Mafra Isabel, Lanza Barbara, Reis Ana, Marsilio Vincenzo, Campestre Cristina, De Angelis Mario, Coimbra Manuel A.
Departamento de Química, Universidade de Aveiro, P-3810-193 Aveiro, Portugal; Istituto Sperimentale per la Elaiotecnica, Contrada Fonte Umano n.37, Città S. Angelo (PE), I-65013 Italy.
Physiol Plant. 2001 Apr;111(4):439-447. doi: 10.1034/j.1399-3054.2001.1110403.x.
Olive fruits at the green, cherry and black stages were used to investigate the structural and microstructural changes in tissues during ripening. Scanning electron microscopy (SEM) tissue fracture of green olives resulted in cell wall breakage of epicarp and mesocarp cells. Tissue fracture resulted in fewer broken cells in cherry than in green olives and even less in black olive tissues. Cell separation occurred in the middle lamella region in some of the cells of the cherry fruit and in most of the black olive cells. Solubilization and loss of pectic polysaccharides, mainly the arabinan moiety, and glucuronoxylans occurred in the green to cherry stages. The pulp cell wall constituent polysaccharides, pectic polysaccharides, cellulose, glucuronoxylans and xyloglucans, were degraded and/or solubilized at the cherry to black ripening stages. The resultant depolymerization of the pectic polymers, especially those of the middle lamella region, was consistent with the progressive cell separation at the different ripening stages by SEM. This showed that partial solubilization of pectic, hemicellulosic and cellulosic polysaccharides within the cell wall matrix weakened the cell wall structures, preventing the breaking of cells when the tissues were fractured.
研究人员使用绿色、樱桃色和黑色阶段的橄榄果实来探究成熟过程中组织的结构和微观结构变化。绿色橄榄的扫描电子显微镜（SEM）组织断裂导致外果皮和中果皮细胞的细胞壁破裂。组织断裂导致樱桃色橄榄中破裂的细胞比绿色橄榄少，黑色橄榄组织中破裂的细胞更少。在樱桃果实的一些细胞和大多数黑色橄榄细胞的中层区域发生了细胞分离。从绿色到樱桃色阶段，主要是阿拉伯聚糖部分的果胶多糖以及葡糖醛酸木聚糖发生了溶解和损失。果肉细胞壁组成多糖，即果胶多糖、纤维素、葡糖醛酸木聚糖和木葡聚糖，在从樱桃色到黑色成熟阶段发生了降解和/或溶解。果胶聚合物，尤其是中层区域的果胶聚合物的解聚，与扫描电子显微镜观察到的不同成熟阶段的细胞逐渐分离一致。这表明细胞壁基质内果胶、半纤维素和纤维素多糖的部分溶解削弱了细胞壁结构，从而在组织断裂时防止细胞破裂。
