Study On Light Use Efficiency And Related Factors With Calyx Fruit And Rough Fruit Of Korla Fragrant Pear Tree

Korla fragrant pear (Pyrus brestschneideri Rehd.) is belonging to Rosaceae, Pomaceae, Pyrus, is one famous special product among three special product of Xinjiang. With developing of fruit industry in Xinjiang, cultivating area and yield of Korla fragrant pear has been enlarged obviously. Meanwhile, the deterioration of fruit quality such as calyx fruit and rough pear has been increased gradually, and the increasing of fruit yield has basically depended on frequently using of chemical fertilizer and pesticides, the lowest proportion of improvement on orchard management level among stimulation measures has been influenced competition power of Korla fragrant pear in international fruit market. In this paper, Korla fragrant pear is used as experimental material, and the scientific best tree shape and leaf fruit ratio were filter out by comparing of the light use efficiency between open-center tree shape and evacuation layered tree shape, and proposed corresponding internal and external cause by analysing of the correlation between tree canopy light distribution with calyx or non-calyx pear and rough pear. Main results as follows:1. Some significant difference was observed in photosynthetic characteristics between full-sunlight and shade leaves of Korla fragrant pear. With compared full-sunlight leaf, the shade leaves has been charactered by higher chlorophyll SPAD value (43.68,45.13), lower light saturation (1404μmol.m-2.s-1,260μmol.m-2.s-1), higher apparent quantum yield efficiency (0.0405、0.124), lower stomatal conductivity, lower transpiration rate, lower photosynthesis rate and higher intercellular CO2concentration, Higher actual efficiency of PS Ⅱ photochemistry (ΦPS Ⅱ), maximum quantum yield of PS Ⅱ (Fv/Fm) and electron transport rate (ETR) and lower non photochemical quenching coefficient.2. The fruit longitudinal and transect diameter, average weight under full sunlight were significantly higher than fruit under shade, but there was no remarkable effect of light condition on fruit shape index. The fruit soluble sugar content and soluble solids content under full sunlight observed remarkable high value compared to fruits grown shade condition, but it’s titratable acid content was lower than shade fruit. The fruits grown full sunlight expressed rosiness color, fruits grown shade expressed green color, the lustrousness and yellow color degree of fruit grown full sunlight condition were lower than fruits grown under shade condition. There were no any significant effect of light condition on fruit firmness, water content and Vc content, but fruit stone cell content grown full sunlight condition was higher than fruit grown shade condition.3. There ware no significantly difference between two tree shape on chlorophyll content, the content value was ranged within17mg·cm-2～41mg·cm-2. The diurnal change in net photosynthetic rate of Korla fragrant pear was presented a double-peak curve mainly because of light inhibition by stomatal factor; the photon flux density over than light saturation point of Korla fragrant pear is the main factor caused light midday depression phenomenon. The diurnal change in photosynthetically active area in two tree shape wwre basically similar, among them the photosynthetically active area in evacuation layered tree shape was always higher than open center tree shape, average value were23.8m2、21.6m2, respectively. In leaf fruit ratio analysis, the correlation coefficient between leaf photoactive chlorophyll content and fruit wight is highest among the other index correlation coefficients.4. tree shape have not remarkable affect on flower number in an inflorescence, but there was significantly difference on flowers number in an inflorescence among different years old tree, the frequent flower number in an inflorescence of12,23,47years old Korla fragrant tree are4,7,6, respectively. The flowers number and flower distribution density of evacuation layered tree shape was higher than open center tree shape, the difference was most obvious between23year old trees, and the difference on47year old tree was not remarkable. The set fruit rate and fruit distribution density of different year old Korla fragrant tree in evacuation layered tree shape were significant higher than open center tree shape, especially the fruit distribution density of evacuation layered tree shape in12,23year old were higher in several or more times compared to open center tree shape, but there were a little difference between two kind tree shape in47years old.5. Artificial pollination could enhance fruit setting rate, but there was no any direct relationship between artificial pollution and abscission or persistanting of calyx. The C/N in leaves grown in shade condition was significantly higher than the leaves grown in full sunlight. In abscission layer forming stage, there were some remarkable difference on plant regulars content between calyx and calyx end part of fruit. Contrary to calyx fruit, calyx on non-calyx fruit had higher abscisic acid (ABA), lower Auxin (IAA) and gibberellic acid (GA3) compared with calyx end part of fruit. Expunging of calyx with ring zone have best effect on transforming of calyx fruit into non-calyx fruit.6. The survey on rough pear relational factor indicated that percentage of all rough pears in an inflorescence was100%; there were no any remarkable correlation roughpear with density of sunlight. There were no any significant difference on K+, Mg2+, Fe2+, Zn2+content in rough pear and it’s adjacent leaf compared to normal pear and it’s adjacent leaf, but the Na+, Ca2+content in rough pear and it’s adjacent leaf were remarkable lower than normal pear and it’s adjacent leaf.