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| Amaral,Lourdes Isabel Velho do; Santos,Henrique P.; Rossatto,Davi Rodrigo; Buckeridge,Marcos Silveira. |
| The cotyledons of Hymenaea courbaril store large amounts of xyloglucan, a cell wall polysaccharide that is believed to serve as storage for the period of seedling establishment. During storage mobilisation, xyloglucan seems to be degraded by a continuous process that starts right after radicle protrusion and follows up to the establishment of photosynthesis. Here we show evidence that events related to the hydrolases activities and production (α-xylosidase, β-galactosidase, β-glucosidase and xyloglucan endo-β-transglucosilase) as well as auxin, showed changes that follow the diurnal cycle. The period of higher hydrolases activities was between 6pm and 6am, which is out of phase with photosynthesis. Among the enzymes, α-xilosidase seems to be more important... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Enzyme activity; IAA; Α-xylosidase; XTH; Xyloglucan. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042012000400008 |
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| Aidar,M.P.M.; Martinez,C.A.; Costa,A.C.; Costa,P.M.F.; Dietrich,S.M.C.; Buckeridge,M.S.. |
| Plants grown in elevated CO2 environments may exhibit photosynthetic acclimation or down regulation, which is characterised by reduced rates of photosynthesis. In most cases of CO2-induced photosynthetic acclimation, the reduced rates of photosynthesis were still higher than those detected in plants growing at ambient CO2 concentrations. In this work we present a study on the behaviour of seedlings of Hymenaea courbaril, a late secondary/climax species that is one of the most important trees in mature tropical forests of the Americas. After germination, the seedling of H. courbaril increases its rate of growth due to the mobilisation of massive amounts of a storage cell wall polysaccharide (xyloglucan) from its cotyledons. In our experiments, germinated... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Photosynthesis; CO2 enrichment; Hymenaea courbaril; Storage mobilisation; Root:shoot ratio; Seedling growth; Cotyledons; Open top chamber; Xyloglucan; Biodiversity. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032002000100008 |
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| Bhalekar,Mangesh; Sonawane,Savita; Shimpi,Shamkant. |
| The aim of this study was to improve the mucoadhesive potential of xyloglucan polymer by the covalent attachment of cysteine as thiol moiety. The parent polymer xyloglucan was chemically modified by introducing sulphydryl bearing compound L-cysteine HCl. Different batches of xyloglucan-cysteine conjugates were prepared at varying reaction pH (2-6) and evaluated for optimum thiol incorporation, disulphide group content, swelling behavior, rheological properties and mucoadhesive properties. The obtained conjugates characterized in vitro by quantification of immobilized thiol groups; showed maximum thiol incorporation on xyloglucan (7.67 ± 0.14 %) at pH 5. The disulphide group content was found maximum (2.83 ± 0.12) at pH 6. The water uptake at end of 4 h was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mucoadhesion; Thiomer; Xyloglucan; L-cysteine HCl. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502013000200010 |
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