Ümmügülsüm Erdoğan

Enzyme activities and growth promotion of spinach by indole-3-acetic acid-producing rhizobacteria

Summary The objective of this study was to evaluate the effects of twelve plant growth-promoting rhizobacteria (PGPR; Bacillus mycoides FD07, B. sphaericus RC12, B. pumilus RC19, B. cereus RC18, Variovorax paradoxus RC21, Paenibacillus polymyxa RC35, Pseudomonas putida RC06, B. megaterium RC07, B. megaterium M-3, B. licheniformis RC08, B. subtilis RC11, and B. subtilis OSU-142) used as biofertilisers, on various enzyme activities [glucose-6-phosphate dehydrogenase (G6PD); 6-phosphogluconate dehydrogenase (6PGD); glutathione reductase (GR); and glutathione S-transferase (GST)] and on seedling growth in spinach (Spinacia oleracea L.). Enhanced plant growth could result from rhizobacterial production of indole-3-acetic acid (IAA). The highest IAA-producing rhizobacteria (RC35 and RC06) produced the highest root and shoot weights. PGPR improved N and P nutrition in spinach, and therefore stimulated plant growth and key enzyme activities. The responses to inoculation, compared to uninoculated control plants, were: –1.9% to +36.4% for shoot fresh weights (FWs), –5.5% to +30.1% for root FWs, –3.5% to +29.8% for shoot dry weights (DWs), –3.8% to +38.5% for root DWs, and –5.9% to +30.1% for leaf areas. Plant growth responses were variable and dependent on the inoculant strain used, as well as on the enzyme activity and growth parameter being evaluated. Close correlations between plant shoot growth, PGPR inoculation, and G6PD (r = 0.28*), 6PGD (r = 0.55**), GR (r = 0.73**), and GST (r = 0. 64**) enzyme activities in spinach have been demonstrated.

Role of inoculation with multi-trait rhizobacteria on strawberries under water deficit stress@@@Augimą skatinančiomis rizobakterijomis inokuliavimo įtaka braškėms esant vandens stygiaus stresui

This study was conducted during 2011 and 2012 to evaluate the effect of 1-aminocyclopropane-1-carboxylate (ACC) deaminase-containing, N2-fixing and P-solubilizing bacteria on the yield and morpho-physiological parameters of strawberry. A total of 8 applications at the trial set, with four water regimes were randomly distributed into the pots. The diminishing water supply caused a gradual decrease in the plant growth, chlorophyll content and berry yield, accompanied by increasing activities of drought stress markers such as total phenolics content (TPC), trolox equivalent antioxidant capacity (TEAC), malondialdehyde (MDA) content, hydrogen peroxide (H2O2), glutathione reductase (GR), glutathione S-transferase (GST), catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and ascorbate peroxidase (APX) in the leaves of strawberry. The multi-trait bacteria also increased plant growth and yield as well as TPC, TEAC, antioxidant enzymes (GR, GST, CAT, POD, SOD and APX) activity, phytohormone (GA, SA and IAA) and the contents of N, P, K, Ca, Fe, Mn, Zn and Cu, but decreased MDA and H2O2 contents which may contribute in part to activation of physiological and biochemical processes involved in the alleviation of the effect of drought stress.

Effects of Root Plant Growth Promoting Rhizobacteria Inoculations on the Growth and Nutrient Content of Grapevine

ABSTRACT The objective of this study was to evaluate the effects of seven nitrogen (N2)-fixing and/or phosphorus (P)-solubilizing and siderophore-producing microorganism based bio-fertilizers in single and triple strain combinations isolated from the acidic rhizospheric soil of native tea, grapevine, and wild red raspberries. As a result of this study, bacterial efficiency was found to be variable and depended on the bacterial strains and evaluated growth parameters. Plant growth-promoting rhizobacteria (PGPR) has improved macro- and micro-nutrient concentrations in grapevine leaves, and stimulated plant growth. Triple inoculation and single inoculation based bio fertilizers were found to stimulate overall plant growth, including shoot and leaf weight, main shoot length, leaf ground index, chlorophyll, nitrogen, zinc and iron content of grapevine cv ‘Italy’. Bio-fertilizers increased the nutrients such as nitrogen, zinc and iron concentrations and consequently increased the chlorophyll content of the leaves.