【作者】 刘玉莲；

【导师】 赵政阳；

【作者基本信息】 西北农林科技大学 ， 果树学， 2013， 博士

【摘要】 苹果果实的着色状况以及糖酸含量很大程度上决定果实的品质及其商品价值，因此有关果实品质方面的研究一直为研究人员所关注，尤其是色泽调控机理方面的研究已成为最热门的植物次生代谢研究之一。本研究在西北农林科技大学白水苹果试验站进行，以深红色品种（新红星）、红色品种（粉红女士）、黄色品种（金冠）和绿色品种（澳洲青苹）为试材，利用套袋技术进行遮光处理，研究解袋后不同色泽类型苹果着色过程中果实中可溶性糖和有机酸的种类、含量特征和变化规律，以及解袋后4个品种的表面颜色变化、花青苷种类及其相关合成酶（苯丙氨酸解氨酶（PAL）、查耳酮异构酶（CHI）、二氢黄酮醇还原酶（DFR）、类黄酮-3-O-糖基转移酶（UFGT））的活性变化，为品质育种的亲本选择和花青苷的调控机制提供理论依据。获得的主要研究结果如下:（1）采用超声波纯水提取法，检测条件为Sugar PakTMI色谱柱；柱温为80℃；流动相为超纯水；流速0.6mL/min；2414示差折光检测器。在上述条件下，检测出苹果果肉中含有果糖、蔗糖、葡萄糖、山梨醇和UDP-半乳糖等5种可溶性糖，且分离度良好；5种可溶性糖的线性范围在0.01～50mg/mL之间，回收率在91.00～101.62%范围内、精密度良好(RSD:1.27～2.34)。（2）研究发现不同色泽类型苹果解袋后果皮色泽参数a*值升高， L*、b*、h0降低，C*先下降后升高，表现为果皮表色（红色）迅速发育，覆盖底色（黄色和绿色），导致果实表面亮度降低，色泽饱和度增加。（3）不同品种苹果果实中花青苷种类和含量存在差异。红色品种‘新红星’和‘粉红女士’果皮中检测出矢车菊素3-半乳糖苷（cy3-gal）、矢车菊素3-阿拉伯糖（cy3-ara）和矢车菊素3-葡萄糖苷（cy3-glu），而绿色品种‘澳洲青苹’和黄色品种‘金冠’着色后果皮中只检测出cy3-gal、cy3-ara。果皮中不同种类的花青苷含量差异显著，其中cy3-gal含量最高，但含量较少的花青苷种类可能因品种差异而有所不同。果皮中花青苷含量在解袋以后变化显著，尤其是在解袋后的前6d，花青苷积累最为迅速，之后花青苷的含量虽然也在增加，但速度相对减慢。苹果果皮中所含有的主要花青苷cy3-gal与亮度色泽参数L*和黄色度参数b*呈极显著的负相关，而与红色度值呈极显著的正相关；因此苹果果皮中cy3-gal含量对果皮表面颜色的形成起着决定性的作用。（4）不同色泽类型苹果果实中含有的有机酸种类相同，均含有苹果酸、草酸、琥珀酸、柠檬酸和乙酸，但不同种类有机酸的含量存在明显差别。苹果酸为成熟期苹果果实中含量最高的有机酸，是决定品种酸度的主要因素；琥珀酸和乙酸在红色品种中含量较高；而柠檬酸却在非红色品种中的含量较高；‘金冠’的草酸含量明显高于其它三个品种。解袋后0~2d，各种有机酸都存在一个迅速合成的阶段，说明套袋显著抑制了果实中有机酸的合成。（5）不同色泽类型苹果果实所含有的可溶性糖种类一致，均含有果糖、葡萄糖、蔗糖、山梨醇和UDP-半乳糖等5种可溶性糖。通过对着色期花青苷和可溶性糖的相关性分析发现，花青苷积累与蔗糖和果糖含量变化呈显著正相关，与其它可溶性糖含量变化相关性不明显，其中也包括花青苷合成的直接前体物质—UDP-半乳糖。（6）避光处理强烈抑制PAL、CHI、DFR和UFGT4种酶的活性，完全抑制了果皮中花青苷的合成;解袋后的着色过程中4种酶活性均会出现快速增加的过程，进一步证明了PAL、CHI、DFR和UFGT酶的光调节特性以及对花青苷的生物合成协同作用。前述4种酶在不同品种中的活性有所差异。表现为：红色品种‘新红星’和‘粉红女士’的PAL、CHI和DFR活性均高于非红色品种；晚熟品种‘粉红女士’和‘澳洲青苹’的UFGT活性高于中熟品种‘新红星’和‘金冠’；对解袋后不同色泽类型苹果的花青苷合成相关酶活性与花青苷积累的相关性进行分析发现，仅有UFGT与非红品种果皮中花青苷积累具有显著相关性。由此推测在非红色苹果着色过程中UFGT可能起着更为重要的作用。更多还原

【Abstract】 Fruits quality and commercial value depends on their color quality and content of sugarand acids, so many scientists pay attention to study of this field, especially the regulationmechanism of coloration, already being as one point of the most popular plant secondarymetabolism research. This research project was conducted at the Apple Experimental Farm ofNorthwest A&F University. Taking dark red cultivar ‘Starkrimon’, red cultivar ‘Pink Lady’,green cultivar ‘Granny Smith’ and yellow cultivar ‘Golden Delicious’ as sample. The aim ofthis study is to provide theory basis for parent selection of fruit quality breeding andcontrol-mechanism of biosynthesis anthocyanins. This first stage is using paper bags to avoidlight for apple fruits, the second stage is removing the paper bags, then find the changing lawof types and content of soluble sugar, organic acids, also study the fruits appearance colordegree, types of anthocyanin, activity of the related anthocyanin enzymes (phenylalanineammonia-lyase, PAL; chalcone isomerase, CHI; dihydroflavonol4-reductase, DFR andUDP-Glucose: flavonoid-3-O-galactosyl transferase, UFGT). The main result as follow:(1) Soluble sugars were extracted from apple fruits by ultrasonic-assisted waterextraction. A Sugar PakTMI6.5mm×300mm (Waters) column was used to separate solublesugars. The mobile phase was redistilled water with a flow rate of0.5mL/min. The columntemperature were set as80℃. Under chosen experimental conditions, five soluble sugarscould be successfully separated. All the calibration curves for these soluble sugars displayed agood linear relationship with correlation coefficients above0.9998and repeatability RSDs of0.27%-2.34%(n=5). The recovery rates of five soluble sugars were in the range of90.1%-106.20%. Conclusion: The method is convenient, rapid, accurate and applicable to determinesoluble sugars in apple fruits.(2) After bag removal, the L*, b*and h0values decreased, a*values increased and C*values dropped at first and rose later. The main manifestations on color of apple peel included:surface color (red color) development rapidly, which tends to mask the ground color (yellowand green color); brightness of fruit surface decreased and color saturation increased。(3) There were different anthocyanins in different apple cultivars. Three anthocyanins, cyanidin3-galactoside, cyaniding3-glucoside chloride and cyaniding3-arabinoside wereidentified in ‘Pink lady’ and ‘Starkrimon’, and two anthocyanins, cyanidin3-galactoside andcyaniding3-arabinoside, were found in ‘Granny Smith’ and ‘Golden Delicious’; there weresignificant differences in contents of different anthocyanins, cyanidin3-galactoside was themost abundant anthocyanin. The anthocyanin content progressively changed after bagremoval especially in the first six days, the results also showed that the first six days after bagremoval is a very important stage for the bagged apple coloring. Significant negativecorrelation were observed between the cy3-gal accumulation of4cultivars and L*, b*. Andsignificant positive correlation were observed between cy3-gal and a*. So cy3-gal was themore important factor in the surface color of apple.(4) There weren’t differences in organic sugars of4apple cultivars. Malic acid, oxalicacid, citric acid, and succinic acid were identified, however the contents of various organicacids were different, the highest amount of organic acids was malic acid. Concentrations oforganic acids quickly increased during0~2DABR, suggesting that synthesis of these showsthat fruit bagging inhibited the organic acid synthesis.(5) It was found that the soluble sugars were similar in ‘Starkrimon’‘Pink Lady’,‘GrannySmith’ and ‘Golden Delicious’, the only difference was its relative contents. Five solublesugars were identified in all cultivars, and the highest was fructose, followed by glucose andsucrose, galactose and sorbitol contents were the lowest. Analysis shows, that during applecoloring, significant positive correlation was observed between the changes of anthocyanins,especially cy3-gal contents and sucrose contents during coloration in apple, which indicatedthat sucrose might be responsible for the regulation of cy3-gal biosynthesis in apple skin.(6) The debagging4cultivars showed lower PAL、CHI、DFR and UFGT activities thanthose of exposed peel, and the activities of4cultivars rapidly increased at first, and thenslowly increased until15DABR, this show that the activities of PAL、CHI、DFR and UFGTwere induced by light. There were differences in PAL, CHI, DFR and UFGT activities of4apple cultivars. PAL, CHI and DFR activities were higher in red cultivars than those ofnon-red cultivars apple peel, and UFGT activities were higher in late-maturing varieties thanthose of medium varieties. The cy3-gal accumulation of non-red cultivars tested was notsignificantly correlated with PAL, CHI and DFR activity, but was significantly correlatedwith UFGT activity. During the reddening of non-red apples, UFGT may be the moreimportant factor in the anthocyanin biosynthesis.更多还原