Analysis Of Metabolite Based On Influence Between Trunk Shape And Y Shape On Fruit Quality Of Peach

Peach(Prunus persica L.Batsch)is a deciduous fruit tree in temperate zones of China.The peach industry is facing a critical period in changing from quantity to quality production.Fruit cultivation techniques have played an important role in the improvement of peach fruit quality.At present,the Y-shape and the main trunk shape are the two main shapes of peach trees practiced and selected before the 1990 s.The Y-shape has the advantage of strong ventilation and light penetration,and the compact shape of the trunk allows for dense planting.One study found that peach tree shape affects fruit quality.In order to investigate the relationship between these two tree shapes and peach fruit quality,this study combined physiological and metabolomic approaches of fruit trees to investigate the differences in fruit quality between trunk shape and Y-shape management patterns.The main research results are as follows:1.Using the RR-9100 canopy photosynthetic gradient observation system to record photosynthetically active radiation(PAR)in the canopy in real time,comparing photosynthetically active radiation at 70 cm and 140 cm from the base of the trunk in the canopy of the two tree shapes.The results show that the PAR of the internal canopy is significantly smaller than that of the external control;the difference between the upper and lower canopies of the Y-shape is greater,while the difference between the upper and lower canopies of the trunk shape is smaller;the upper canopy PAR of the Y-shape is significantly greater than that of the upper canopy of the trunk shape.The two tree shapes and different canopies are ranked in terms of PAR size: Y-shaped upper canopy >trunk-shaped upper canopy > Y-shaped lower canopy > trunk-shaped lower canopy,in general,the Y-shaped tree has higher internal photosynthetic effective radiation.2.Comparison of fruit quality indicators of fruit weight single,yield,fruit hardness,soluble solids,titratable acid and solid to acid ratio,in two consecutive years.The results showed that the Y-shaped single fruit weight was significantly higher than the trunk shape in 2020,and the Y-shaped yield was significantly higher than the trunk shape in two years.The results showed that the hardness of the Y-shaped fruit was generally higher than that of the trunk shape,especially at the top of the fruit,and two years of data showed that the Y-shaped fruit was harder than the trunk shape.Two years of data showed that Y-shaped fruit had higher soluble solids than the trunk shape,which was significantly higher than the trunk shape in 2021.The Y-shaped titratable acid content is lower than the trunk shape in 2020,while the data are reversed in 2021.The two years of data for the solid to acid ratio are reversed,the Y-shaped solid to acid ratio being significantly higher than the trunk shape in 2020,while the data are reversed in2021.The discrepancy between the two years of data may due to differences in rainfall.3.The tree was divided average into upper,middle and lower canopies based on the number of fruit-bearing branches,the data of 2021 showed that the trunk-shaped fruit was more distributed in the lower canopy,while the Y-shape was more evenly distributed in the three canopies.A comparative analysis of the fruit quality indicators of the different canopies in 2021 showed that the Y-shaped upper canopy had a significantly lower fruit weight per fruit than the trunk shape,with no differences in the other canopies.The soluble solids content of all canopies is higher in the Y-shape than in the trunk shape,and the differences in soluble solids content of fruit in the lower canopies are significant.The titratable acid content of all canopies in the Y-shape is significantly higher than that of the corresponding canopy in the main stem shape,while the solid acid ratio of all canopies in the Y-shape is significantl Y lower than that of the main trunk shape.These results indicate that the differences in soluble solids and titratable acid content of fruit in the lower canopy of the two tree shapes are more significant compared to the upper and middle canopies.It suitable for further metabolomic analysis.4.In our study,metabolomic analysis of the fruit in the upper and lower canopies of the two tree shapes was carried out.The results showed that A total of 387 differential metabolites were detected in the lower fruit and 312 differential metabolites in the upper fruit of the two tree forms in the positive/negative ion mode.The differential metabolites of the two tree fruits can be attributed to six main groups of substances:terpenoids,flavonoids,phenylpropanoids,phenols,alkaloids and phenolic acids.Sucrose,fructose and glucose contents are higher in the trunk shape than in the y shape,with significant differences in fructose and glucose.The difference in malic acid content between the two tree shapes was not significant,but the y shape had significantly higher citric acid content in the upper part than the trunk shape.The phenolics associated with astringency,epicatechin,chlorogenic acid,catechin,ferulic acid,quercetin and rutinoside,had lower contents in the Y-shape than in the main stem,with ferulic acid reaching significant differences in both the upper and lower canopies.All three sweet amino acids,including alanine,glutamic acid and aspartic acid,were higher in the Y-shape than in the main stem,with significant differences in glutamic acid and aspartic acid.In summary,the Y-shaped peach tree has significantly better photosynthetic effective radiation inside the tree than the main stem shape.Based on the indicators of soluble solids,weight per fruit,yield and hardness,it can be seen that the fruit quality of the Y-shape is better than that of the main stem shape,while the results of the titratable acid and solid to acid ratio indicators show opposite data for both years.Comparing the fruit quality of the two canopies in 2021,it can be seen that the soluble solids in the lower canopy of the Y shape are significantly higher than those of the main stem shape,while the titratable acid content and fixation ratio are also significantly higher in the Y shape than in the main stem shape.Metabolomic analysis showed that sucrose,fructose and glucose contents were lower in the Y shape than in the main shape,while sweet amino acid contents were all higher in the Y shape than in the main shape.Meanwhile,astringency-related phenolics were lower in the Y shape than in the main shape.