Effects Of High Voltage Electrostatic Field On The Fruit Quality And Expression Of Leucoanthocyanidin Reduetase In Grape Berries

Polyphenols not only provides the plant resistance to the stress, such as ultraviolet rays, pest, ion toxicity and other functions, but also play an important role in the color and flavor of grape fruit. Meanwhile, polyphenols has a decisive effect on the organoleptic qualities of wine, such as color, flavor, clarity, brownchange, etc.In this study, the grape (Vitis vinifera L. cv. Cabernet Sauvignon) berry were treated with high voltage electrostatic field (HVEF), and the effects of HVEF treatement on the quality of grape berries.and the accumulation of flavnols, the expression of leucaonthocyanidin reductase (LAR) enzyme were studied. The main results were as follows:1. HVEF obviously affect the quality of post-harvested grape berry. HVEF treatment significantly inhibited the decreased of total soluble sugar and organic acid The total soluble sugar and organic acid content in treated fruit was significantly higher (P<0.05) than CK at60minutes. HVEF inhibited the decreased in the vitamin C, but the difference was not significant.2. HVEF obviously effect on the accumulation of polyphenols in grape berries. In the most time, compared to CK, ther was no significant differents in total phenols and flavanols, but the total flavonoids, total flavan-3-ols and anthocyanin content was higher (P<0.05), especially at30minutes,60minutes, and120minutes.3. HVEF treatment significantly inhibited the accumulation of MDA in grape berries, induced the increased in activity of protective enzyme, such as SOD, POD, and CAT, thereby reduced the reactive oxygen damage to cells, maintained the cell activity.4. The activity of LAR enzyme in the post-harvest grape berry was significantly increased at60minutes and120minutes (P<0.05) by HVEF.5. Western-blot analysis indicated that a43KD polypeptide was detected in post-harvest grape berry. The protein expression leves of LAR1incteased significantly at30minutes and60minutes, and at30minutes and120minutes,the protein expression leves of LAR2incteased significantly.6. The result of Real time PCR showed that HVEF induced the expression levels of Vvlar1and Vvlar2in post-harvest grape berries. The expression levels of Vvlar1significantly increased at30minutes,60minutes,120minutes (P<0.05), and at60minutes, the expression levels of Vvlar2increased significantly (P<0.05).