ABSTRACT
In order to study antifungal ability of extracts from Ginkgo,Cinamomum
camphora,Dandelion, Morning glory,Pharbitidis Seed,Oleander by different solvents
and different extract methods on Botrytis cinerea and Monilinia fructicola, the toxicity
action of plant extracts to B. cinerea and M. fructicola were evaluated by using mycelial
growth rate method at the extracts concentration of 20mg/mL in vitro. To explore the
antimicrobial activity of the selected plant extract on B. cinerea,M. fructicola and the
modes of action. The best inhibiting effect extracts was evaluated by spore germination
on slide glass in vitro. Penetrability of cell membranes, mycelial leakage of sugar,
protein and cell wall degrading enzymes was tested by liquid cultivates method. In
addition, the effects of the selected plant extract on disease incidences、lesion diameters
and enzymes activity which related with disease resistance were tested in vivo. The
main conclusions are as follows:
1. As far as antifungal activity was concerned ,the antifungal activity of every
method extract was similar by the same solvent,but interval oscillation method were a
little better. At concentration of 20mg/mL, all of them had ability to inhibit the mycelial
growth of B. cinerea and M. fructicola, and the inhibitory rate of cinamomum camphora
leaves extracts by petroleum ether, cinamomum camphora extracts leaves by ethyl
acetate, Cinamomum camphora leaves extracts by 95% ethanol and Dandelion extract
by ethyl acetate had more than 70% on all tested fungi, especially, the extracts of
cinamomum camphora leaves by petroleum ether had the best inhibiting effect above
90%. By line regression, cinamomum camphora leaves extracts by petroleum ether had
best antifungal ability to B. cinerea and M. fructicola, 50% of effective concentration
(EC50) were 1.89 mg/mL and 2.99 mg/mL。
2. The cinamomum camphora leaves extracts concentration higher 5mg/mL had
good antifungal properties; they all have more than 70% inhibiting rates to the spore
germination of 2 kinds of fungi. At the concentration of 20mg/mL, the extracts of
cinamomum camphora leaves had more than 90% inhibiting rates. At the concentration
of 10mg/mL, the extracts of cinamomum camphora leaves also showed good antifungal
properties but with less extent, they all had more than 80% inhibiting rates.
3. At the concentration of 20mg/mL, The cinamomum camphora leaves extracts
could disrupt the penetrability of cell membranes that resulted in the increase of soluble
sugar, protein and electrolyte in liquid cultivate, and inhibit the cell wall degrading