Effect of Pseudomonas fluorescence strains and humic acid on some morphological ‎and physiological characteristics of marshmallow (Altheae officinalis L.) ‎

In order to investigate the effect of plant growth promoting rhizo-bacteria (PGPRs) and humic acid on some morphological and physiological characteristics of marshmallow (Altheae officinalis L.) a pot experiment was carried out under greenhouse condition at Faculty of Agriculture, University of Birjand, in 2017. The experiment was conducted using a complete randomized blocks design based on factorial arrangement with three replications. First factor was seed inoculation with strains of Pseudomonas fluorescence bacteria at four levels (non- inoculation, inoculation with strains 51, 79 and 163) and second factor was humic acid at four levels (0, 150, 300 and 450 mg/kg soil). Results showed that Pseudomonas fluorescence strains and humic acid had significant effects on morphological and physiological measured traits. The most effects of inoculation created by strain 163 of Pseudomonas fluorescenss bacteria and it increased leaf dry weight, leaf area, leaf chlorophyll index, carotenoids and protoin leaf compare to control. The result also showed that increasing of humic acid concentration up to 150 mg/kg of soil increased, leaf area, leaf chlorophylls index, chlorophyll fluorescence index and protein leaf compare to control. Combination use of Pseudomonas fluorescenss bacteria (strain 163) and humic acid (150 mg/kg soil) had the most effect on increasing of leaf fresh weight, leaf area, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids and phosphor leaf compare to control. Due to these results, application of biological fertilizers containing Pseudomonas fluorescence and humic acid can improve morphological and physiological characteristics of marshmallow.