The Importance of Photosynthetic Bacteria
EM is a multi-species, multi strain blend of beneficial naturally-occurring organisms that can be applied as inoculants to increase the microbial diversity of soil ecosystem. The inoculant is widely reported to consist mainly of the photosynthesizing bacteria, lactic acid bacteria, yeasts, actinomycetes and fermenting fungi but it is not limited to these microbes. These microorganisms are physiologically compatible with one another and can coexist in liquid culture. The real benefits however are in the impact each of these remarkable microbes has on the soil and on each other. In this blog series we are going to breakdown each group looking at the function of these unique microbes.
One of the major groups of Beneficial’s in EM includes a unique group of photosynthesising bacteria often referred to as Photosynthetic bacteria or Purple Non-Sulfur Bacteria (PNSB). These organisms can operate on the phyllosphere (leaf surface) and the rhizosphere (area around the roots). In the soil, these organisms have been shown to boost the metabolic activity of other beneficial bacteria, while stimulating root growth. On the leaf surface, they excrete phytohormones and enhance the activity of multiple phyllosphere species.
They are self-supporting organisms that produce sugars to stimulate other soil life. They can also build amino acids for the benefit of plants and other organisms. When EM is applied to soil or plant leaf surfaces, the populations of photosynthetic bacteria and nitrogen fixing bacteria increase dramatically. The phenomenon is associated with the growth of more vigorous plants, higher plant yields and improved crop quality compared with a non treated control. It was thought that the high number of photosynthetic bacteria and nitrogen fixing bacteria in soil and at leaf surfaces might enhance the plants photosynthetic rate and efficiency, and its nitrogen fixing capacity and in addition generate antioxidants, co-factors (substances that stimulate other organisms) and plant secondary metabolites to promote plant growth.
A recent Chinese study involving PNSB fertigated and foliar sprayed on stevia plants showed substantial results. Chlorophyll density increased, sugar levels increased, biological activity on the leaf and in the soil was enhanced and the yield of stevioside (a popular natural sugar alternative) increased by an impressive 61%.
This trial was showing the response of PNSB in isolation. Prof. Dr Higa, the creator of EM, has often stated that the sum of the combined micro-organisms are much greater than when in isolation. The PNSB in EM is a pivotal species to the success of EM.