Abstract: To comprehensively give insight on the diversity and nutritional level of amino acids in Eucommia ulmoides male flowers,the content and composition of amino acids were determined in male flowers of 193 germplasm materials.17 amino acids were examined in E.ulmoides male flowers,in which the average content of total amino acids was 20.62 g/100 g and aspartic acid and glutamic acid were the 2 primary amino acids.In different E.ulmoides germplasms,the variation coefficient value of methionine amino acid content was the highest (43.13%) and the total amino acids the lowest (12.56%).The protein closeness degree of E.ulmoides male flower was 0.887.Among all the essential amino acids of E.ulmoides male flower,the ratio of (Met+Cys) was lower than ratio the FAO/WHO recommended,the RAA and RC value were numerically close to 1 and the average value of SRC was 81.42.The contents of children essential amino acids,taste-active and therapeutic amino acids were evidently higher than the other 6 plant pollens including G.biloba. Significant difference of E.ulmoides amino acids content was found in different origins,the content of total amino acids and essential amino acids of the Guizhou germplasm were 21.32 g/100 g and 7.50 g/100 g,respectively and were found to be the highest.However,non-significant difference of amino acids nutritional value was found.Cluster analysis results indicated that 193 E.ulmoides germplasms were divided into 4 groups,the average contents of the total amino acids,the essential amino acids,the sweet amino acid and aromatic amino acids in the second group were higher than the other 3 groups,and respectively reached to 22.46,7.92,4.10 g/100 g and 1.64 g/100 g.The amino acids in E.ulmoides male flowers were considered to be of important nutritional value,and high genetic diversity was found in different germplasms.The results of this study provided basic waterials for the further research and development of E.ulmoides male flowers.

Key words: Eucommia ulmoides, male flowers, amino acids, diversity, nutritional value