Variation Of Nutrition Profile And Chromosomal Karyotype In Different Types Of Leaf Beet (Beta Vulgaris Var.cicla)

Leaf beet(Beta vulgaris var.cicla)is a common vegetable in summer of Southwest China.It is popular with consumers for the ability of clearing away heat and toxic.However,there are few studies on leaf beet in all aspects.Leaf beet has a variety of phenotypes and genetic types.Usually,they are classified according to the colors of petioles and leaves by people.What's the different in nutrition and chromosome among different types of leaf beets are not clear at present.In this study,the leaf beet with white petioles,green petioles,red petioles green leaves and red petioles red leaves were used as materials to determine the composition of sugar,carotenoids and phenolics,and the content of ascorbic acid,anthocyanins,proanthocyanidins,flavonoids,polyphenols,etc in leaves and petioles.We evaluated the varieties better in some respects,as well.The differences of different types of leaf beets in various nutritional indicators were also compared.Furthermore,the karyotype analysis of leaf beets was carried out at in our study.The results of the study identified the composition of phenolics in leaf beet for the first time,and analyzed the differences between leaves and petioles also among young leaves,old leaves,tender petioles,old petioles in nutrient content.In addition,the karyotypes of 20 varieties of leaf beets were identified.Our study promoted the development of utilization,classification,and genetic evolution of leaf beet and provided a suggestion for consumers.The major results of our study were as followed.1.The content of many antioxidants and the antioxidant capacity in leaves were found to be higher than in petioles.The ‘BJT' was evaluated as a good sales product with the deep leaf color,the high content of sugar,and the strong antioxidant capacity.‘LJL' with the highest content of phenolics and ascorbic acids,and ‘XD' with high content of carotenoids and phenolics were evaluated as good breeding materials.It was found that different types of leaf beets were more obvious in vitamin C,proanthocyanidins,anthocyanins,flavonoids,phenolics,carotenoids and antioxidant capacity.2.The composition and content nutrition between the young leaves,old leaves,tender petioles and old petiole of leaf beet were also determined.It was found that there are obviously diversity between young leaves,old leaves,tender petiole and old petiole in the composition and content of nutrients.Such as the glucose content,was expressed as young leaves > old leaves,tender petioles > old petioles,and sucrose was just on the opposite.3.The karyotypes analysis of leaf beet were taken.Results showed that the leaf beet was diploid and the number of chromosomes was 2n = 2x = 18 with a pair of satellites.The chromosomes were mainly consisted by metacentric chromosome(m)and submetacentric chromosome(sm).There is no significant differences of the karyotypes found between the four types of leaf beets.The karyotypes are 1A except for ‘Lifeng' and ‘Huaguan',which are 2A.The karyotype asymmetry index(As.K)is from 55.25% to 61.32%.It is a relatively primitive species,and the evolutionary relationship is red petioles green leaves < white petioles < green petioles < red petioles red leaves.