| Skin color is an important out feature of pear fruits, and also the very important indicator of commodity value. The germplasm resources of pears are divided into three ca according to skin color, that are green pear(including green, yellow, yellow-green), beige pear(including green-brown, yellow-brown, red-brown, brown) and red pear(including part colored and full colored). The majority of cultivated pear in china varieties range from yellow green to brown with few red skin colors. This cultivars is not easy to attract consumers but red pear. Therefore, cultivate high-quality red pear varieties and pear germplasm in breeding had been to a hot spot in china. In this study, the system of anthocyanin’s extraction and detection by high-performance liquid chromatography in red pear were established, the composition and content of anthocyanin in red pear were compared between different cultivars, years and cultivated area and the effect of different cultivation practices on coloring in red pear. The results indicated as follows:1. The system of anthocyanin’s extraction and detection by high-performance liquid chromatography in red pear were established by comparing different extracting solution and the conditions of high-performance liquid chromatography.1% Hcl-methanol is the most effective buffer for anthocyanin extraction. The mobile phase was prepared from acetronitrile/formic acid/water (45:10:45, v/v/v), solvent A and 10% formic acid, solvent B. The gradient profile was 5% A at 0 min; 10% A at 10 min; 20% A at 20 min; 30% A at 25 min; 35% A at 40 min. The total running time was 45 min with a flow rate of 0.8 mL/min. The linear equation is greater than 0.9991, the average recovery larger than 94.58%(n=5), RSD≤3.06%, the lowest detection is low than 0.66μg·mL-1(S/N=3). The method is contented for the requirement of experiment.2. The characteristics of components and contents of anthocyanin in 37 cultivars of pear fruit were determined to reveal the differences and characteristics among different cutlivars and species. The High Performance Liquid Chromatography (HPLC) was used to detect the components and content of anthocyanin in mature pear fruit, and data were analyzed by principal component analysis (PCs) and cluster analysis. The results showed that, the major components of anthocyanin in mature pear fruits were cyaniding-3-galactoside, cyaniding-3-glucoside, cyaniding-3-arabinoside, peonidin-3-galactoside and peonidin-3-glucoside, and the cyaniding-3-galactoside content showed the highest value, which account for 66.49% of the value of total anthocyanin, cyaniding-3-glucoside and peonidin-3-galactoside were taken 11.43% and 9.71% separately, and both the cyaniding-3-arabinoside and peonidin-3-glucoside were taken a little percentage. Among the different cultivars the anthocyanin’s content appeared quite differently and also the anthocyanin’s component showed some differences. cyaniding-3-galactoside and peonidin-3-galactoside are the major part in P. communis Linn, P. bretschnrideri Rehd, P. ussuriensis Msxim, P. sinkiangensis Yu, which account for 68.80% and 13.70% of the value of total anthocyanin; cyaniding-3-galactoside and cyaniding-3-glucoside are the major part in P. pyrifolia Burm Nakai, which were taken 60.08% and 23.07% separately.3. The experiments were conducted on’Yunhongli 2’with the bagging and exogenous 5-aminolevulinic acid (ALA) treatment. The content of pigments in peel, activity of key enzymes paticipating in anthocyanin synthesis, content of total soluble sugar and endogenous ALA were analized, and the relationships among content of peel pigments, activity of enzymes and total soluble sugar were also investigated. The results showed that bagging and exogenous ALA treatment both promoted coloration remarkably at the early stage of fruit coloration, and the effects of using them together was better, the content of pigments in peel showed dereasing along with the fruit maturation. According to the experiment results, it suggested around 5 days before ripeness, under normal sunshine, as the appropriate time to remove bags for coloration improving. Correlation analysis indicated as follows, the pigments content in peel was significantly relevant to the activity of PAL with bagging treatment; and was remarkably relevant to the activity of UFGT in all treatment, but showed no significant relationship with the content of total soluble sugar of fruit.4. Experment was conducted with’Yunhongli 2’cultivar to investigate the effects of different color bags on chlorophyll, flavonoids, total phenolics, anthocyanin content and the activity of enzymes paticipating in anthocyanin synthesis. The results showed that chlorophyll, flavonoids, total phenolics affected the ground colour, and the content of anthocyanin decided the appearance of red sad pear. The content of anthocyanin was determined by the ration of red and far-red light and the transmissivity of short wavelength light, such as violet. While Red/far-red>1 and the higher transmissivity of violet, the better coloring. The content of anthocyanin mainly depended on the effect of light quality on the activity of DFR and UFGT. The activity of PAL was regulated by light quality, but PAL was not the key enzyme of anthocyanin synthesis.5. The sad pear cultivar ’bayuehong’ and ’hongxiangsu’ were adopted as material, we observed the change of the apparent color during fruit development phase, and the changes of the compose and content of anthocyanin was detected. The results showed that the change regularity of the compose and content of anthocyanin among different cultivars was different, but the regularity of particular cultivar was stable which was not effected by culture area and observation time. The absolute content of anthocyanin was affectd by different culture area. The high latitude maked for the anthocyanin synthesis. |
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