| Loquat (Eriobotrya japonica Lindl) is a native evergreen fruit tree of China, and can be divided into Hongsha and Baisha red-and white-fleshed categories (also called red-and white-fleshed categories). Loquat fruit color is gorgeous, the flesh is soft and juicy and rich in nutrition. Researches about the quality of loquat fruit are mainly focused on sugar and acid metabolism, carotenoid accumulation, but there are few on the aroma. In this study, loquat fruits were used as materials, the flesh aroma of different cultivars and different developmental stages were analyzed on the basis of the basic quality index and color index determination, and loquat fruit CCD1gene clone and expression were also studied. The main results are as follows:1、The fruit quality of three Hongsha and twelve Baisha cultivars picked at2011were determined. The results showed that "Dawuxing" fruit weight and average diameter were maximum, while those of "Bingtangzhong" were minimum. The TSS of Hongsha cultivars are generally lower than Baisha varieties, with the highest and lowest TSS in "Jidanbai" and "Dawuxing", respectively. In2012, the fruit quality data demonstrated that "Jinfengyihao" and "Guanyu" simultaneously entered rapid development period at4th May2012. Fruit weight and diameter was reached the natural size of these two cultivars1-2weeks before maturity. The average weight of "Jinfengyihao" and "Guanyu" at ripening stage was37.75g and39.96g, respectively. Color difference analysis showed that the peel and flesh brightness of Hongsha cultivars were lower than those of Baisha cultivars, and therefore their color are closer to yellow.The results of the test data show on May4that the same time, fruit weight and size in1-2weeks before it reached maturity variety inherent size,Mature "guan yu" average fruit weight39.96g, greater than2011samples of22.76g, may due to uneven sampling personnel sampling, etc.Chromatic aberration tests showed red pulp varieties the grape skin and pulp brightness than white flesh varieties, and color is more close to the yellow.Fruit aroma component GC-MS detection showed that there were highest average level of alcohols in fifteen loquat cultivars, followed by aldehyde content. The average value of alcohols in Hongsha and Baisha cultivars reached47.7%and53.63%, respectively. Trans-2-isocyano cyclohexanol and benzyl aldehyde were common aroma components in Hongsha and Baisha cultivars among various components. Ther have twenty fore and thiety two kinds of aroma substances were dectected in the fruit of "Jinfengyihao" and "Guanyu" during development process. The highest average content of aldehydes was found in "Jinfengyihao" fruit of seven different developmental stages, followed by acids and alcohols. The average content of aldehydes, acids and alcohols were0.937μg·g-1、0.304μg·g-1and0.163μg·g-1, respectively. The common component of all samples were hexanal, and benzaldehyde and2-hexene aldehyde were among most cultivars. The most common component in "Guanyu" fruit during development process were also aldehydes and then alcohols. Among aldehydes, benzaldehyde and2-hexene aldehyde were found in most samples of different developmental stages, with the value of2-hexene aldehyde content higher than that of benzaldehyde. The highest aldehydes and alcohols contents were both found in "Jinfengyihao" and "Guanyu" in the April19, trans-2-hexene-1-alcohol and hexanol were widespread aroma components.2、Loquat CCD1gene full-length was cloned, and named EjCCD1.The full length cDNA was1735bp long, and contained a1518bp open reading frame, encoding a protein composed of506amino acids. EjCCDl was registered in GenBank with number JQ317781. Moreover, the3’ end fragment of loquat CCD4gene was cloned, and named EjCCD4. The cDNA fragment of EjCCD4was1405bp long, and and contained a1308bp open reading frame, encoding a protein fragment composed of436amino acids. EjCCD4was registered in GenBank with number JQ317782. EjCCDl expression model in the flesh of "Jinfengyihao" and "Guanyu" during different developmental stages were analyzed by Real-time fluorescent quantitative PCR. The results displayed a significant differential expression between different developmental stages, and also in different cultivars of the same period, with the highest expression level at May25,2012. |
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