Effects Of Flowering Temperature Changes Of Abscisic Calyx And Persistent Calyx Fruit Of Korla Fragrant Pear Formation

Two orchards(I and II) of different average temperature at night are selected, and the Korla fragrant pear is taken as the experimental material. During the per iod of full bloom, low temperature treatment(5 ?) was applied in orchard II at night. The time gradient was set as 5? for three nights(D3), 5? for two nights(D2) and 5?one night(D1) respectively. The CK was also set in orchard I(CK1) and orchard II(CK2). The content of IAA, GA3, ZT, ABA, and nitrogen, phosphorus, potassium, calcium, magnes ite, and Endo-1,4-?-D-glucanohydrolase(EGase), Polygalacturonase(PG) activity were measured and tested in the fruitlet stage of sepals abscission layer formation. Fruit quality index of abscisic and persistent calyx Kor la fragrant pear such as sugars content, Vitamin C, titratable acid, tannins, stone cells and fruit shape index were analyzed at last. The main results were as follows:1. The EGase, and PG activity were increased when the bloom temperature of Korla fragrant pear in orchard II is decreased compared with orchard I at night, which results in abscisic fruit rate was higher than that in orchard II. In addition, two kinds of enzyme activity in sepals and abscisic fruit rate were further increased when the low temperature treatment(5?) at night was applied in orchard II during blooming.2. The effect of fruitlet endogenous hormone content on persistent calyx showed that the ratio of ABA/GA3 and PG, EGase activity were positive correlated with the fruitlet stage of sepals abscission layer formation, PG and EGase activity in sepals. In other words, the abscisic fruit rate was increased when the ratio of ABA/GA3 was increased in young fruit. Besides from D1 to D3, the ZT content of persistent calyx fruit was increased. While the contents of ABA and GA3 were kept the same trend of changing in abscisic and persistent calyx Korla fragrant pear during the formation of the abscisic and persistent calyx fruit.3. The effect of fruitlet mineral nutrient content in abscisic on persistent calyx of Korla fragrant pear showed that the Potassium content and EGase activity in sepals were negative correlated in the fruitlet stage of sepals abscission layer formation. The calcium content and EGase, PG activity were positive correlated. It indicates that the Calcium, Potassium content have a great relationship with EGase, PG activity in sepals. Therefore, PG and EGase activity in sepals and abscisic calyx were increased when the Calc ium and Potassium content were reduced after low temperature treatment. In addition, From D1 to D3, the Potassium content of abscisic calyx fruit was reduced, and Magnesium, phosphorus content was uptrend. Calcium content in persistent calyx fruit was reduced.4. The effect of fruit quality showed that fruit weight of the abscisic calyx fruit of D3 was signif icantly reduced compared with CK2. And the edible part of fruit was reduced due to stone of the fruit was relatively larger. From D1 to D3, Vc content of persistent calyx fruit was gradually declined compared with CK2. The sugar content of abscisic and persistent calyx fruit were increased compared with CK2, and the titratable acid content were reduced continuously. What's more, the solid-acid ratio, sugar-acid ratio were increased, which was useful to improve the fruit quality of fragrant pear.