Abstract:
Gyrinops walla Gaertn (wallapatta) is a highly valuable agarwood
producing plant species endemic to Sri Lanka. Due to over-exploitation
of the species, the natural habitats are tremendously under pressure,
thus commercial-scale cultivation is needed to meet the increasing
demand. Propagation through seeds is found to be hampered by
inadequate availability of seeds, poor viability and germination and
delayed rooting of seedlings. As the use of Phosphate Solubilizing
Bacteria (PSB) is recognized to be a sound technology that could
enhance the growth of different crops, the present research was carried
out to investigate the effect of isolated five PSB strains on growth and P
uptake of wallapatta seedlings. Significant (P ≤ 0.05) increase in plant
height, stem diameter, shoot and root dry weight of wallapatta plants
were recorded from the seedlings raised with the PSB inoculated seeds
compared to non-inoculated seeds. The best growth performances
(52.67 cm, 7.52 mm, 7.62 g/plant, and 3.89 g/plant for plant height,
stem diameter, shoot and root dry weight, respectively) were recorded
from the seedlings inoculated with the strain PSB5 followed by PSB3.
Significant (P ≤ 0.05) decrease in soil pH and increased available P
contents were recorded in rhizosphere soil samples taken from PSB
inoculated seedlings than that of the non-inoculated seedlings. The
lowest soil pH and the highest available soil P contents (6.05 and 18.24
mg/Kg soil respectively) were recorded from the rhizosphere soils
inoculated with the strain PSB5 followed by PSB3. The strain PSB5
which enhanced the highest growth performances and P uptake of
wallapatta seedlings was identified as Enterobacter cancerogenous.
Therefore, present results provide much needed baseline information
for future studies on the use of PSB as bioinoculants to enhance the
early growth of wallapatta seedlings.
