Studies On Basic Of Physiological And Biochemical Resistance Of Banana To Fusarium Wilt

Fusarium wilt of banana is considered as one of the most destructive worldwide disease of banana , caused by a kind of soil epiphyte , and it is badly endangering the production of banana , especially Fusarium oxysporum f.sp.cubense snyder & Hansen Race4. which arise extensive attentions and researches. In this paper , the physiological and biochemical change of banana cultivars stems were studies after inoculation with banana to Fusarium oxysporum f. sp.cubense by using five banana cultivars including'Gold finger'(highe -resistant),'Williams sport'(middle- resistant),'1282'(endurance-susceptible),'Williams'(susceptible),'TianBao'(susceptible).And the physiological and biochemical resistance mechanism of banana to Fusarium wilt were studied. The results were as following.1,During the growing development those Four defensive enzyme activities including PPO, POD, PAL, SOD andβ-1,3-Glucanse in stems of all banana cultivars were not obviously and fluctuant in a certain scope.2,The PPO activity of resistant cultivars increased after inoculation , while PPO activity was consistent to the level of susceptible cultivars . After inoculation . The content of PPO in resistance cultivars was evidently higher than susceptible cultivars. It can be included that PPO participated in the activity of Fusarium wilt of banana preliminarily.3,Results showed that the activity of PAL and POD of all banana cultivars increased after inoculation of Fusarium oxysporum and resistant resistant cultivars had higher increasement rate and peak value of PAL and POD than susceptible cultivars. The enzyme activities of PAL was more susceptive than POD . The results showed that the variety of activity of PAL and POD had close relations with the resistance to Fusarium oxysporum of banana .4,The results showed that the activity of SOD in stems of all banana cultivars was affected after inoculation. The results showed that the change of enzyme active of SOD in stems of all cultivars were turbulent and were absence of orderliness after inoculation . And if SOD participated in the activity of Fusarium wilt of banana needs more studies5,Theβ-1,3-Glucanse enzyme activities of banana cultivars were not quite , but the activity of Theβ-1,3-Glucanse of all banana cultivars of changes after inoculation .It were in stems of resistant cultivars decreased at first , then ascended , but the Theβ-1,3-Glucanse enzyme activities of the resistant cultivars were significantly rigging faster and greater than susceptible cultivars . It can be included that Theβ-1, 3-Glucanse enzyme participated in the activity of Fusarium wilt of banana preliminarily.6,During the growing development the lignin content in stems of all banana cultivars were differ significantly , the resistant cultivars of lignin content higher than that of susceptible cultivars . Fusarium wilt of banana could induce the accumulation of lignin in stems of banana . However , the total amount and the rate of accumulation varied with the resistance of cultivars . The accumulation of lignin in resistant cultivars were faster and greater in comparison with those in susceptible cultivars . These results indicated that there were very significantly positive correlation the accumulation of lignin in stems to Fusarium wilt .7,The total phenolics contents in stems of all cultivars increased after inoculation. The total phenolics contents in stems of all cultivars were always higher than those of CK after inoculation. It can be included the total phenolics participated in the activity of Fusarium wilt of banana a preliminarily .8,The Malondiadehyde contents appeared one peaks. The Malondiadehyde contents of Williams, TianBao, 1282 in stem were higher than Gold finger, Williams sport .The Malondiadehyde contents were related with the cultivars'resistance.9,The banana of susceptible cultivars of free amino acid content higher . It may be associated with the free amino acids which provided nutrients for pathogenic bacteria during the process of banana resistant to Fusarium wilt of banana .10,There was very significantly positive correlation between disease indexes of Fusarium wilt and several enzyme activities including PPO , POD and PAL as well asβ-1,3-Glucanse in these five banana cultivars after inoculation . The lignin and total phenolics content of banana were related to its resistance of Fusarium wilt significantly . Malondiadehyde and free amino acid content of banana were related to it resistance of Fusarium wilt was very significantly negative correlation . The results suggested that it could be used as one of indexes for resistance estimation of banana to Fusarium wilt .