Effects of cyanobacterial suspensions as bio-fertilizers on growth factors and the essential oil composition of chamomile, Matricaria chamomilla L.

The cyanobacterial species used in this study were collected from medicinal plant beds and were cultured using nitrate free BG-11 medium. As heterocystous cyanobacteria fix atmospheric nitrogen and some of them additionally produce phytohormones, we hypothesized that using a suspension of beneficial cyanobacterial species in the soil of the plant might enhance its growth and would probably also affect the essential oil of this plant. Based on a seedling growth test, the cyanobacterial species Nostoc carneum, Wollea vaginicola and Nostoc punctiforme were selected for a pot trial. A glasshouse experiment with seven replicates was designed to evaluate the effects of the cyanobacterial suspensions on Matricaria chamomilla L. growth and essential oil production. The cyanobacterial suspensions were applied 15 days after planting. Fifty days after flowering the plants were harvested and the plant growth parameters were measured. Additionally, the chemical composition of soil samples from both the treatments and control pots were analyzed. All of the studied cyanobacterial suspensions had a significant effect on the weight of essential oil as well as on root growth. The chamazulene content of the essential oil in plants treated with N. carneum was 26.9% more than in the control. HPLC analysis revealed that the cyanobacterial species used in this experiment were able to produce plant growth-promoting hormones such as indole 3-acetic acid, indole 3-propionic acid and indole 3-butyric acid. There was a significant positive correlation between cyanobacterial IAA and all of the growth factors, as well as some constituents of the essential oil.