Diurnal Variation In The Activity Of Enzymes Of Sucrose Catabolism In Hymenaea Courbaril L. Plantlets During Storage Xyloglucan Mobilization [variação Ao Longo Do Dia Da Atividade De Enzimas Do Catabolismo De Sacarose Em Plântulas De Hymenaea Courbaril L. Durante A Mobilização Do Xiloglucano De Reserva]

Seeds of Hymenaea courbaril L. have a storage polysaccharide that is mobilized after germination, when the first leaf is already photosynthetic. During reserve mobilization, the seedling has to coordinate two carbohydrate sources: photosynthesis and storage mobilisation. Both use sucrose to export carbon. To understand the allocation of carbon resources in the seedling, therefore, it is essential to study the catabolism of sucrose in the organs. In the present work, the low molecular weight carbohydrates were analyzed, as well as the activity of sucrose synthase and of the three isoforms of invertase in organs of Hymenaea courbaril L. seedlings along a day. The analysis was made each 6 hours, with an extra analysis at 2 am. Each enzyme had a characteristic variation pattern along the day, suggesting distinct and independent functions for each organ. The carbohydrate analysis showed higher concentration of sucrose in the sink-organs, while the cotyledons had high concentration of free monosaccharides. The existence of isoforms with distinct properties and cellular distribution varying in independent ways along the day suggests that these isoforms may have distinct physiological functions in the plant.321143153Amaral, L.M.V., (2005) Metabolismo de carboidratos estruturais e de reserva em cotilédones de Hymenaea courbaril L. (Jatobá), , Tese de doutorado, Universidade de São Paulo, São PauloBarriga, M.L., (2003) Fitomonitoração e modelagem de fotossíntese em jatobá (Hymenaea courbaril L.) com redes neurais artificiais, , Tese de doutorado, Universidade de São Paulo, São PauloBlässing, O.E., Gibon, Y., Günther, M., Höhne, M., Morcuende, R., Osuna, D., Thimm, O., Stitt, M., Sugars and circadian regulation make major contributions to the global regulation of diurnal gene expression in Arabidopsis (2005) The Plant Cell, 17, pp. 3257-3281Buckeridge, M.S., Dietrich, S.M.C., Galactomannan from Brazilian legume seeds (1990) Revista Brasileira de Botânica, 13, pp. 109-112Chen, Y.C., Chourey, P.S., Spatial and temporal expression of the two sucrose synthase genes in maize: Immunohistological evidence (1989) Theoretical and Applied Genetics, 78, pp. 5553-559Dubois, M., Gilles, A., Hamilton, J.K., Rerbers, P.A., Smith, F., Colorimetric method for determination of sugars and related substances (1956) Analitical Chemistry, 28, pp. 350-355Duncan, K.A., Hardin, S.C., Huber, S.C., The three maize sucrose synthase isoforms differ in distribution, localization, and phosphorylation (2006) Plant Cell Physiology, 47, pp. 959-971Farrar, J., Pollock, C., Gallagher, J., Sucrose and the integration of metabolism in vascular plants (2000) Plant Science, 154, pp. 1-11Gibson, S.I., Control of plant development and gene expression by sugar signaling (2005) Current Opinion in Plant Biology, 8, pp. 93-102Jauh, G.Y., Phillips, T.E., Rogers, J.C., Tonoplast intrinsic protein isoforms as markers for vacuolar functions (1999) The Plant Cell, 11, pp. 1867-1882Lee, Y., Langenheim, J.H., (1975) Systematics of the Genus Hymenaea L. (Leguminosae, Caesalpinioideae, Detarieae), 69. , University of California Publications in Botany, BerkeleyNguyen-Quoc, B., Foyer, C.H., A role for futile cycles involving invertase and sucrose synthase in sucrose metabolism of tomato fruit (2001) Journal of Experimental Botany, 52, pp. 881-889Rolland, F., Moore, B., Sheen, J., Sugar sensing and signalling in plants (2002) The Plant Cell (suplement), pp. 185-205Santos, H.P., Buckeridge, M.S., The role of the storage carbon of cotiledons in the establishment of seedlings of Hymenaea courbaril under different light conditions (2004) Annals of Botany, 94, pp. 819-830Sturm, A., Invertases. Primary structures, functions, and roles in plant development and sucrose partitioning (1999) Plant Physiology, 121, pp. 1-7Sturm, A., Tang, G.Q., The sucrose-cleaving enzymes of plants are crucial for development, growth and carbon partitioning (1999) Trends in Plant Science, 4, pp. 401-407Sung, S.S., Xu, D.P., Black, C.C., Identification of actively filling sucrose sinks (1989) Plant Physiology, 89, pp. 1117-1121Taiz, L., Zeiger, E., Photosynthesis: Carbon reactions (2003) Plant Physiology, pp. 145-168. , L. Taiz & E. Zeiger, eds., Sinauer Associates, SunderlandTiné, M.A.S., Cortelazzo, A.L., Buckeridge, M.S., Xyloglucan mobilisation in cotyledons of developing plantlets of Hymenaea courbaril L. (Leguminosae-Caesalpinoideae) (2000) Plant Science, 154, pp. 117-126Wang, F., Sanz, A., Brenner, M.L., Smith, A., Sucrose synthase, starch accumulation, and tomato fruit sink strength (1993) Plant Phisiology, 101, pp. 321-327Winter, H., Huber, S.C., Regulation of sucrose metabolism in higher plants: Localization and regulation of activity of key enzymes (2000) Critical Reviews in Plant Sciences, 19, pp. 31-6