-20-
Abstract
This study was aimed to apply chitosan for protection of Lady,s slipper orchid (
Paphiopedilum
niveum
) from fungal diseases. Six species of local mushroom
Schizophyllum commune, Volvariella
volvaceae
.,
Auriculalia
sp.,
Lentinus connatus
Berk.,
Pleurotus sajor-caju
, and
Pleurotus ostreatus
.
were extracted and about 2-9 % of chitosan (% DD>80 %) was obtained. The molecular size of these
mushroom chitosans were in the range of 0.34-5.78x10
5
Da. The orchid plants were treated with 10 and
100 ppm of each mushroom chitosan at 5 day interval for 24 weeks. The result showed that these chitosans
could increase the orchid leaf length 1.3-1.8 fold longer than the control. Moreover, the activation of PR
proteins (Pathogenesis related protein) such as peroxidase, superoxide dismutase, chitinase and
B
-1,3-
glucanase activities were detected from the leaf extracts of chitosan treated plants. Necrosis test on orchid
leaves treated with S.
commune
and P.
sajor-caju
chitosans indicated the resistance of the plants against
Fusarium
sp.,
Curvularia
sp. and
Phythophthora
sp. Further elucidation of PR proteins function might be
benefit for application of local mushroom chitosans for fungal disease control in orchids and other
plant species.
Key words :
chitosan ; PR Protein (Pathogenesis related protein) ; mushroom ;
Paphiopedilum niveum
.
