Studies On Physiological Characteristics, Pathogenicity Of Phomopsis Vexans And Resistance Of Eggplant To Eggplant Phomopsis Rot

Phomopsis rot was a serious disease threatening eggplant production all along. It cancause much yield loss. In this paper , different isolates of Phomopsis vexans were theresearch objects and fruit resistance identification of different eggplant cultivars toPhomopsis vexans were studied. The results were as follows :1 Study on the physiological and ecological characteristics There were two type condia .one is α- type, another is β- type .The condium type wasvery different in fruits leafs and stalks. There are two varieties in fruits and α- type in leafand β- type in stalks. Three isolates of Phomopsis vexans were tested on 9 culture media. Among test media,the OA medium was suit for producing spore and the PSA medium is better than others ongrowth rate. That two kinds of media could be used in fostering and serving Phomopsisvexans in lab. The effects of different carbon sources on Phomopsis vexans were different. Thebetter carbon sources were sucrose , maltose and glucose. The worst carbon source waslactose . Phomopsis vexans could utilize various kinds of nitrogen, which included NaNO3 and KNO₃ . The worst nitrogen sources was (NH₄)₂SO₄ . There was a wide range of pH value for Phomopsis the mycelial growth of vexans .Diverse isolates could survive pH value from 3 to 11.The colony diameters achievemaximum when the pH value was 7. Phomopsis couldn't grow when pH value was lowthan 3. The growth optimum temperature ranged from 25℃ to 30℃ Phomopsis vexans grewbest at 28℃. Phomopsis vexans could not survive both at high temperature such as 35℃and at low temperature such as 10℃. There were no obvious differences among diverseisolates . Under three different light conditions , nature light was the best light condition thatsuitable for the mycelia growing ,the worst condition was continuous darkness.2 Study on enzyme activity of Phomopsis vexans PPO enzyme activities of three isolates were similar, but the laccase enzyme of diverseisolates appeared differences. Maybe it reflected the physiological differentiations ofdiverse isolates. HA appeared one peak after 7days culture. HB had a small peak after 7days and a big peak after 13 days. HY had no peak but it rose gradually after 4 days.3 Electrophoretic analysis Phlyacrylamicide gel electrophoretic analysis of isozymes of 3diverse isolates ofPhomopsis vexans . Three kinds enzymes were Esterase Polyphenoloxidase (PPO) andPeroxidase(POD). The results showed that activity of esterase was high in every isolates .The bands per zone in the gel were clear and the number of bands was more than otherisozyme comparatively. HA had 3bands, HB had 2 bands and HY had 4 bands. So thatelectrophoresis of esterase isozyme analysis might be useful for distinguishing parallelspecies of Phomopsis vexans.4 Resistance identified 13 eggplant cultivars were divided into 3 groups. Resistant cultivar group had 4cultivars. Middle susceptible cultivar group had 5 cultivars and susceptible cultivar grouphad 3 cultivars.5 Study on the enzyme activity of eggplant The results of studies on enzyme activity of PPO POD and PAL at different distancefrom the spot were showen that the enzyme activity of PPO of resistant cultivars ascendedand susceptible cultivar descended. Diverse isolates had different pattern. Changes ofenzyme activity of POD of resistant cultivars were not clear. Enzyme activities of POD ofsusceptible cultivar were descended at first. but it ascended then. This appearance had notconcerned with the isolates' difference. The results of study on two enzyme activities of the host at different day were asfollows: Enzyme activities of POD of all cultivars were ascended. But resistant cultivarshad a peak and the peak was affected by diverse isolates. Middle-susceptible cultivar hadtwo peaks and the second peak value was higher than the first. The susceptible cultivar hadone peak and the extent of enzyme activity of CK of susceptible cultivar was small.Different cultivars had different appearances of PPO enzyme activities, resistant cultivar'senzyme activity had been des...