| In this study,Fujian's unique citrus variety‘Fuju'was used as the experimental material.The extraction process of carotenoids in the mature peel was optimized by response surface methodology.By investigating the light conditions of the canopy,the effects of different canopy lights on the fruit color changes and fruit quality during the growth and development of Fuju were explored;the relationship between sink and source was adjusted through the leaf-fruit ratio and the girdle experimental to study the fruit growth and development process Changes in peel color and fruit quality;Finally,the UPLC method was used to qualitatively and quantitatively analyze the sugar and carotenoid accumulated in the peel of Futang under the control of different cultivation techniques,and to explore the relationship between the sugar components and carotenoid components and their contents in the peel.The main research results are as follows:1.In this experiment,In this experiment,ultrasound-assisted extraction was used to extract carotenoids from Fuju peel.On the basis of single factor experiment,the extraction process was optimized by response surface analysis with liquid-solid ratio,extraction temperature,and ultrasonic power as influencing factors and extraction amount of carotenoids as response value.The results showed that the best carotenoid extraction effect was achieved under the conditions of liquid-to-material ratio,ultrasonic power and temperature was 59:1?m L/g?240 W and 50?,and the number of extractions was twice,the extraction time was 10minutes.Under these conditions,the total carotenoids extracted from Fuju peel was?0.747±0.027?mg/g,which was basically consistent with the predicted value.2.The PAR in the canopy is inner upper>inner middle>outer middle>outer lower>middle lower>middle middle,the fruit quality of the the former four is better than the others;the results of significant analysis indicate that the in mature the intrinsic quality of the fruit in each part of the period is quite different,but most differences between external qualities are not significant.It can be seen that PAR has more influence on the internal quality of the fruit than the external quality;regression analysis was carried out based on the monthly average PAR value of each part as the independent variable and fruit quality as the dependent variable.The results show that the best monthly average PAR value in the canopy should be controlled between 576.47 to 989.67 mol·s-1·m-2.In actual production,in order to adjust the spatial distribution and number of branches and leaves to improve the PAR in the canopy,we can adopt measures such as:removing the large auxiliary branches of the inner or the large branches around the light and the skirt branches that are too large near the ground,pulling the branches to increase the angle of the branches,and laying the reflective film and so on.3.The leaf-fruit ratio treatment experimental showed that leaf-fruit ratio had a greater impact on the color of Fuju peel and the intrinsic quality of the fruit.When the leaf-fruit ratio is 30:1,the color of Fuju peel is orange-red,the total carotenoid content of the peel is the highest,the total chlorophyll content is the lowest,the sugar-acid ratio is significantly higher than other conditions;When the leaf-fruit ratio is 70:1,The peel color is yellowish,the sugar-acid ratio is low,and the overall performance is the worst.In the actual production process,the leaf-fruit ratio of the third-level branch can be controlled at about 30:1,which is beneficial to fruit coloring and fruit quality improvement.4.From 180 days to 200 days after flowering,girdle was performed to improve the quality of the fruit.In 2019,girdle is performed every 10days from 180 days to 200 days after flowering,and the quality of fruits during growth and development is measured,and the fruit quality of girdle treatment is comprehensively evaluated by principal component analysis.The results showed that the ring cut treatment improved the quality of Fuju fruit.The first three treatments with the highest scores was perform 2 ring cuts at 200 d after flowering,2 ring cuts at 190 d after flowering and 1 ring cuts at 200 d after flowering.5.The ripe Fuju peel contains a lot of violaxanthin,?-citrullin,zeaxanthin,and?-cryptoxanthin,and the sugar content is mainly sucrose.From the perspective of growth and development,the contents of sucrose,fructose and glucose in the peel show a continuous upward trend;lutein,?-carotene and?-carotene in the peel show a downward trend while violaxanthin,zeaxanthin and?-citrullin showed an upward trend,and?-citrusin was detected during the color change period.Taking 200 days after flowering as the t-off point,the early peel mainly contains lutein and?-carotene.As the fruit matures,a large amount of zeaxanthin,violaxanthin,?-citrullin and?-cryptogen are finally enriched in the peel.6.Correlation analysis was carried out on the relevant indicators of the color and the soluble sugars of Fuju peel under different treatments during the growth and development.The experimental results showed that the soluble sugar content was significantly related to the carotenoid content.The sugar content and carotenoid content in the peel under the30:1 leaf-fruit ratio treatment were the highest.The three components of fructose,glucose and sucrose were also higher than those in other treatments.The violaxanthin and zeaxanthin in the peel at the mature stage,?-citrullin and?-cryptoxanthin accounted for a larger proportion,and 30:1?-citrullin and?-cryptoxanthin were significantly different from other treatments;The results of the determination of the pigment component showed that the content of soluble sugar and sugar component in the part with sufficient light was higher than that in the part with insufficient light,and there was a significant difference between?-citrusin,?-cryptoxanthin and zeaxanthin in each part during the mature period Difference;ring cut treatment also has a certain effect on the content of peel sugar and carotenoid.In summary,the average monthly PAR value in the canopy of Fuju should be controlled between 576.47-989.67 mol·s-1·m-2;It is better to control the leaf-fruit ratio of the third-level branch?the base branch of the fruiting mother branch?to about 30:1;200 d post-flowering and 2 cuts in190 d after flowering can improve the color and fruit quality of Fuju peel..The carotenoids in the orange peel at the mature stage are mainly violaxanthin,zeaxanthin,?-citrullin and?-cryptoxanthin. |
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