Abstract

The effect of selected plant growth promoting rhizobacteria (PGPR) on growth,chlorophyll content, nutrient uptake and yield of lettuce under salt stress was investigated. The study was conducted in pot experiments. Seeds were coated with suspensions of Bacillus subtilis, Bacillus atrophaeus, Bacillus spharicus,Staphylococcus kloosii and Kocuria erythromyxa, which were isolated from highly salty soils. Pots were irrigated with NaCl solutions of 0, 50 or 100 mM. Salinity negatively affected growth and chlorophyll content of lettuce; however, PGPR treatments positively affected growth parameters such as head weight, head height, root diameter and chlorophyll content compared to non-treated plants that were challenged with salt stress. Leaf number was affected by neither salt nor PGPR treatments. Nutrient contents of the leaves of lettuce plants were significantly affected by salt stress and PGPR treatments. All nutrient element contents investigated were significantly decreased except for Na and Cl under salt stress. PGPR under salinity conditions usually increased plant nutrient element contents of the leaves. It can be concluded from the study that treatment with PGPR can ameliorate the deleterious effects of salt stress on nutrition and on the growth parameters of lettuce plants under salinity conditions.

Key words: Plant growth promoting rhizobacteria, plant nutrient, salinity stress, lettuce.

Abbreviation

PGPR, Plant growth promoting rhizobacteria; SSL, soil salinity levels.