Decreased deposition and increased swelling of cell walls contribute to increased cracking susceptibility of developing sweet cherry fruit

Abstract

Main conclusion During fruit development, cell wall deposition rate decreases and cell wall swelling increases. The cell wall swelling pressure is very low relative to the fruit’s highly negative osmotic potential. Abstract Rain cracking of sweet cherry fruit is preceded by the swelling of the cell walls. Cell wall swelling decreases both the cell: cell adhesion and the cell wall fracture force. Rain cracking susceptibility increases during fruit development. The objectives were to relate developmental changes in cell wall swelling to compositional changes taking place in the cell wall. During fruit development, total mass of cell wall, of pectins and of hemicelluloses increases, but total mass of cellulose remains constant. The mass of these cell wall fractions increases at a lower rate than the fruit fresh mass—particularly during stage II and early stage III. During stage III, on a whole-fruit basis, the HCl-soluble pectin fraction, followed by the water-soluble pectin fraction, the NaOH-soluble pectin fraction and the oxalate-soluble pectin fraction all increase. At maturity, just the HCl-soluble pectin decreases. Cell wall swelling increases during stages I and II of fruit development, with little change thereafter. This was indexed by light microscopy of skin sections following turgor release, and by determinations of the swelling capacity, water holding capacity and water retention capacity. The increase in cell wall swelling during development was due primarily to increases in NaOH-soluble pectins. The in vitro swelling of cell wall extracts depends on the applied pressure. The swelling pressure of the alcohol-insoluble residue is low throughout development and surprisingly similar across different cell wall fractions. Thus, swelling pressure does not contribute significantly to fruit water potential.

Methods for quality evaluation of sweet cherry

“…In sweet cherries, cracking can be divided into macro‐cracks (detectable by visual inspection) and micro‐cracks (undetectable by visual inspection) 67,96 . The economic impact of macro‐cracks is much higher than that of micro‐cracks because fruits with macro‐cracks are not marketable and are not even worth harvesting 97 …”

“…67,96 The economic impact of macro-cracks is much higher than that of micro-cracks because fruits with macrocracks are not marketable and are not even worth harvesting. 97 Macro-cracks may occur in distinct regions of the fruit, namely in the cheeks (side cracks), in the stylar scar region (apical end) or in the stem cavity region. 67 Most studies report that cracking or splitting is affected by environmental conditions, which can be caused by excessive rainfall before and during harvest.…”

Pectate Lyase Gene VvPL1 Plays a Role in Fruit Cracking of Table Grapes

“…During fruit ripening, the disassembly, modification, and composition of the cell wall components are regulated by a range of enzymes and proteins, including polygalacturonase (PG), expansin (EXP), pectinmethylesterase (PME), pectate lyase (PL), β-galactosidase (β-Gal), cellulase (Cx), xyloglucan endotransglycosylase (XET), α- l -arabinofuranosidase (AFase), etc . During fruit ripening, changes and degradation of the cell wall polysaccharide components lead to cell separation and swelling of the cell wall, resulting in fruit softening and texture changes, , and in the weakening process of the cell wall structure, fruit susceptibility to cracking also increases. , Thus, the differences in the cell wall metabolism between varieties could be an important factor in determining the fruit tendency to crack. However, there are few comprehensive studies on the relationship between grape berry cracking and cell wall metabolism.…”

Acceleration of Aril Cracking by Ethylene in Torreya grandis During Nut Maturation

“…Pericarp softening is an undesirable feature during the fruit cracking process, resulting in a loss of firmness, which is mainly caused by changes in cell wall structure and composition, such as cellulose, hemicelluloses, and pectin ( Brummell and Harpster, 2001 ; Brummell, 2006 ; Bennett and Labavitch, 2008 ). Previous studies showed that fruit cracking was accompanied by changes in cellular wall polysaccharide content, especially a continuous increase in water-soluble pectin (WSP) arising from chelator soluble pectin (CSP), sodium carbonate-soluble pectin (SSP), and hemicellulose ( Chen et al, 2016 ; Jiang F. et al, 2019 ; Schumann et al, 2020 ). During ripening, several hydrolytic enzymes and proteins located at the cell wall, including pectin methylesterase (PME), polygalacturonase (PG), pectate lyases (PL), β-galactosidase (β-gal), β-glucosidase (β-Glu), and expansin protein (EXP), cooperatively disassemble wall polysaccharide networks, thereby contributing to the softening and cracking of fruit ( Carpita et al, 2001 ; Marin-Rodriguez, 2002 ; Ruiz-May and Rose, 2013 ).…”