Effect of local strains of nitrogen fixing nodule bacteria on some biochemical parameters of pea plants

Leguminous plants demonstrates cooperation between the processes of photosynthesis and nitrogen fixation. The concentration of pigments depends on the nitrogen supply to plants. Photosynthetic products which are formed in leaves are the main energy source for nodule growth, bacteroid respiration and nitrogen fixation. Influence of seed treatment by nodule bacteria Rhizobium on pigment and starch content in pea plants was studied. Effectivity of rhizobia was evaluated in field experiments which were conducted at three vegetation seasons. In this study we used fast-growing nodules bacteria Rhizobium leguminosarum bv. viciae strains RRL1-RRL12, isolated from pea plants in the Ivano-Frankivsk region. The Rhizobium leguminosarum 245a strain was used as the reference strain based on its efficiency. Pigments were extracted from the pea plants leaves by 96% ethanol. The concentration of pigments was determined by spectrophotometric method. Concentration of starch was measured by colorimetric method which based on formation of colored complex starch-iodine. It was found that concentration of chlorophylls in pea leaves was higher at the budding and flowering stages, in plants inoculated with local strains RRL8 and RRL9 as compared to control and treated with standard strain plants. It seems that these strains can be used in agriculture for the seed inoculation for fixation of air nitrogen to enhance the pea crop capacity. The concentration of chlorophyll a was the highest at the flowering stage in comparison to the previous growth stages of pea plants. At the 4-5 leaves stage, the concentration of starch in plants inoculated with RRL4-RRL6, RRL8 and 245a strains was 38-57% lower compared to controls. This could be related with intensive nodules formation.