Enhancement of essential oil composition in medicinal plants by cyanobacterial treatment

Although nitrogen fixation is the mo st important feature of cyanobacteria but prod uction of biologically active compounds and their impact on plants growth is also important. Use of cyanobacteria as a biofertilizes on d ifferent plants is not a new case. There are numerous reports regarding significant enhance ment of plants growth by cyanobacteria. However this study for the first time illustrated the positive effect of cyanobacteria on medicinal p lants. An enhancement of essential oil compo sition was achieved in Matricaria chamomilla L. and different species of Mentha treatment with cyanobacteria. Although nitrogen fixation by blue-green algae may often be an important factor in maintaining soil fertility, the algae may directly or indirectly benefit higher plants in other ways. The algae can bind soil particles togeth er, due to the adhesive properties of the copious mucilage excreted by many algal species. Thus they may reduce soil erosion and also evaporati ve water loss from soils 9 as desiccated algal crusts form a relatively impermeable cover over the soil surface. Some reports indicate that blue-gre en algae may release biologically active compo unds into the soil and that these compounds ma y then be assimilated by higher plants, significantly enhancing their growth 6 13,16. At present few data are available concerning this aspect of blue-green algal physiology.