Varieties. Stem Mustard Glucosinolates Components And Contents And Differences Between Organs

Tuber mustard(Brassica juncea var. tumida Tsen et Lee) is an original Chinese vegetable that can be processed into a very delicious food with special flavor called Zhacai. Glucosinolates are important natural plant products found mainly in Brassicaceae family. The hydrolysis products have many different biological activities, such as characteristic bitter flavor and defense compounds. In order to analyze the glucosinolate (GS) composition and content in various organs and varieties of tuber mustard, tissues of roots, swollen stems, leaves and floral buds of thirteen varieties were sampled at floral bud emergence stage. A total of nine glucosinolates were detected in different varieties and various organs, including four aliphatic glucosinolates (2-Propenyl GS,3-Butenyl GS,1-Methylpropyl GS and 1-Methybutyl GS), four indolyle glucosinolates (4-Hydroxyindol-3-ylmethyl GS, Indol-3-ylmethyl GS,4-Methoxyindol-3-ylmethyl GS and 1-Methoxyindol-3-ylmethyl GS), and one aromatic glucosinolate (2-phenylethyl GS). Total glucosinolate contents in roots, swollen stems, leaves and floral buds ranged from 2.360 to 20.155μmol·g-1DW,15.544 to 46.052μmol·g-1 DW,35.808 to 96.259μmol·g-1 DW and 79.762 to 130.83lμmol·g-1DW respectively. Floral buds contained the highest concentration, followed by leaves, swollen stems and roots.2-phenylethyl GS and 2-Propenyl GS were the major glucosinolate in roots, accounting for 39.18% and 34.16% of the total root glucosinolates, respectively. The major glucosinolate in swollen stems, leaves and floral buds was 2-Propenyl GS, accounting for 90.24%,93.74% and 92.94% of the total glucosinolates, respectively. Significant differences of total and individual glucosinolates levels were abserved among different organs and varieties. The varieties (08A-124,08A-131,08A-133) showed the highest 2-Propenyl GS or 2-phenylethyl GS content. So, they could be good candidates for future breeding programs. There are also obvious differences in glucosinolate types between four organs. In root, indole, aliphatic and aromatic glucosinolates shared a approximately proportion of total GS content, while the aliphatic glucosinolates were relatively abundant in the other three organs.