Enhancement of Some Physiological Parameters in Wheat Plants Affected by Zinc Foliar Application and/or Bacterial Biological Bio-fertilizers

Sterilized sandy soil was used in a pot experiment (irrigatedwith nutrient solution), in which wheat grains Triticum aestivum weregrown for 60 days in green house controlled conditions. Zinc wassprayed at levels (0, 25, 50, 100 and 200 ppm) after 25 and 40 days onwheat leaves. Bacterial isolates were added in soil at root zone.Applying biofertilizers Azotobacter and/or Azospirillum could enhancewheat physiological response in presence of zinc foliar applicationparticularly at 25 and 50 ppm more than at 100 and 200 ppm. Thisresponse was more obvious when using both biofertilizers than usingeach alone. Elevated zinc levels at 100 and 200 ppm had harmful effectsand could be alleviated by the bio-fertilizers. Adding zinc levels at50 ppm increased the accumulation of nitrogen, magnesium, manganese,carbohydrates content, and total soluble protein in wheatshoots. Lower levels of zinc positively affected photosynthesis, indoleacetic acid and dry matter gain. Adding 25 ppm zinc in presence of biofertilizersenhanced phosphorus content in shoots while potassium andzinc uptake was inversely proportional with all sprayed zinc levels.