Biologie unicellulaire

Abstrait

Stress Effect and Development of Leaf-Bridge Bioassay of Dendrobium Sonia-28 Orchid Plantlets Resistant to Fusarium Proliferatum

Raheleh Dehgahi and Alireza Joniyas

Among horticultural and floral crops, orchids are outstanding in their diversity of shape, form and colour. Dendrobium sonia-28 is an important orchid hybrid in the Malaysian flower industry, but suffers from fungal diseases especially those caused by Fusarium proliferatum . Protocorm-like bodies (PLBs) of Dendrobium sonia-28 were subjected to various doses of Fusarium proliferatum culture filtrate (CF), fusaric acid (FA) and gamma irradiation. Results showed that PLBs survival rate were inversely related to the treatment doses as well as experience time. Another main objective of this study was to evaluate degree of resistance among Dendrobium sonia-28 plantlets derived from PLBs treated with CF, FA and gamma irradiation methods. Plantlets obtained from the various treated PLBs were inoculated with a pathogen spore suspension of 10,000 spore/mL. Leaf-bridge bioassay results revealed that leaflets challenged with higher concentrations of CF, FA and gamma irradiation showed less disease symptoms after treatment, indicating that there is a strong relationship between in vivo and in vitro resistance of Dendrobium sonia-28 to infection to Fusarium proliferatum