Role of cell wall polysaccharides in water distribution during seed imbibition of Hymenaea courbaril L.

Autor(es)

Grandis, A. ; Santos, H. P. ; Tonini, P. P. ; Salles, I. S. ; Peres, A. S. C. ; Carpita, N. C. ; Buckeridge, M. S.

• Tipo de documento: Artigo Científico
• Fonte: Plant Biology; v. 26, n. 6, p. 13-pg., 2024-07-05.

Resumo

Seed water imbibition is critical to seedling establishment in tropical forests. The seeds of the neotropical tree Hymenaea courbaril have no oil reserves and have been used as a model to study storage cell wall polysaccharide (xyloglucan - XyG) mobilization. We studied pathways of water imbibition in Hymenaea seeds. To understand seed features, we performed carbohydrate analysis and scanning electron microscopy. We found that the seed coat comprises a palisade of lignified cells, below which are several cell layers with cell walls rich in pectin. The cotyledons are composed mainly of storage XyG. From a single point of scarification on the seed surface, we followed water imbibition pathways in the entire seed using fluorescent dye and NMRi spectroscopy. We constructed composites of cellulose with Hymenaea pectin or XyG. In vitro experiments demonstrated cell wall polymer capacity to imbibe water, with XyG imbibition much slower than the pectin-rich layer of the seed coat.<br /> We found that water rapidly crosses the lignified layer and reaches the pectin-rich palisade layer so that water rapidly surrounds the whole seed. Water travels very slowly in cotyledons (most of the seed mass) because it is imbibed in the XyG-rich storage walls. However, there are channels among the cotyledon cells through which water travels rapidly, so the primary cell walls containing pectins will retain water around each storage cell.<br /> The different seed tissue dynamic interactions between water and wall polysaccharides (pectins and XyG) are essential to determining water distribution and preparing the seed for germination. (AU)

• Processo FAPESP: 19/13936-0 - O papel do xiloglucano na determinação da arquitetura da parede celular de cana de açúcar
• Beneficiário: Adriana Grandis
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 14/50884-5 - INCT 2014: Instituto Nacional de Ciência e Tecnologia do Bioetanol
• Beneficiário: Marcos Silveira Buckeridge
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 98/05124-8 - Conservação e uso sustentável da biodiversidade vegetal do Cerrado e da Mata Atlântica: o armazenamento de carboidratos e seu papel na adaptação e manutenção de plantas em seu habitat natural
• Beneficiário: Marcos Silveira Buckeridge
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático