| Inhibition rates of Bacillus subtilis, strains BS-208, BS-209 and BS-21, Bacillus cereus, strain BC-01 against Botrytis cinerea were tested by dual culture on potato dextrose agar. Results showed that inhibition effects of 4 strains were 78.06%, 82.49%, 75.74% and 73.84%, respectively. The protective and curative effects of Bacillus subtilis BS-208, BS-209, BS-21 and Bacillus cerus BC-01 against B. cinerea were assayed in vivo under greenhouse conditions. Control efficacies of preparations of strains BS-208 and BS-209 were also assayed against B. cinerea in the field in 2002 and 2003. The greenhouse experiment result showed that the fermentation liquid and spore of strains BS-208 and BS-209 had control efficacy above 75% with inoculating after 24 and 48 hours, but the filtrate had poor control efficacy. Result of two years field experiment in the field indicated that preparations of strains BS-208 and BS-209 could effectively control tomato gray mould. The control efficacy became better with the increasing of concentration and 800-fold treatment showed the best control efficacy. After three times treatment with the 800-fold preparation continuously, the control efficacy reached above 74% and effect of strain BS-208 was better than that of BS-209.The result of biochemical characters of strains BS-208 and BS-209 showed that the characters of two strains were basically consistent. The growth curve of the two strains was assayed, results showed that the time of strain BS-208 and BS-209 reached the highest amount in PDB liquid media were 24 hours and 28 hours after cultivation respectively and both of the two strains could form spore 48 hours after cultivation. Two strains could be cultured together with diniconazole, thiophanate-mthyl,carbendazim, triadimefon, polyoxin, imidacloprid, phoxim, abamectin, beta-cypermethrin and fipronil with the maximal concentrations used in field. Mancozeb could inhibit entirely the growth of strains BS-208 and BS-209.Inhibition effects of strains BS-208 and BS-209 to B. cinerea were tested by means of mycelium growth inhibition method. The filtrate of strain BS-208 could inhibit mycelium growth of B. cinerea with inhibition rate of 49.58%. The inhibition efficacy of strain BS-209 was poor. Two strains were tested for their effects on conidia germination of B. cinerea. After diluting 10-fold fermentation liquid of strains BS-208 and BS-209 the suppressive rate of spore germination were 93.45% and 92.35%. No formation of appressorium was found.Colonization and conduction of antagonist B. subtilis strains BS-208 and BS-209 on phylloplane and inside of tomato body were studied by using mutant strains of BS-208 and BS-209 resistant to rifampicin under greenhouse and field conditions. Within 24 hours after injection on the stem, target bacteria were isolated from all parts of tomato body. Results showed that population of strain BS-208 in greenhouse and field were 11 x 108~5.6 x 108cfu/g and 15 x 108~0.02 x 108cfu/g fresh weight respectively, whereas that of strain BS-209 in greenhouse and field were 222 x 106~55 x 106cfu/g and 205 x 106~0.48 x 106 cfu/g fresh weight, respectively. Impression observation method result showed that strain BS-208 and BS-209 could colonize on the leaf surface and the colonization ability of BS-208 was better than that of BS-209. Scanning electron microscopy observation exposed that strain BS-208 distributed asymmetrically on phylloplane of tomato and most of them colonized near the wound, in the sunken place and the base of floss.Induction of systemic resistance and related enzymes activities of superoxide dismutase (SOD), peroxidase (POD), polyphenoase (PPO) and phenylalanine ammonia lynse (PAL) by inoculation of BS-208 fermentation and B. cinerea were studied. Results indicated that activities of PAL and POD reached the maximum 48 hours after inoculation, while that of PPO reached the maximum 96 hours after inoculation.The stability of filtrate of BS-208 was measured after being treated at different pH values and temperatures. Results showed that it... |
PDF Full Text Request