Genotypic Variation And Environmental Effects On Polyphenols In Leaves, Stalks And Stems Of Sweetpotatoes

China is the largest country of cultivating sweetpotato in the world. The resources of leaves, stalks and stems of sweetpotato are huge. Many researches have reported about sweetpotato, however, little informations which were about sweetpotato leaves, stalks and stems were available. In this paper, the best extraction way for flavonoids, polyphenols of sweetpotato leaves, stalks and stems was constructed by the method of response surface analysis, while with a multiple location experiments of six genotypies and six growing locations of three duplications. The genotype variation and environmental effects on the polyphenols were analysied. The main results were as follows:1. Optimization of ultra sound-assisted extraction of polyphenols from leaves, stalks and stems of sweetpotato using response surface method were studied. The result showed that for the leaves of sweetpotato, the optimal extraction conditions were 60%of ethanol, the ratio of sample to extracting reagent 1:38 and extracting for 40 minutes. For stalks of sweetpotato, the optimal extraction conditions were 60% of ethanol, the ratio of sample to extracting reagent 1:33 and extracting for 26 minutes. And for stems, the optimal extraction conditions were 60% of ethanol, the ratio of sample to extracting reagent 1:33 and extracting for 26 minutes.2. Optimization of ultra sound-assisted extraction of flavonoids from leaves, stalks and stems of sweetpotato using response surface method were studied. The result showed that for the leaves of sweetpotato, the optimal extraction conditions were 81% of ethanol, extracting for 42 minutes and the ratio of sample to extracting reagent 1:42. For stalks of sweetpotato, the optimal extraction conditions were 78% of ethanol, extracting for 35 minutes and the ratio of sample to extracting reagent 1:40. And for stems, the optimal extraction conditions were 78% of ethanol, the ratio of sample to extracting reagent 1:40 and extracting for 35 minutes.3. The polyphenol contents of sweetpotato leaves, stalks and stems samples from the multiple location experiments were determined. Genotypes by location interaction were found to have extremely significant effects on polyphenol content in leaves, stalks and stems of sweetpotatoes. After a comprehensive assessment and analysis, The stability of polyphenols in sweetpotato leaves,stalks and stems from strong to weak are:"Ningyongzi", " Zhe258 "," Zhe738 "," Zhe15"," Xuzi3 "," Xu18 "; " Zhe15 "," Ningyo-ngzi "," Xu18 ", " Zhe738 ", " Xuzi3 ", " Zhe258"; "Zhe738 ", " Zhe15 ", "Zhe258 ", " Ning-yongzi", " Xu18 "," Xuzi3 ".4. The flavonoid contents of sweetpotato leaves, stalks and stems samples from the multiplme location experiments were determined. Genotypes by location interaction were found to have extremely significant effects on flavonoid content in leaves, stalks and stems of sweetpotatoes. After acomprehensive assessment and stable analysis, The stability of polyphenols in sweetpotato leaves,stalks and stems are:" Ningyongzi "> " Zhe258 "> " Xu18 "> " Zhe15 ">" Xuzi3 "> " Zhe738 "; " Xuzi3 "> " Xu18 "> " Ningyongzi ">" Zhe738 ">" Zhe15 "> " Zhe258 "; " Zhe15 ">"Ningyongzi"> "Xu18 "> "Zhe258 ">"Xuzi3 "> " Zhe738 ".The present research results provided a theoretical base for the polyphenols from the leaves,stalks and stems of sweetpotatoes and components analysis.