Allelochemicals Biologica... - Name

200
CHUIHUA KONG
(a) (b)
Figure 5. Inhibitory activities of flavone, cyclohexnone and mixture with low polarity against
spore germination of (a) P. oryzae and (b) R. solani at different concentrations.
Table 3. Chemical constituents of the mixture with low
polarity isolated from rice leaves
Retention time (min) Chemical constituents Relative amount (%)
1.89 2-methylhexane 8.77
5.40 4,6-dimethylundecane 2.48
6.28 2,2,6-trimethyldecane 2.35
7.26 2-hexyl-1-decanol 2.11
7.58 1-butyl-2-propylcyclopentane 8.45
8.19 2,6-dimethyl-decahydronaphthalene 22.45
8.40 trans, trans-1,10-dimethylspiro[4,5]decane 8.03
8.48 2,3-dimethyl-decahydronaphthalene 3.37
8.63 trans, cis-1,8-dimethylspiro[4,5]decane 8.19
8.78 1,2-dimethyldecahydronaphthalene 11.49
9.10 cis, cis-1,1-dimethylspiro[4,5]decane 11.60
10.18 1,4,6-trimethyl-1,2,3,4-tetrahydronapthalene 1.77
14.35 hexadecanoic acid, methyl ester 1.85
- Other unknown components* 7.09
*A total of 11 components and their relative amounts was less than 1% of the mixture with low
polarity
Alkylresorcinols (Figure 6) are another kind of antifungal agent that were isolated
and identified from etiolated rice seedlings (Suzuki et al., 1996; 1998). Antifungal
activities of alkylresorcinol against spore germination of P. oryzae were correlated
with their concentration and structure, but complete inhibition of their spore
germination occurred only at a concentration of over 100.g.ml -1 .