Study On The Physiological And Biochemical Mechanism Of Slow Stripe Rusting Wheat Varieties

Abstract:It is an importance to study some physiological and biochemical criteria of different resistant wheat varieties.The seedling of Four slow stripe rusting wheat varieties, Xiannong 4, Liboliula, Pingyuan 50, Wudubaijian,er, and the seedling of two fast-rusting wheat varieties, Mingxian 169, Ganmai 8, all of them susceptible to Puccinia striiformis f.sp tritici(wheat stripe rust), were grown in the greenhouse. They were inoculated with wheat yellow rust at the first-leaf stage. The uninoculated plants were used as control. The first leaves were taken for physiological analysis from period of chlorosis, period of uredium emergeing widely,period of sporulation flourishing and biochemical analysis from the second day after inoculation to twentith day.The results showed that there were no difference in the content of Chlorophyll (a+b) and Chlorophylla/b in the healthy wheats. Between slow-rusting and fast-rusting varieties, the content of Chlorophyll (a+b) and Chlorophylla/b deduced after inoculation. But the content of Chlorophyll (a+b) were higher in the slow-rusting varieties, the Chlorophylla/b changed similarly in the slow-rusting and fast-rusting varieties,that is to say, the Chlorophylla/b was not characteristics of slow rusting.Photosynthesis and transpiration of diseased leaves and check leaves were measured with LI-6200 Photosynthetic System. The results showed that the data of photosynthesis and code in the period of chlorosis in the inoculated varieties higher than in the check, the cond in period of uredium emergeing widely,period of sporulation flourishing after inoculation were higher than uninoculated varieties,and its of fast-rusting varieties was higher than that of slow rusting. The respitation of different varieties after inoculation was higher than that of uninoculated ones, but transpiration of fast-rusting varieties was higher than that of slow rusting. The cond and transpiration may be the best method to differentiate the slow-rusting from susceptible varieties. The results the variation of some biochemical criteria as follows: There were not obvious difference the activity of POD (Peroxidase) and PPO(Polyphenol Oxidase) in control of different varieties. But the activity of POD and PPO in the inoculated varieties was higher than that of control. In the same time, the activity of POD in the fast rusting varied steadly and slowly, however in the slow rusting ones, the activity of POD varied remarkably, that have significantly increased and deduced. And after inoculation the activity of POD reached a peak value in 4th-9th day in the slow rusting ones, while in the fast rusting varieties, it reached a peak value in 20th day. In the contrary, PPO activity reached a peak value on 4th day in the slow rusting ones, and in the fast rusting ones on 2nd day.The number of PPO isoenzyme bands was same in all varieties. But POD isoenzyme bands were more in the slow rusting inoculated ones than in the control, in the fast rusting ones, it were less than in the control in many parts of time in 2nd-20th day. In 2nd-6th day after inoculation,the POD isoenzyme bands were one to two more in the slow rusting ones than in the fast rusting ones; In 9th day, they were similar in all varietiesï¼›In 15th day , the changes were similar to 2nd-6th dayï¼›In 20th day, they were less in the slow-rusting ones than in the fast-rusting varieties, the color of bands got deeper.