Physiological Changes In Seeds And Antioxidant Metabolism Of Lettuce Seedling Exposed To The Action Of Zanledeschia Aethiopica Spreng. Leaf Extract [alteracoes Fisiologicas Em Sementes E Metabolismo Antioxidativo De Plantulas De Alface Expostas A Acao Do Extrato Das Folhas De Zantedeschia Aethiopica Spreng]

This work aimed to evaluate the influence of different concentrations of Zantedeschia aethiopica Spreng. extract on the physiological performance of the seed and on the response of the antioxidant metabolism of lettuce seedlings. The treatments consisted of leaves extracts from Z. aethiopica at concentrations of 0, 6, 12, 25 and 50%. Germination, first germination count, germination speed and index, length of shoot and radicle, seedling total dry mass, chlorophyll content, activity of superoxide dismutase, catalase and ascorbarte peroxidase enzymes, lipid peroxidation, hydrogen peroxide quantification and seedling emergence, length of organs, and total dry mass of seedlings were evaluated. The percentage of germination, radícuthe length of the shoot and radicle of seedlings and the total dry mass of seedlings grown in the greenhouse were reduced as the concentration of the extract increased. There were increases of electrical conductivity, of superoxide dismutase, catalase and ascorbate peroxidadase enzymes and the amount of hydrogen peroxide and lipid peroxidation in seedlings with increasing extract concentration. The extract reduced the physiological quality of lettuce seeds and induced an increased production of hydrogen peroxide in seedlings, which increased the activity of antioxidant enzymes that were not effective in tissue detoxification, resulting in cellular damage and increased numbers of abnormal seedlings.3711845851Alves, S.M., Santos, L.S., Natureza química dos agentes alelopáticos (2002) Alelopatia: Princípios Básicos E Aspectos Gerais, pp. 25-47. , Em Souza Filho APS, Alves SM (Eds.), Embrapa Amazônia Oriental. Belém, BrasilArnon, D.I., Copper enzymes in isolated chloroplasts (1949) Plant Physiol, 24, pp. 1-15. , Polyphenoloxidase in Beta vulgarisAzevedo, R.A., Alas, R.M., Smith, R.J., Lea, P.J., Response of antioxidant enzymes to transfer from elevated carbon dioxide to air and ozone fumigation, in the leaves and roots of wild-type and a catalase-deficient mutant of barley (1998) Physiologia Plantarum, 104 (2), pp. 280-292. , DOI 10.1034/j.1399-3054.1998.1040217.xBarreiros, A.L.B.S., David, J.M., David, J.P., Oxidative stress: Relations between the formation of reactive species and the organism's defense (2006) Quimica Nova, 29 (1), pp. 113-123. , http://www.scielo.br/pdf/qn/v29n1/27866.pdfBasile, A., Sorbo, S., Lopez-Saez, J.A., Cobianchi, R.C., Effects of seven pure flavonoids from mosses on germination and growth of Tortula muralis HEDW. (Bryophyta) and Raphanus sativus l. (Magnoliophyta) (2003) Phytochemistry, 62 (7), pp. 1145-1151. , DOI 10.1016/S0031-9422(02)00659-3, PII S0031942202006593Regras Para Análise de Sementes, p. 398. , Brasil (2009), SNAD/CLAV. Ministério da Agricultura e Reforma Agrária. Brasília, BrasilCakmak, I., Horst, W.J., Effect of aluminium on lipid peroxidation, superoxide dismutase, catalase, and peroxidase activities in root tips of soybean (Glycine max) (1991) Physiol. Plant, 83, pp. 463-468Chou, C.H., Roles of allelopathy in plant biodiversity and sustainable agriculture (1999) Crit. Rev. Plant Sci, 18, pp. 609-630Chou, C.H., Introduction to allelopathy (2006) Allelopathy: A Physiological Process with Ecological Implications, p. 637. , Em Reigosa MJ, Pedrol N, González L (Eds), Springer. Dordrecht, HolandaChung, I.M., Ahn, J.K., Yun, S.J., Assessment of allelopathic potential of barnyard grass (Echinochloa crus-galli) on rice (Oryza sativa L.) cultivars (2001) Crop Protection, 20 (10), pp. 921-928. , DOI 10.1016/S0261-2194(01)00046-1, PII S0261219401000461Coelho, M.F.B., Maia, S.S.S., Oliveira, A.K., Diógenes, F.E.P., Atividade alelopática de extrato de sementes de juazeiro (2011) Hort. Brás, 29, pp. 108-111Ducca, F., Zonetti, P.C., Efeito alelopático do extrato aquoso da aveia preta (Avena strigosa Schreb) na germinação e desenvolvimento de soja (Glycine max L. Merril) (2008) Rev. Agroneg. Meio Amb, 1, pp. 101-109Ferreira, A.G., Aquila, M.E.A., Alelopatia: Uma área emergente da ecofisiologia (2000) Rev. Brás. Fisiol. Veg, 12, pp. 175-204Giannopolitis, C.N., Ries, S.K., Superoxide dismutase. I. Occurrence in higher plants (1997) Plant Physiol, 59, pp. 309-314Greca, M.D., Ferrara, M., Fiorentino, A., Monaco, P., Previtera, L., Antialgal compounds from Zantedeschia aethiopica (1998) Phytochemistry, 49 (5), pp. 1299-1304. , DOI 10.1016/S0031-9422(98)00092-2, PII S0031942298000922Han, C., Pan, K., Wu, N., Wang, J., Li, W., Allelopathic effect of ginger on seed germination and seedling growth of soybean anchive (2008) Sci. Hort, 116, pp. 330-336Hong, N.H., Xuan, T.D., Eiji, T., Khanh, T.D., Paddy weed control by higher plants from Southeast Asia (2004) Crop Protection, 23 (3), pp. 255-261. , DOI 10.1016/j.cropro.2003.08.008Krzyzanowski, F.C., França-Neto, J.B., Henning, A.A., Relato dos testes de vigor disponíveis para grandes culturas (1991) Inf. ABRATES, 1, pp. 15-50Lichtenthaler, H.K., Chlorophylls and carotenoids: Pigments of photosynthetic biomembranes (1987) Meth. Enzymol, 148, pp. 350-382Lima, C.P., Cunico, M.M., Trevisan, R.R., Philippsen, A.F., Miguel, O.G., Miguel, M.D., Efeito alelopático e toxicidade frente à Artemia salina Leach dos extratos do fruto de Euterpe edulis Martius (2011) Acta Bot. Brás, 25, pp. 331-336Lima, J.D., Moraes, W.S., Potencial alelopático de Ipomoea fiulosa sobre a germinação de alface e tomate (2008) Acta Sci. Agron, 30, pp. 409-413Macias, F.A., Molinillo, J.M.G., Varela, R.M., Galindo, J.C.G., Allelopathy - A natural alternative for weed control (2007) Pest Management Science, 63 (4), pp. 327-348. , DOI 10.1002/ps.1342Marenco, R.A., Lopes, N.F., (2007) Fisiologia Vegetal: Fotossíntese, Respiração, Relações Hídricas e Nutrição Mineral, p. 451. , 2 ed. UFV. Viçosa, BrasilMatés, J.M., Effects of antioxidant enzymes in the molecular control of reactive oxygen species toxicology (2000) Toxicology, 153, pp. 83-104Muniz, F.R., Cardoso, M.D.G., Von Pinho, E.V.R., Vilela, M., Physiological quality of corn, bean, soybean and lettuce seeds in the presence of sedge extract (2007) Revista Brasileira de Sementes, 29 (2), pp. 195-204. , http://www.scielo.br/pdf/rbs/v29n2/v29n2a26.pdf, DOI 10.1590/S0101-31222007000200026Nakagawa, J., Testes de vigor baseados na avaliação de plântulas (1994) Testes de Vigor Em Sementes, pp. 49-85. , Em Vieira RD, Carvalho M (Eds.), FUNEP. Jaboticabal, BrasilNakano, Y., Asada, K., Hydrogen peroxide is scavenged by ascobate-specific peroxidase in spinach chloroplasts (1981) Plant Cell Physiol, 22, pp. 867-880Pires, N.D.M., Souza, I.R.P., Prates, H.T., De Faria, T.C.L., Pereira Filho, I.A., Magalhaes, E.P.C., Effect of leucaena aqueous extract on the development, mitotic index and peroxidase activity in maize seedlings (2001) Revista Brasileira de Fisiologia Vegetal, 13 (1), pp. 55-65Politycka, B., Gmerek, J., Effect of ferulic and p-coumaric acidson the activity of hydrolytic enzymes and growth of radicals in germinating seeds of cucumber and pea (2008) Allelopathy J, 21, pp. 227-238Rosa, S.D.V.F., Rezende, E.V.R.V.P., Vieira, E.S.N., Veiga, R.D., Veiga, A.D., Enzimas removedoras de radicais livres e proteínas lea associadas à tolerância de sementes milho à alta temperatura de secagem (2005) Rev. Brás. Sementes, 27, pp. 91-101Rice, E.L., (1984) Allelopathy, p. 422. , 2 ed. Academic Press: Nova York, EEUURizvi, S.J.H., Haque, H., Singh, V.K., Rizvi, V., A discipline called allelopathy (1992) Allelopathy: Basic and Applied Aspects, p. 504. , Em Rizvi SJH, Rizvi V (Eds.), Chapman & Hall. Londra, RUSilva, V.S., Cândido, A.C.S., Muller, C., Laura, V.A., Faccenda, O., Simionatto, E., Hess, S.C., Peres, M.T.L.P., Potencial fitotóxico de Dicranopteris flexuosa (Schrad.) Underw. (Gleicheniaceae) (2011) Acta Bot. Brás, 25, pp. 95-104Sinha, S., Saxena, R., Effect of iron on lipid peroxidation, and enzymatic and non-enzymatic antioxidants and bacoside-A content in medicinal plant Bacopa monnieri L (2006) Chemosphere, 62 (8), pp. 1340-1350. , DOI 10.1016/j.chemosphere.2005.07.030, PII S0045653505009409Singh, A., Singh, D., Singh, N.B., Allelochemical stress produced by aqueous leachate of nicotiana plumbaginifolia Viv (2009) Plant Growth Regul, 58, pp. 163-171Streit, M.N., Canterle, L.P., Canto, M.W., Hecktheuer, L.H.H., As clorofilas (2005) Ciênc. Rural, 35, pp. 748-755Velikova, V., Yordanov, I., Edreva, A., Oxidative stress and some antioxidant systems in acid rain-treated bean plants (2000) Plant Sci, 151, pp. 59-66Yu, J.Q., Ye, S.F., Zhang, M.F., Hu, W.H., Effects of root exudates and aqueous root extracts of cucumber (Cucumis sativus) and allelochemicals, on photosynthesis and antioxidant enzymes in cucumber (2003) Biochemical Systematics and Ecology, 31 (2), pp. 129-139. , DOI 10.1016/S0305-1978(02)00150-3Zhang, D., Zhang, J., Yang, W., Wu, F., Potential allelopathic effect of eucalypus grandis across a range of plantation ages (2010) Ecol. Res, 25, pp. 13-2

Análise de crescimento e partição de assimilados em plantas de maria-pretinha submetidas a níveis de sombreamento Growth analysis and partitioning of assimilates in mary-nightshade plants submitted to shading levels

A espécie Solanum americanum (maria-pretinha) é considerada planta daninha; por possuir elevada habilidade competitiva e agressividade, ela reduz a produtividade dos cultivos. O trabalho foi conduzido em casa de vegetação e objetivou analisar o crescimento e a partição de assimilados em plantas de maria-pretinha submetidas a três níveis de sombreamento. As plantas foram coletadas em intervalos regulares de sete dias após o transplante até o final do ciclo, sendo determinada a massa seca e a área foliar. A partir dos dados primários, foi aplicada a análise de crescimento, sendo calculados a massa seca total (Wt), as taxas de produção de matéria seca (Ct), crescimento relativo (Rw) e assimilatória líquída (Ea), o índice de área foliar (L), as razões de área foliar (Fa) e massa foliar (Fw), a área foliar específica (Sa), a partição de matéria seca entre órgãos e o número de frutos. Plantas de maria-pretinha cresceram e se desenvolveram melhor sob condição intermediária de luz (65%), em que atingiram maior Wt, Ct, L, Fa, matéria seca de caule, matéria seca de fruto e maior número de frutos, enquanto a luz plena e a redução da luminosidade em nível acentuado, de maneira mais marcante, afetaram negativamente o crescimento e o desenvolvimento, o que possivelmente pode influenciar a habilidade competitiva da maria-pretinha.<br>The species Solanum americanum (mary-nightshade) is considered a weed whose highly competitive ability and aggressiveness reduce crop productivity. This work was conducted under greenhouse conditions aiming to analyze the growth and partitioning of assimilates in mary-nightshade plants subjected to three levels of shading. The plants were collected at regular intervals of seven days after transplantation until the end of the cycle, with dry mass and leaf area being determined. Based on primary data , growth analysis was carried out to calculate total dry matter production (Wt), dry matter production rates (Ct), relative growth (R-w), net assimilation (Ea), leaf area index (L), relative growth of leaf area and ratios of leaf area (Fa) and leaf mass (Fw), specific leaf area (Sa) and dry matter partitioning between organs. Mary-nightshade plants showed a better growth and development under intermediate light conditions (35% shade), reaching higher Wt, Ct, L, Fa, stem dry matter, fruit dry matter and number of fruit. Full light and reduction of light at a more accentuated level had a negative effect on growth and development, a fact that may influence the competitive ability of these plants