PGPRs affected photosynthetic capacity and nutrient uptake in different Salvia species

Abstract

In order to evaluate the effect of plant growth promoting rhizobacteria (PGPR) on photosynthetic capacity and nutrient uptake of three Salvia officinalis species, an experiment was conducted at the Agricultural Research Center of West Azerbaijan during 2015 and 2016. The experiment was conducted in split factorial based on randomized complete block design with three replications. The main plot included three species of Salvia officinalis (hybrid species), S. Sclarea, and S. nemorosa (both native species). The sub plot included the factorial treatment of nitrogen stabilizing bacteria in three levels (Azosprillium lipoferum, Azotobacter, and control), and phosphate solubilizing bacteria in three levels (Pseudomonas, Enterobacter, and control). Eventually, two years were combined into a compound analysis. The evaluated traits included plant height, leaf area, number of flowering branches, photosynthetic pigments (chlorophyll a, chlorophyll b, and total chlorophyll) and leaf nutrients uptake [(nitrogen (N), phosphorus (P), potassium (K)]. The results indicated a significant effect of the studied traits compared to the year (leaf area, number of flowering branches, chlorophyll a, chlorophyll b), cultivar, N stabilizing bacteria (except chlorophyll b) and phosphate solubilizing bacteria (p < 0.01). The effect of quadruple interaction showed a significant effect (p < 0.01) on all studied parameters except of plant height and leaf nutrients. The results indicated that leaf area and number of branches in the second year increased by 24.7 and 28.21%, respectively. The amount of chlorophyll a decreased in the second year, however chlorophyll b increased significantly and total chlorophyll did not change significantly. S. Sclarea produced the highest plant height (102.62 cm) and the highest leaf number (68.16) per plant. Further, the results showed that in all three species, Pseudomonas phosphate solubilizing bacteria had the highest effect on the leaf nutrient uptake and the combination of Pseudomonas with Azotobacter improved the nutrient uptake and the growth status of the plant.