Work

Dynamic accumulation patterns of ABA, ROS and cell wall materials in the peel and pulp of ‘Nanfeng’ tangerine (Citrus reticulata Blanco) affected by puffing disorder

Year: 2025

Type: article

Abstract: Puffiness is a common physiological disorder in loose-skinned citrus fruit characterized by peel puffing and segment drying, which may be associated with senescence and the cell wall remodeling. This study aimed to explore the physiological and biochemical basis of this disorder by examining the dynamics of abscisic acid (ABA), reactive oxygen species, oxidative stress markers, antioxidant defence systems, and cell wall metabolism in both peel and pulp tissues of ‘Nanfeng’ tangerine (Citrus reticulata) upon puffiness. As the puffing degree increased, though ABA levels rose significantly in the peel while decreased in the pulp; concurrently, both hydrogen peroxide and malondialdehyde contents declined in the peel but increased in the pulp. Antioxidant defence system (SOD, CAT, APX, POD, PPO, AsA, total phenol and flavonoids), as well as DPPH radical scavenging rate and FRAP were 2.26-10.47 folds higher in the peel relative to the pulp. These results indicated a tardily senescent progress in the peel but accelerated senescent progress in the pulp. Cell wall components including lignin, cellulose, hemicellulose, propectin and pectin significantly decreased in the puffed peel and negatively correlated with puffing degree, while they (except for propectin) increased in the pulp, which suggest a potential breakdown of peel cell wall and a synthesis of pulp cell wall. Accordingly, gene expression and activity of phenylalanine ammonia lyase, key enzyme for lignin biosynthesis, decreased in the peel while increased in the pulp. Activities of pectin and cellulose metabolism related enzymes PME, β-Gal, and Cel increased, and PG decreased in both peel and pulp. These findings highlight the asynchronous senescence of the peel and pulp leads to the cell wall metabolism of the peel and pulp moving respectively towards degradation and synthesis, resulting in reduced peel firmness due to tissue loosening, increased pulp hardness accompanied by drying and shrinkage, and ultimately separation between the peel and pulp creating air-filled spaces.

Source: Scientia Horticulturae

DOI: 10.1016/j.scienta.2025.114500