Studies On Mechanism Of Nitrogen And Phosphorus On Isoflavones Contents In Red Clover (Trifolium Pratense) And Anti-oxidant Performance Of Isoflavones

Via studying the influence mechanism of nitrogen and phosphorus on isoflavones contents in Trifolium pratense and anti-oxidant mechanism of isoflavones, main conclusions were as follows:1. At each growing stage, although four isoflavones components were different, BioA content was the highest and Formononetin (For) was the second. Bigger differences existed in isoflavones content among different parts of red clover; the highest contents (8103.3ug/g) obtained in leaves and it accounted for 50 percent of the whole plant; isoflavones content in flowers was 7130.1ug/g and it accounted for 45 percent; And isoflavones content in the stems was the lowest (737.3ug/g) and it only accounted for 5 percent. This demonstrated that during the development of red clover, different organs had isoflavoids metabolization and isoflavones distribution was different in different organs.2. Isoflavones contents were lower at jointing and bud-appearing stages and there were no appearent changes during this period. From bud-appearing stage, isoflavones contents increased quickly. Complex change tendency of high-low-high-low appeared at the stages of early flowering, full flowering, budding and mature. Higher isoflavones contents obtained at early flowering and budding stages.3. At different growing stages, N and P fertilizing rate had huge influence on isoflavones contents in Trifolium pratense cv. Minshan. With the increasing of N and P fertilizing rates, isoflavones contents had a change tendency of increasing firstly and decreasing then. The highest isoflavones contents obtained under the treatment of A3 (100 kg N /hm2) and B2 (120kg P2O5/hm2).4. PAL, SP, SS and MDA were very important for isoflavones synthesis. While PAL had higher activity and SP and MDA content increased, it led the increasing of Phenylalanine and promoted isoflavones synthesis. Thus at different growing stages and P fertilizing rates, PAL, SP and MDA were significantly positively correlated with isoflavones content and SS was negatively correlated with it. At different N fertilizing rates, PAL, SS and MDA were significantly positively correlated with Isoflavones content and SS was negatively correlated with it. There were no consistent correlations among SS, SP and isoflavones content at different growing stages, N and P fertilizing rates, so synthesis mechanism of isoflavones need to be studied further.5. There were any relations between anti-oxidant performances of isoflavones and three activity enzyme (POD, CAT and SOD). At different N, P application rates, activities and isoflavone content were negatively correlated. It showed that anti-oxidan system in red clover was an integrated overall. Isoflavones content could make up the decreasing of anti-oxidant enzyme and insured the normal growth of plants. At different growing stages, with the develpoment of Trifolium pratense cv. Minshan, POD activity and isoflavones content decreased firstly, increased after bud-appearing stage and remained unchange after early flowering stage; Isoflavones content was positively correlated with POD. At the whole stages, CAT activity had"low-high-low"change tendency and isoflavones content was positively correlated with CAT activity; activity had"V shape"change tendency and isoflavones content was positively correlated with SOD activity. Under different N and P fertilizing rates, isoflavones content was negatively correlated with POD, CAT and SOD activity. SOD in the whole period of reproductive activity rules form a not very standard "V"-shaped, isoflavone content and it was a significant positive correlation. There were no consistent correlations among isoflavones content and each index at different growing stages, N and P fertilizing rates, so synthesis mechanism of isoflavones need to be studied further.