Effect Of Different Grafting Combinations On Fruit Quality And Related Enzyme Activity Of 'Nanshui Series' Mini Cucumber

Fruit cucumber,also known as mini cucumber,is a vegetable variety with high production and nice flavor quality,which can be eaten as fruit.Protected cultivation usually used for cucumber cultivation.Continuous cropping led to serious soil borne diseases,grafting is one of the most important measures to control soil-borne diseases.Grafting usually caused inevitable negative effect on fruit quality,so this study used two 'Nanshui series' fruit cucumbers and Cucurbita ficifolia and Cucurbita moschata 'Yongzhen 8th' for materials,grafted respectively,to investigate plant growth development,fruit visual appearance,health-related compouds and flavor quality on the grafted combinations,as well as the effect of different grafting combinations on related enzyme activities.To select the rootstock that effect less negatively on fruit qualities and more suitable for mini cucumber grafting.The results are as follows:1.The growth potential of grafting combinations plants increased significantly,the plant height,stem diameter and leaf area increased significantly,plant height of T1 and T3 are lower than T2 and T4,the stem and leaf area are in contrast,the combinations of cucurbita ficifolia as rootstock for grafting is growing stronger than Cucurbita moschata;2.Grafting effected fruit quality and texture.Grafted may increase the fruit length,fruit diameter,fruit firmness and 'single fruit weight,and may influence fruit shape index;'Nanshui 2nd' fruit length changed significantly by cucurbita ficifolia;'Nanshui 2nd' fruit diameter changed significantly by Cucurbita moschata,other grafting combinations have no significant difference compared with self-rooted plants;fruit shaped index of these grafted combinations compared,T1>CK1>T2,T4>CK2>T3;fruit hardness of these grafted combination compared,hardness of T1 and T3 are respectively harder than T2 and T4;the visual appearance of T4 is better,and hard fruit firmness of T3 is better for fruit storage and transportation;3.Grafting effected health-related compouds.There are no significant difference on soluble solids content,soluble sugar and Vc contents of grafted combinations compared to self-rooted plants.The dissociative amino acids of the combinations using 'Nanshui 2nd' as scion are no significance difference compared with self-rooted plants,while 'Nanshui 3rd'are significantly decreased compared with self-rooted plants.In comparison with T2,the soluble solids and soluble protein contents of T1 are significantly decreased,the soluble sugar and dissociative amino acids contents are lower,and titratable acids,Vc and tannin contents are higher;in comparison with T4,the soluble solids,soluble protein,soluble sugar,Vc and dissociative amino acids contents are lower,titratable acids and tannin contents are higher,but nitrate contents are significantly higher than T4;4.Grafting effected fruit flavor quality.(Z,E)2,6-nonadienal,2,6-nonadienol,linalool,-Thans-caryophyllene and Nonane acid contents in grafted fruits reduced compared with CK,in the meanwhile,some unknown-flavor compounds such as 2-pentanenol,2-pentyl-furan,2,4-hexadienal,6-nonenal,(E)-2,4-nondienal,Tetradecanal,(E)-3-nonenlol et al.are lower than CK,there are some compounds increased though,such as Nonanal,2,4-hepdienal,Acetic acid-2-ethylhexyl ester,Tridecanal,2-nonenol,3,6-nonadienol and Heptylate acid.Comparing grafting combinations of two rootstocks,flavor compounds of combinations grafted by Cucurbita moschata were influenced less.The flavor quality of Cucurbita moschata combinations are better;5.Grafting effected fruit quality-related enzyme activities.Fruit LOX and NR activity were significantly reduced by grafting,but no significant effect on SPS and APX activity;SPS,APX and NR activity had no significant difference among different grafting combinations of different rootstocks.LOX activity was significantly influenced,T1 and T3 are respectively lower than T2 and T4;correlation analysis showed that fruit characteristic flavor compounds(Z,E)2,6-nonadienal were negatively correlated with LOX activity in 0.01 level,also,soluble sugar contents were negatively correlated with SPS activity;Vc contents were positively correlated with APX activity,and nitrate contents were positively correlated with NR activity in 0.01 level.So we suppose that the change of fruit quality was related to these enzymes activities changing by grafting.