Abstract:
Arbuscular mycorrhiza fungi (AMF) are soil microorganisms, which are
widely recognized to improve plant nutrition by being able to access soil
spaces and nutrient sources. They are obligate symbionts and Salinity is a
major abiotic threat affect soil all around the world. Cymbidium bicolor is an
orchid, found as epiphytes on Palmyrah (Borassus flabellifer) collected from
Mattuwil, Jaffna peninsula. The AMF association in the C. bicolor roots helps
to survive through salinity stress. Therefore, this investigation was carried out
to evaluate mycorrhizae performance under different salinity levels. For the
isolation and identification of AMF, Potato Dextrose Agar (PDA) media was
prepared along with salt solution as a salt PDA media. The root samples of C.
bicolor were subjected to surface sterilization. They were then transferred to
PDA media and allowed for incubation under room temperature for two days
using Complete Randomized Design with four replicates. Growth rate was
measured. SAS software package was used to analyze the data. The fungus
associated with the C. bicolor was Glomus spp. It produced a smooth irregular
white colony initially and later turned to dark green. They grew well in PDA
media. In salt PDA media, AMF had a gradual growth in 140dSm-1
salt
concentration and early-stage (5th day after inoculation), significant growth
was observed in 170dSm-1
and 200dSm-1
compared with 140dSm-1
. But late stage growth was decreased in 170dSm-1
salt and 200dSm-1
salt. Overall, the
significant growth observed in 170dSm-1
salt compare with other
concentrations. Results indicate that AMF has significant growth in saline
condition, which proves the ability of AMF tolerance to salinity stress.
