Sodium hydrosulfide delays the softening of fig fruit during cold storage

Fig fruits are rich in nutrients, but their rapid softening limits storage life. In this experiment, fig fruits were treated with 1.5 mmol L (-1) NaHS (a H2S donor) and 15 mu mol L (-1) hypotaurine (HT, a H2S scavenger), respectively, to evaluate the efficacy of H2S on maintaining the storage life of fig fruits. Changes in firmness, cell wall structure, cell wall polysaccharides contents, the activities of cell wall-degrading enzymes, and the expression of genes related to the cell wall metabolism of fig fruits were studied. The results showed that NaHS at 1.5 mmol L (-1) delayed the disruption of cell wall structure and maintained high protopectin, cellulose, and hemicellulose contents but a low water-soluble pectin content in fig fruits compared with the controls. NaHS inhibited the activities of polygalacturonase (PG), pectinesterase (PME), beta-galactosidase (beta-Gal), and cellulase (Cx) and down-regulated the expression levels of their corresponding genes (fcPG, fcPME, fc beta-Gal, and fcCx) in fig fruits during storage. The opposite results were found in fig fruits treated with HT. These results confirm that NaHS at 1.5 mmol L (-1) delayed the softening of harvested fig fruits by inhibiting cell wall polysaccharides' degradation.