S23 - Session P3 - Peroxidases activity of the bagged fruits of pear cv. Forest Beauty and cv. Dilafruz in the climatic condition of Tashkent region

Authors: Abdurashid Kayumov *, Jakhongir Gafurov Akhroljon oghli, Keisuke Katsura, Yoshiko Kawabata, Takuya Ban, Zukhriddin Ismoilov Sayitkulovich

The firmness and shelf life properties of pear fruits are related to the intensity of peroxidases activity and consequent formation of the monolignol oxidation and polymerization of lignin in the apoplast of fruit tissue. The influence of pre-harvest paper bagging (PHPB) practice on the shelf-life of pear fruits was identified in our previous researches devoted to organic fruit production. After, it was decided to analyze the peroxidases activity of the bagged fruits of pear cv. Forest Beauty and cv. Dilafruz. The pear fruits were covered with white, orange and black double layered paper bags (DLPB) 40-50 days after full blossoming in the orchard situated in Tashkent region. The unripe fruit samples were collected and the activity of peroxidases was assayed using the tetramethylbenzidine (TMB) substrate reaction. The optic densities of reaction batch samples were measured at a wavelength of 450/630 nm. The highest absorbance unit (AU) of peroxidase activity was observed in the fruits of cv. Forest Beauty covered with orange (2.333 AU) DLPB, and cv. Dilafruz, covered with white (2.537 AU), orange (2.541 AU) and black (2.501 AU) DLPB. The lowest AU was observed in the fruits of cv. Forest Beauty covered with white (1.368 AU) and black (1.160 AU) DLPB, and uncovered fruits of cv. Dilafruz (2.331 AU). The results confirm the positive effect of PHPB practice on the activities of peroxidases in fruits of cv. Dilafruz. But, positive effect was observed only in the fruits of cv. Forest Beauty covered with orange DLPB. The reason of various effect of PHPB practice is due to the different biological characteristics of pear varieties.