This study aimed to evaluate, at 15, 20 and 25 ºC, the physiological potential and enzyme activity of seedlings from six samples of rice seeds stored for one year and treated with growth-promoting rhizobacteria (Pseudomonas synxantha) and the bioactivator thiametoxam. The following were evaluated: seed germination, first germination count, root protrusion speed index, emergence percentage and emergence speed index, shoot and root length and enzyme activity (esterases, α-amylase and peroxidases) at 15, 20 and 25 ºC. In these conditions, thiametoxam and the rhizobacteria P. synxantha (DFs 185) improved the physiological performance of rice seeds with physiological qualities at low temperatures (20 and 15 ºC) and did not change the expression of the esterase and peroxidase isoenzymes. The rhizobacteria P. synxantha (DFs 185) increased the expression of the enzyme α-amylase at low temperatures.
Oryza sativa L.; bioactivator; Pseudomonas synxantha; cold temperatures