Amino acid accumulation characteristics in pericarp of germinating branches of Zanthoxylum planispinum var. dintanensis in different seasons

【Objective】To discuss how branch germination season influence amino acid content and composition in pericarp of Zanthoxylum planispinum var. dintanensis, so as to provide a theoretical basis for improving fruit quality of Z. planispinum var. dintanensis through tree management.【Method】The types and content of amino acids in the pericarp of Z. planispinum var. dintanensis germinating backbone branches in different seasons were determined and analyzed and its nutritional value was evaluated according to FAO/WHO amino acid reference model. The nutritional status was comprehensively evaluated by principal component analysis.【Result】At least 17 types of amino acids were contained in the pericarp, among which glutamic acid(Glu), aspartic acid(Asp) and leucine(Leu) were plentiful. Amino acid content varied with the season of branch germination, which were 7.45, 6.98 and 5.52 mg/g in spring, summer and autumn shoots respectively. Amino acid content in the spring shoots were the most pentiful, that in the summer shoots were the second, and that in the autumn shoots were the lowest. The contents of isoleucine(Ile) and lysine(Lys) were significantly different among autumn shoots, spring shoots and summer shoots(P<0.05). The contents of Ile and Lys in autumn shoots were 89.21% and 27.71% lower than those in spring shoots, and 89.27% and 18.76% lower than those in summer shoots. The accumulation of gustatory amino acids, medicinal amino acids and branched chain amino acids in the 3 treatments were as follows:Spring shoots>summer shoots>autumn shoots. The essential amino acid(EAA) of spring shoots and summer shoots were the most close to the FAO/WHO model spectrum. The amino acid ratio coefficient of spring shoots(SRC) was the highest, 66.08;and that of summer shoots was the second;and the lowest was that in autumn shoots, indicating that the spring shoot and summer shoots fruit had more balanced greater nutrition. The correlation among amino acids in the pericarp of Z. planispinum var. dintanensis in different germination seasons was strong, indicating that the amino acids were closely related with a significant coupling relationship.【Conclusion】According to the results of nutritional value, medicinal value and principal component analysis, and taking into account the convenience of management, the germinating branches in summer are suitable to be cultivated as backbone shoots to improve the amino acid quality of Z. planispinum var. dintanensis fruit.