Effect of fluorescent pseudomonads with ACC deaminase activity on micronutrients concentration, root weight and biological yield of rice (Oryza sativa L.) under salinity stress

Soil and water salinity is the major limiting factors for plant growth and crop production. Water and soil salinity almost limit plant growth through increasing osmotic pressure, specific toxicity of some ions such as sodium and color, and nutritional imbalance. In addition to, salinity stress reduces root and plant growth via increasing hormone level. One of the strategies to deal with salinity is inoculation of seeds with plant growth-promoting rhizobacteria (PGPR).

Soil and water salinity is the major limiting factors for plant growth and crop production. Water and soil salinity almost limit plant growth through increasing osmotic pressure, specific toxicity of some ions such as sodium and color, and nutritional imbalance. In addition to, salinity stress reduces root and plant growth via increasing hormone level. One of the strategies to deal with salinity is inoculation of seeds with plant growth-promoting rhizobacteria (PGPR).

The effect of four strains of Fluorescent pseudomonads on uptake of micronutrients in rice was studied under saline irrigation. Greenhouse tests were performed as factorial experiment in a completely randomized design with four replications. First factor was salinity water in five levels (0.7, 1.4, 2.8, 4.2 and 5.6 ds/m originated from sea water) and the second factor was pseudomonads strains (Pseudomonas putida 4, 11 and 108, and Pseudomonas fluorescens 169 and a non-inoculated control). Root of rice (cv. Tarom) transplants was inoculated with mentined strains before planting in pots. During growth period, the pots were irrigated with the abovementioned saline water upto saturation point. In the flowering stage, flag leaf samples were collected to determine Manganese, Iron, Zinc and copper concentration. The content of micronutrients in seed samples was also measured.

The results showed that increasing the salinity level significantly reduced all microelements contents in the leaf and seed. Rice inoculation with different strains of P. fluorescens and P. putida affected on nutrients concentrations under saline irrigation and it increased content of the elements compared to control. Also, the interaction of Pseudomonas strain × salinity level had a significant effect on copper and iron concentration in leaf, and copper and Manganese concentration in seed (P < 0.01). At all salinity levels, maximum iron concentration observed by inoculation of roots with P.fluorescent 169.

Inoculation of rice with various strains of bacteria Fluorescent pseudomonads and putida affected the concentration of micronutrients under saline water irrigation in rice and caused to increase these elements more than control. Therefore, in saline conditions, using strains of Fluorescent Pseudomonas can be growth up of rice plant.