Effects Of MeJA Etc. On Peel Browning Inhibition Of Postharvest Huangguan Pear And The Mechanism

Huangguan pear is widely planted in China. However, a surface brown disorder with irregular dark brown symptoms often occurs after harvest, which can cause great economic losses. The Physiological and biochemical effects of exogenous methyl jasmonate, abscisic acid and hydrogen peroxide on inhibiting peel browning of ‘Huangguan'pear was studied,the mechanism of postharvest pear browning was preliminary explored by comparing the different gene expression of Huangguan and Xueping pears through the RNA-seq technology. The results showed that:(1) Methyl jasmonate treatment significantly reduced browning rate of post-harvest‘huangguan' pear during low-temperature storage. Compared with control, the activity of PPO and PAL enzymes was significantly inhibited, and the consumption rate of phenolics was retarded. Meanwhile, methyl jasmonate improved the activity of POD, CAT and APX enzymes significantly during earlier storage, reduced hydrogen content, increased DPPH.(2) Abscisic acid treatment can efficiently reduced the peels browning of post-harvest pear. Compared with control, ABA treatment significantly inhibited PPO activity, increased phenolics content. Besides, abscisic acid increased POD and APX activities and alleviated the decrease of antioxidant activities in peel at early stage of low-temperature storage.(3) Hydrogen peroxide treatment clearly reduced the peels browning. Compared with control, PPO activities of pears were decreased significantly. At the same time, POD and APX activities were improved at early stage, leading to the increase of antioxidant activity.(4) During low temperature, ‘Xueqing' pear is less browning. At-1~0 o C, compared with Xueqing, ‘Huangguan' pear's browning rate, electric conductivity and PAL activity were higher, But phenolic content, PAL, PPO, POD activity and DPPH inhibition were reduced. During the research, the difference in gene expression of ‘Huangguan' pear and‘Xueqing' pear using RNA-seq technology, and GO and KEGG pathway at early stage of low-temperature storage were analyzed, which laid the foundation on the coming research.