Effects Of Shading Fruit With Opaque Paper Bag On The Quality Including Carotenoid Accumulation And Related Gene Expression In Yellow-flesh Peach

Effects of shading fruit with opaque paper bag on the quality, accumulations of chlorophylls and carotenoiods, as well as on the carotenogenesis related gene expression, were studied in two yellow-flesh peach(Prunus persica L. Batsch) cultivars: ‘Babygold 6’ and ‘Babygold 8’. The main results are as fellows:1、During the fruit development and ripening the contents of chlorophyll were declined gradually both in peel and flesh, and they were significantly lower in the bagged fruits compared with the non-bagged fruits in each sampling period2、The contents of carotenoid were increased during the fruit development and ripening. It was noted that, compared with the non-bagged flesh tissues, the bagged flesh tissues accumulated less carotenoids at the immature stage, but they accumulated a significantly higher level of carotenoid at the mature stage.3、HPLC analysis indicated that carotenoids in the immature flesh tissues were mainly composed of lutein and β-carotene, which represented a chloroplast-specific carotenoid biosynthesis pathway; chromoplast-specific carotenoid biosynthesis pathway was preponderant in the mature flesh tissue, characterized by abundant accumulation of stable estered cryptoxanthin and violaxanthin. In addition, it was noted that there were more carotenoid eaters in the bagged fruits than in the non-bagged fruits.4 、 Transcriptional analysis revealed that genes encoding enzymes for HDR(hydroxymethylbutenyl 4-diphosphate reductase), PSY1(phytoene synthase 1), PSY2(phytoene synthase 2), phytoene desaturase(PDS), and HYD(β-carotene hydroxylase) showed higher expressive levels in the mature flesh than in the immature flesh. However, HYD gene was the only one which showed the significantly different expression in the bagged fruit as compared to the non-bagged control.5、The contents of tatal soluble sugar, fructose,sucrose and Vc were gradually increased during the fruit development and ripening. On the contrary, the malic acid and starch were decreased during the fruit development and ripening. The treatment of bagging made the contents of malic acid, starch and Vc decreased,while it have no effect on the tatal soluble sugar, fructose and sucrose.