Reserve mobilisation in mesquite (Prosopis juliflora) seed (Leguminosae) |
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Authors: | Maria I Gallão Ícaro GP Vieira Francisca NP Mendes Alex SN de Souza Edy S de Brito |
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Affiliation: | 1. Departamento de Biologia, Universidade Federal do Ceará, Campus do Pici, CEP 60455 760, Fortaleza, CE, BrazilDepartamento de Biologia, Universidade Federal do Ceará, Campus do Pici, CEP 60455 760, Fortaleza, CE, Brazil.;2. Centro de Ciência e Tecnologia, Universidade Estadual do Ceará, Campus do Itaperi, CEP 60780 094, Fortaleza, CE, Brazil;3. Parque de Desenvolvimento Tecnológico (PADETEC), Campus do Pici, CEP 60455 970, Fortaleza, CE, Brazil;4. Embrapa Agroindústria Tropical, R Dra Sara Mesquita, 2270, Pici, CEP 60511 110, Fortaleza, CE, Brazil |
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Abstract: | The seeds of Prosopis juliflora (mesquite) have a water barrier composed of the palisade layer present in the seed tegument and galactomannans in the endosperm. Changes in the morphological and physiological states of seeds are usually accompanied by changes in their metabolism. The aim of this study was to detect and characterise the main reserves and their mobilisation during and following germination of P. juliflora seeds. Sections of seeds 0, 24, 48 and 72 h after the onset of the imbibing process were evaluated by light microscopy, and seed reserves were extracted and quantified. Polysaccharides were isolated and characterised by 1H nuclear magnetic resonance (NMR) spectroscopy. In mesquite seeds a well‐developed endosperm, consisting largely of the storage carbohydrate (galactomannans), lies between the seed coat and the cotyledons. Germination was complete after 24 h of imbibition. At this time, morphological changes were observed in stained protein bodies. Chemical analysis showed a decrease in protein levels until 48 h. After 48 h, globular structures were observed in the cotyledon cells, but after 72 h these grains were smaller and their content was reduced. Polarisation microscopy confirmed that this material was composed of starch grains. The 1H NMR spectrum of P. juliflora seeds showed that sucrose was used following germination. Apparently, sucrose is the transport sugar mobilised from reserve stocks for seedling growth. Parallel to endosperm galactomannan degradation, starch is produced transitorily in the cotyledon. Copyright © 2007 Society of Chemical Industry |
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Keywords: | Prosopis juliflora galactomannan mesquite Leguminosae |
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