| Viscum coloratum(Kom.)Nakai is a perennial dioecious plant of Loranthaceae,mainly distributed in Heilongjiang,Jilin,Liaoning,Hebei,Shandong,Anhui,Jiangsu and other provinces of China,and has important ornamental and medicinal value.This study surveyed the four main natural mistletoe populations in Liaoning Prov.,namely in Fengcheng Shalizhai,Anshan Qianshan,Kuandian Yangmuchuan,and Kuandian Huangyishan,focused on investigating the ecological characteristics of these mistletoe populations and the physiological characteristics of their fruits,and analyzed the genes that are in charge of fruit color using related molecular biological method.The results are as follows:(1)There are 4 main species of host tree for V.coloratum in Liaoning,namely pear trees,alder,willow,and poplar,among which the highest parasitic rate occurs in pear trees,followed by poplar.The proportion of male to female individuals is close to 8: 1,and female plants are significantly more than male plants,and the biomass of male plants is smaller than female plants.(2)The morphological characteristics of the female and male plants show significant difference,and compared with the male plants,the female plant height,crown width,and age class are increased by 44.31%,41.65%,and 60.92%,respectively,and the number of leaves is increased by 136.36%(P<0.05).Compared with the male plants,the branch and leaf weights of female plants are significantly increased by205.49% and 125.5%,respectively.The female plant height and total biomass show significant positive correlations with the crown width: The male plants show a linear positive correlation,and the female plants show a power-function increasing tendency.(3)The fruits of V.coloratum have two colors(yellow and red),the ratio of which may have color deviation in the same population.Except the amount of red-fruit V.coloratum in Anshan Qianshan is greater than yellow-fruit V.coloratum,the amounts of yellow-fruit V.coloratum in other three populations are dominant,and the total color ratio of yellow fruit to red fruit in the four species is about 3: 1.(4)The variation coefficients of the fruit longitude diameter,transverse diameter,and fruit shape of V.coloratum are less than 10%,which is a relatively stable botanical trait.The fruit weights have variation among different species,and the variation coefficients range within 13.53%~17%;the leaf length,leaf width,and leaf area have bigger genetic variation among different-color fruits,which are more than 20%,indicting abundant genetic diversity.(5)The fruits with different colors both contain 15 kinds of amino acids(methionine is not detected),including seven essential amino acids for human body,and among these amino acids,the contents of glutamic acid and aspartic acid are higher,and among the seven essential amino acids,the arginine has the highest content followed by the leucine,lysine,and isoleucine.In addition to the arginine,the contents of other amino acids in yellow fruits are higher than those in red fruits,but the total amounts of essential amino acids in red fruits are higher than those in yellow fruits.(6)The contents of crude protein,carotenoid,and vitamin C in the two color fruits show significant difference: the contents of crude protein and vitamin C in red fruits are less than yellow fruits,but the content of carotenoid is higher than yellow fruits,indicating the genetic differences between different-color fruits are relatively large.(7)It is preliminarily confirmed that the fruit color dichotocarpism of V.coloratum is not directly related to the host type but related to the Rose1 gene of the MyB gene family,which regulates flower and fruit colors.This study has laid certain foundation for exploring the ecological characteristics,classification,and system evolution of V.coloratum,and provided more evidence for further understanding the function of the MyB gene family by Chinese and foreign scholars. |
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