title: Specific lignin accumulation in granulated juice sacs of Citrus maxima.
abstract: Juice sac granulation occurring in pummelo fruits [Citrus maxima (Burm.) Merr.] is an undesirable trait, and the underlying mechanism remains unresolved. Previous studies have shown that lignin metabolism is closely associated with the process of juice sac granulation. Here, a method suitable for lignin isolation from pummelo tissues is established. Acetylated lignins from different pummelo tissues and cultivars were analyzed by HSQC NMR. The results showed that lignins in granulated juice sacs were characterized by an extremely high abundance of guaiacyl units (91.13-96.82%), in contrast to lignins from other tissues, including leaves, stems, and segment membranes. The abnormally accumulated lignins in granulated juice sacs were specific and mainly polymerized from coniferyl alcohol. No significant difference was found in lignin types among various cultivars. These findings indicated that the mechanism of juice sac granulation might be similar among various cultivars, although very different degrees of juice sac granulation can be observed.
authors.affiliation: College of Horticulture and Institute of Storage Science and Technology of Horticultural Products, Fujian Agriculture and Forestry University , Fuzhou 350002, China.
authors.forename: Jia-Ling
authors.initials: JL
authors.lastname: Wu
authors.forename: Teng-Fei
authors.initials: TF
authors.lastname: Pan
authors.forename: Zhi-Xiong
authors.initials: ZX
authors.lastname: Guo
authors.forename: Dong-Ming
authors.initials: DM
authors.lastname: Pan
mesh_terms: D001628:Beverages / Q000032:analysis*; D002957:Citrus / Q000737:chemistry*; D061353:Food Storage; D005638:Fruit / Q000737:chemistry; D008031:Lignin / Q000737:chemistry*; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D058105:Polymerization
chemical_list: D010636:Phenols; D010936:Plant Extracts; D008031:Lignin; C010559:coniferyl alcohol
keywords: heteronuclear single-quantum coherence; juice sac granulation; nuclear magnetic resonance; pummelo fruits; ultraviolet−visible spectroscopy