Studies On Content, Distribution And Changing Nature Of Lignin In Development And Storage In Radish

Lignins, polymeric natural products arising from an enzyme initiated, dehydrogenative polymerization of one or more phenyl propane monomers, are ingredients of lignifying tissues in plants. Lignins play important roles ii. disease resistance of plants acting as a mechanically protective screen resistant to pathogenic invasion and their enzyme decomposition. In addition, it is reported that lignins have some effects on cancer resistance in human body. A series of physiological and chemical changes taking place in the process of hollowness and storage of radish can lead to deterioration on edible, processing quality and so on. So, it has theoretical and practical importance in deeply studying on lignin and a series of physiological and chemical changes in hollowing and storage of radish. In this experiment, six varieties of different skin color of radishes (WaterRadish, DaHongPao, DuanYel3, TeZao3O, QiuKuiQing, JieShouQing) were selected, and lignin content of leaf, lignin content of different parts of root, different stages of development of root and different parts of different hollowing progression of root of those radishes were studied. At the same time, content of lignin, sugar, water, fiber in storage of three red skin radishes (SiJiHong No. 1, SijiHong No. 3 and ZhongQiuHong) bred by our radish research team were analyzed too. The results showed that, lignin content of second and third leaf increases with the leaf development, and its range is 6. 05% 9. 28% and much more than that of different parts of root. In different parts of root, lignin content of root skin ranging from 12. 42% to 16. 07% is lower than upper and middle root, lignin content of upper and middle root is relatively higher and their ranges are 13. 18% 9.86% and 12. 58% 9. 36% respectively, and range of lignin content of down root is 12.27% 9.22%. Lignin content of root in spring and autumn is different. In spring, lignin content increases with the root development. Lignin content varies slowly from scarified stage to permanent planting tage, increases somewhat from permanent planting stage to shoulder blasting stage, and increases quickly from shoulder blasting stage to harvesting stage. But in autumn, lignin content increases or decreases at some periods of root development. Lignin content varies slowly from scarified stage to permanent planting stage to shoulder blasting stage, and increases just after harvesting stage. With the increase of hollowing progression, lignin content increases, water content decreases, soluble sugar increases first and then decreases. Lignin content of root skin and down root are lower than upper and middle root from 0 hollowing progression to 7 hollowing progression, lignin content of middle root increases quickly when hollowness is serious. Water content of root skin is always lower than other parts, and that of middle part is higher than other parts, upper and middle parts are main parts of losing water in the process of hollowness. Soluble sugar of root skin varies slowly, and that of upper and middle parts are higher than other parts at early stage, but decrease greatly at 7 hollowing progression. In the storage, ligniri content increases gradually and is high correlative to hollowing index, lignin content of root skin is lower than other parts and that of middle part is higher and increases quickly. With development of storage, hollowing index increases. Water content increases first and th...