Propagation trays were filled with sterile washed river sand
and soaked to semi-submerge level of moisture with a quarter
strength of Hoagland’s nutrient solution (Guimil et al., 2005). Surface
sterilized rice seeds were pre-germinated on water agar for
4 days in dark and then sown into the moist sand. Each treatment
was replicated with 10 plants. One hundred microlitre of
the cell suspension was inoculated to each plantlet. Sterile distilled
water was replaced in control plants. The pots were placed
on cool-white fluorescent lighting shelf, and the plants were
grown at room temperature (28 ± 2 ◦C) and were watered with
sterile distilled water every day. A quarter strength Hoagland’s
nutrient solution was applied to the plants every week and the
plants were grown for 3 weeks after sowing. Plants were sampled
weekly and growth parameters including shoot and root
length and shoot and root dry weight were measured. Total root
length was measured using WinRhizo software. Percentage yeastinduced
root growth response (%YGR) and specific root length
(SRL) were calculated using the following formulas (Cloete et al.,
2009):