Effects of ozone microbubble treatment on removal of residual pesticides and quality of persimmon leaves.

This study investigated the effects of ozone microbubble (OMCB) treatment on the removal of residual fenitrothion (FT) and benomyl pesticides from red and green persimmon leaves, and also the treatment effect on the leaf colours, physical properties and flavour. The continuous bubbling OMCB treatment was more effective than the non-bubbling OMCB treatments at reducing the FT and benomyl agricultural pesticide residues from both the red and green persimmon leaves. Moreover, the bubbling OMCB treatment had no effect on the colour and pulling strength of the leaves. These results indicate that the treatment by bubbling OMCB is an extremely effective method for removing the residues of FT and benomyl in persimmon leaves and has relatively little effect on leaf quality characteristics.

Identification of xyloglucan endotransglucosylase/hydrolase genes (XTHs) and their expression in persimmon fruit as influenced by 1-methylcyclopropene and gibberellic acid during storage at ambient temperature.

Xyloglucan endotransglucosylase/hydrolase (XTH) is thought to contribute to fruit softening by degrading xyloglucan that is a predominant hemicellulose in the cell wall. In this study, two full-length XTH genes (DKXTH1 and DKXTH2) were identified from 'Fupingjianshi' persimmon fruit, and the expression level of both XTH genes was investigated during softening for 18-24 d using RT-qPCR. Sequence analysis showed that DKXTH1 and DKXTH2 contained a putative open reading frame of 861 and 876 bp encoding polypeptides of 287 and 292 amino acid residues, respectively, which contained the conserved DEIDFEFLG motif of XTH, a potential N-linked glycosylation signal site. RT-qPCR analysis showed that DKXTH1 and DKXTH2 in untreated fruit had different expression patterns during fruit softening, in which maximum expression occurred on days 3 and 12 of ripening, respectively. 1-Methylcyclopropene (1-MCP) and gibberellic acid (GA(3)) treatments delayed the softening and ethylene peak of persimmon fruit, as well as suppressed the expression of both XTH genes, especially DKXTH1. These results indicated that the expression of both XTH genes might be ethylene dependent action, and closely related to softening of persimmon in the early (DKXTH1) and later (DKXTH2) ripening stages.