Quantitative and Qualitative Evaluation of Auxin (IAA) Production Potential of Cyanobacteria, Isolated from Guilan Paddy Fields

Cyanobacteria represent a less investigated group of prokaryotes, in terms of their effect on plant growth, especially in relation with the production of phytohormones. The present research was aimed at evaluating Indole Acetic Acid (IAA) production potential of cyanobacteria strains isolated from Guilan paddy fields through the two quantitative and qualitative methods, their potential being determined in terms of rice seed germination indices. The results obtained indicated that some cyanobacteria isolates could produce auxin hormone IAA.GGuCy-34 and GGuCy-42 isolates respectively produced 14.98 and 10.83 [µg IAA/(ml. Chl. a)] in no L-Trp treatment, GGuCy-34, GGuCy-15 and GGuCy-42 isolates respectively produced 23.7, 17.46 and 15.81 [µg IAA/(ml. Chl. a)] in 100 (mg L-Trp/ml) treatment and GGuCy-15 and GGuCy-16 isolates respectively produced 29.16 and 21.61 [µg IAA/(ml. Chl. a)] in 500 (mg L-Trp/ml) treatment. The results finally revealed that IAA production is highly correlated with the type of isolate and as well with the culture medium. Germination energy and germination rates increased in the cases of GGuCy-25, GGuCy-42, GGuCy-41, GGuCy-26 and GGuCy-50 isolates, and while dry radical weight as well as dry plumule weight increased in the cases of GGuCy-42, GGuCy-50, GGuCy-25 isolates.