae): aspectos ecofisiológicos e morfoanatômicos

Claudia Universal Neves Batista; Moacir Eurípedes Medri; Edmilson Bianchini; Cristiano Medri; José Antonio Pimenta

To elucidate certain aspects of hypoxia tolerance in Cecropia pachystachya, plants were submitted to 30 days of flooding. Growth and development, stomatal conductance, photosynthetic rates and morpho-anatomy were studied. Root and stem relative growth rates (RGR) were lower in flooded plants. There was no difference in leaf RGR and whole plant RGR. The maintenance of leaf RGR is possibly related to greater sclerophylly in flooded plants. Stomatal conductance and photosynthetic rate decreased due to flooding. Stems and roots, especially the latter, showed morpho-anatomical alterations in flooded plants. The results so far suggest that flood tolerance in C. pachystachya is related to the capacity to maintain satisfactory energy production. The maintenance of a positive energy balance allows this species to maintain a substantial RGR, even under stress with a lower photosynthetic rate. Therefore C. pachystachya may be a strong competitor in flooded areas.


Oecologia Brasiliensis | 1998

ADAPTATIONS TO FLOODING BY TROPICAL TREES: MORPHOLOGICAL AND ANATOMICAL MODIFICATIONS

José Antonio Pimenta; Edmilson Bianchini; Moacyr Eurípedes Medri

Many plant communities subjected to flooding are found in tropical regions and are rich in tree species. Little is known about the flood-tolerance mechanisms these species have developed. However, studies have shown that metabolic, morphological and anatomical adaptations are all important for the survival of these plants in oxygen-deficient conditions. Lenticels hypertrophy, aerenchyma formation, stem hypertrophy and the formation of adventitious roots are among the morphological and anatomical adaptations caused by flooding. These modifications enhance the oxygenization of submerged roots, permitting sufficient energy production for survival. Ethylene, which increases markedly in flooded plants, seems to be the main hormone involved in bringing about these morphological modifications. In the case of the initiation and development of adventitious roots there is a synergism between ethylene and auxin. Broader studies are now necessary to improve the understanding of these questions because of the complexity of the responses of tropical tree species to flooding.


Brazilian Journal of Botany | 1998

Aspectos morfo-anatômicos e fisiológicos de Peltophorum dubium (Spr.) Taub. submetida ao alagamento e à aplicação de etrel

Moacyr Eurípedes Medri; Edmilson Bianchini; José Antonio Pimenta; Marcos F. Delgado; Geraldo T. Correa

The effects of flooding and ethrel application on P. dubium for a 70-day period were studied in order to elucidate the aspects of plants tolerance to hypoxia. During the experiment the thickness of the stem base, and the allocation of dry matter for the roots, stems and leaves were evaluated. Flooding increased both the thickness of the stem base as well as a great hypertrophy of the lenticels. The ethrel application did not induce the formation of adventitious roots, but it stimulated the hypertrophy of lenticels. The flooding and/or ethrel application significantly affected the growth and development of the plants. This effect was greater in the flooded plants which had their lenticels sealed. The results show that P. dubium can tolerate periods of flooding, possibly because of the morpho-anatomic modifications induced by variations in the hormone levels, led by ethylene.


Brazilian Journal of Botany | 1998

Metabolismo respiratório de raízes de espécies arbóreas tropicais submetidas à inundação

G.D Rogge; José Antonio Pimenta; Edmilson Bianchini; Moacyr Eurípedes Medri; Sandra Colli; L.M.T Alves

Aiming at elucidating certain aspects of the respiratory metabolism of roots of flood-tolerant tropical tree species (Lonchocarpus muehlbergianus, Sebastiania commersoniana and Sesbania virgata) as well as flood-intolerant species (Peltophorum dubium and Schinus terebinthifolius), plants were submitted to 2, 10 and 60 days of flooding. After these periods, the absorption of O2 and liberation of CO2 by the roots were determined. The respiratory metabolism of the roots of tolerant species presented a drop due to flooding. Only S. commersoniana presented a recovery in respiration after 60 days of flooding. The intolerant species S. terebinthifolius did not present alterations caused by flooding in its aerobic metabolism, whereas P. dubium, also intolerant, presented a drop in the absortion of O2 with two days of hypoxia, and recovery after 60 days. The liberation of CO2 in the tolerant species followed the same pattern of O2 absorption, with the exception of S. commersoniana, which presented a reduction in the liberation of CO2 after 60 days of flooding similar to what happened to P. dubium. In S. terebinthifolius there was no significant reduction with flooding. The difficulty in establishing a difference pattern in the respiratory metabolism of the species studied, concerning tolerance to flooding, emphasizes the complexity of tropical plant responses.


Brazilian Archives of Biology and Technology | 2007

Physiological aspects of sun and shade leaves of Lithraea molleoides (Vell.) Engl. (Anacardiaceae)

Jaqueline Dias; José Antonio Pimenta; Moacyr Eurípedes Medri; Maria Regina Torres Boeger; Claudinei Toledo de Freitas

O presente trabalho teve como objetivo avaliar de forma comparativa alguns parâmetros fisiologicos de folhas de sol e de sombra de um especime de L. molleoides. Esta especie e conhecida popularmente como aroeira-branca. As folhas da porcao superior periferica, denominadas folhas de sol, apresentaram igual taxa fotossintetica, menores teores de clorofilas (a, b e totais), mesma razao clorofila a/ clorofila b, menor taxa transpiratoria, mesma condutância estomatica e concentracao intercelular de CO2 em relacao as folhas da porcao inferior interna, denominadas folhas de sombra. A concentracao de nutrientes, excetuando Ca e Mg, foi igual em folhas de sol e de sombra. As respostas dos parâmetros fisiologicos avaliados indicam que as folhas de sombra, apesar de receberem menor intensidade luminosa, tem possibilidade de crescer e se desenvolver com a mesma capacidade das folhas de sol.


Acta Botanica Brasilica | 2011

Produção de serapilheira e ciclagem de nutrientes de um reflorestamento e de uma floresta estacional semidecidual no sul do Brasil

José Antonio Pimenta; Leopoldo Bopp Rossi; José Marcelo Domingues Torezan; Alba Lúcia Cavalheiro; Edmilson Bianchini

A producao, o conteudo de N, P, K, Ca e Mg, a transferencia de nutrientes e a taxa de decomposicao da serapilheira foram estudados em uma Floresta Estacional Semidecidual e em um reflorestamento situado adjacente a esta no Parque Estadual Mata dos Godoy, Estado do Parana, Brasil. A deposicao anual de serapilheira foi estimada em 8.212 kg.ha-1.ano-1 na floresta e 5.341 kg.ha-1.ano-1 no reflorestamento. A floresta apresentou nos dois meses apos a seca (setembro e outubro) maior deposicao. Nas duas areas a media anual da concentracao de macronutrientes em g.kg-1, obedeceu a mesma ordem na floresta Ca(31,85) > N(19,94) > K(7,14) > Mg(2,28) > P(0,217) e no reflorestamento Ca(23,02) > N(19,62) > K(7,67) > Mg(1,74) > P(0,302). No reflorestamento a transferencia de nutrientes variou mais durante o ano e a taxa de decomposicao foi menor.


Brazilian Archives of Biology and Technology | 2009

Morpho-anatomical and micromorphometrical evaluations in soybean genotypes during water stress.

Renata Stolf; Moacyr Eurípedes Medri; José Antonio Pimenta; Maria Regina Torres Boeger; Jaqueline Dias; Noélle Giacomini Lemos; Maria Cristina Neves de Oliveira; R. L. Brogin; Naoki Yamanaka; Norman Neumaier; J. R. B. Farias; Alexandre Lima Nepomuceno

In a greenhouse experiment, morpho-anatomical and micromorphometrical analyses of two soybean cultivars, MG/BR46 (Conquista) and BR16-tolerant and sensitive to drought, respectively-were used to study their water-deficit-tolerance strategies. Drought treatments were applied at reproductive stages from R2 to R7, where evaluations were conducted at 30 days and 45 days after stress started, respectively. The total length of Conquista plants (shoot + root) was greater than of BR16 plants. Pod dry weight was adversely affected due to the lack of moisture, decreasing productivity even of Conquista plants. Both the cultivars had normal development of root hairs; however, it was observed a decrease in the cortex:central cylinder ratio in BR16 stressed for 30 days, and they also showed similar leaflet thickness and stomata distribution. Differences in drought tolerance observed between the two cultivars seemed to be related to factors other than morphological traits since this species has a short lifecycle.


Brazilian Archives of Biology and Technology | 1998

Tolerância à inundação: aspectos da anatomia ecológica e do desenvolvimento de Sesbania virgata (Cav.) Pers. (Fabaceae)

Viviane M. Davanso-Fabro; Moacyr Eurípedes Medri; Edmilson Bianchini; José Antonio Pimenta

Twenty days seedlings of Sesbania virgata (Cav.) Pers. (Fabaceae) cultivated in green house were flooded by forty days. Flooded plants presented increasing of dry weight and lenght, evident cortical fissures and spongy cortical swelling on the stem basis and root, superficial roots on the soil and adventitious roots. It is possible that the morpho-anatomic plasticity presented by this specie is contribuiting for its hipoxic soils stablishment.

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Edmilson Bianchini

Venezuelan Institute for Scientific Research

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Moacyr Eurípedes Medri

Universidade Estadual de Londrina

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Paulo Souza Medri

Universidade Estadual de Londrina

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Talita Parpinelli Ferracin

Universidade Estadual de Londrina

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Diego Resende Rodrigues

Universidade Estadual de Londrina

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Halley Caixeta Oliveira

Universidade Estadual de Londrina

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Renata Stolf-Moreira

Universidade Estadual de Londrina

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Yves Rafael Bovolenta

Universidade Estadual de Londrina

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Cristiano Medri

University of East London

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