Studies On The Resistance To Grapevine Downy Mildew And Resistant Mechanism Of Wine-making And Table Grapevine Varieties In The Helan Mountain Eastslope Of Ningxia

The grapevine downy mildew,[Plasmopara viticola (Berk.et Curt.)Ber.et de Toni] distributes all grapevine production areas in the world.It isone of the most important fungi diseasea,which damages the grapevine,leads to a serious economic loss to grapevine production.In resentyears,the diseasa occurs in Ningxia grapevine productive areas seriously,which must be controlled.The studies on field resistance to grapevinedowny mildew and resistant mechanism of wine-making and tablegrapevine varieties in the Helan Mountain east-slope of Ningxia,throughfield investigation,indoor analyses,obtained the results as follows: Through field investigation and experinent of indoor inoculation,theresults showed that all varieties,including wine-making and tablegrapevine,were infected by grapevine downy mildew,but the resistanceshad difference between wine-making and table grapevine,infective typeranged from 2(HR) to 4(HS),the wine-making varieties are 2,the tablevarieties of grapevine are 3 and 4.wine-making grapevine varieties aremore resistant the table grapevine varieties.The study on lignosetechnique showed that lnhibiting effects of the secretion in surface of leafof grapevine to germination of sporangia have'nt a significant difference. The resistance to the disease of different grapevine varieties reflectedexistence of its resistant gene and speed,degree and quantity of resistantsubstance that the gene expressed.The results of analyses on relationshipbetween chitinase,β-1,3-glucanase,PO,PPO in leves of grapevineinfected by Plasmopara viticola and the disease showed that the pathogenof grapevine downy mildew can derive accumulation of these enzymes,but accumulated speed and quantity of these enzymes existed asignificant difference between resistant varieties and susceptiblevarieties,,increase in activity of these enzymes in resistant variety,Cabernet Sauvignon were faster and higher than those on susceptiblevarieties,hongti,Zana,Longyang,and the time of keeping high activityof these enzymes were longer than others. The relationship between matabolisem of phenylalanine and resistanceof plants to diseases was significant .These varieties of differentresistances were infected by Plasmopara viticola,the content of PAL,chlorogenic acid and lignin in the resistant variety, Cabernet Sauvignonwas longer than those in susceptible varieties. The results of analyses of peroxidase isozymes showed that theactivity of enzymes in all varieties infected by p.viticola increased,butthe quantity of enzymatic belt,enzymatic colour are more and deeper inthe resistant variety, Chit izzhu than that of susceptible variety, Longyan,but the quantity of enzymatic belt decreased,the colour of enzymatic beltpaled in resistant and susceptible varieties in company with increase ofdisease degree.