Evaluation and characterization of the plant growth promoting potentials of two heterocystous cyanobacteria for improving food grains growth.

Abstract Cyanobacteria are potential prokaryotes found in diverse environment of freshwater and marine water ecosystem. They are well known applicant practised in ancient agriculture technique for improving the soil fertility, water holding capacity and texture of the soil. The availability, low cost and fast growth has considered them as superior candidate for biotechnological applications. In the recent years, cyanobacteria are been used to produce plant growth promoting hormones or substances for facilitating effective plant growth. The present study is focussed on validating the plant growth promoting ability of two heterocystous cyanobacteria strains (Anabaena variabilis , Nostoc calcicola) in five crop plant. The cyanobacterial strains were characterized by biochemical and plant growth promoting parameters like Chlorophyll content and IAA production. As result of this study, in vitro experiments revealed 100% of seed germination by Cyanobacteria growth promoting substances (CGPS) of Anabaena variabilis in the grains of Zea mays and Sorghum bicolour , while 90% germination in Nostoc calcicola. Statistical analysis proved the growth root length, plant height, weight of fresh and dry root, number of leaves in CGPS treated and untreated plant in pot. Further the CGPS was characterized using thin-layer chromatography (TLC), FT-IR and HPLC analysis. The dominant auxins in the two isolates were IAA in the range of 0.0372–1.2327 μg g⁻¹ dry weight was detected. However, IAA production by Anabaena variabilis proved as potential candidate for promoting plant growth. In addition, Anabaena variabilis can also be utilized as a biofertilizer for the crops cultivated in normal fields. Highlights • Cyanobacteria are efficient plant growth promoting sources to help growth of food crops. • Cyanobacterial intracellular products contains large number of enzymes and growth promoting hormones. • Use of heterocystous cyanobacterial biomass as fertilizer will provide multiple benefits to plant and soil. [ABSTRACT FROM AUTHOR]