The Effects of Probiotics on Plants and Crops Health and Growth

There are many types of microorganisms which are used in the production of biofertilizer. Biofertilizers could be made from beneficial bacteria, microorganisms, fungi or algae. They are not commercially made using vast amounts of non-renewable energy like all fertilisers and are low-cost in the production. Since the microorganisms are living they can associate themselves very well with plant roots. We thought about different living microorganisms in our own bodies and the microorganism that pops into everyone’s head is: probiotics. In fact, probiotics carry two pounds of our total body weight. They are found in the stomach lining, in the gut and in the intestinal tract. They are very beneficial to the human body and here are only some of the things they do to us:

a) Enhance immune function

b) Help with the side effects of antibiotic therapy

c) Helps digestive system function

d) Decrease the risk of certain cancers

But would they be as beneficial to plants as they are to humans? They are living microorganisms after all. Is it possible to classify probiotics as a biofertilizer? It’s time to find out. Here are common questions asked about the effects probiotics have on plants as follows:

1. If probiotics are applied to seed, do they increase the percentage of germination?
2. If probiotics are applied to seed, do they develop a strong, secondary root system?
3. If probiotics are applied to seed, do they promote a healthy shoot structure?

We will be testing our experiment on water, Mycorrhizal Fungus and probiotics. After research and some advice from our local health shop, we chose what strain of probiotic to use in our experiment. We decided on lactobacillus sporogenes a strain not very well known in the scientific community. In our experiment, we immersed three groups of seed (radish and pea) in either probiotic solution, Mycorrhizal Fungus solution or water for ten minutes. We then placed each group of seeds on dampened tissue paper and then left for 6 days and recorded what happened each day.

In our experiment we are going to use probiotics as this is what we want to investigate, Mycorrhizal Fungus an already known biofertilizer and water to see what the plants would be like if we applied nothing to them.

A biofertilizer is a substance which contains living microorganisms which, when applied to seed, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant. Since microorganisms are almost living they symbiotically associate themselves with plant roots. Root colonizing bacteria are known to produce growth hormones which often lead to increased root growth and structure (Hazarika and Ansari, 2007).

They also help plants to resist diseases. Nitrogen fixing bacteria and phosphate solubilizer are the main biofertilizers for horticultural crops. There are many experiments that try to see if a certain type of microorganism will affect plant growth. One such experiment is called: Influence of Effective Microorganisms on Seed Germination and Plantlet Vigor of Selected Crops. Here, they immerse the seed in Effective Microorganisms for ten minutes and measure the roots. This is where we got the idea for immersing the seeds. Here are some of the influences biofertilizers have:

Effect of biofertilizers on crop yield: Azospirillum (biofertilizer) + 150kg N/ha can increase the yield in strawberry 54% more, than with the N/ha alone (Wang, 1996). It has been said by Chezhiyan in 1999 that with application of a biofertilizer, they got 15.3kg more bananas than without.

Effect of biofertilizers on soil character: Wani, 1990 has said that plants inoculated with Azospirillum have increased nitrate reductase activity in plants and production of antifungal compounds.

Based on data from the experiment, it appears that probiotics protect the plant from bad bacteria and it also plays a part in getting the seed to bring out its shoots as we have seen in the second experiment. The Mycorrhizal Fungus has indeed developed a complex, strong root system for the plant as was expected. With the answers and data we collected, we can now restate the hypothesis and give an answer to our two questions

1. Lactobacillus sporogenes (strain of probiotic) does protect the plant and enhances immune function however it does not promote a healthy shoot structure neither does it develop a complex, secondary root system. The germination of seeds which were immersed in probiotic solution began germinating 4 days after immersion which in comparison with the fungus is very late. Probiotics make almost all the seeds to come out as shoots and healthy ones too.
2. Mycorrhizal Fungus does develop a complex, strong, secondary root system and it does promote a healthy shoot structure only after a week of planting. When seedlings are first planted the seedlings, they are very weak and wilted indeed which shows that all the nutrients and energy the seedling gets is was going to the roots. However, after a certain period of time, when the roots are firmly established, the seedlings then distribute the nutrients and energy evenly throughout the plant. There is a certainty that if anything attacks the plant, regardless even if it has good roots the plant will die.

Our conclusions show that neither the probiotics nor the Mycorrhizal Fungus can do everything listed below.

a) Immunise and protect the plant from harmful bacteria

b) Develop a strong, secondary root system

c) Germinate almost 100% of seeds

d) Promote a healthy shoot structure

But by using our data and results, we are going to create a solution of both Mycorrhizal Fungus and Lactobacillus Sporogenes so the results of the fungus and the results of the probiotics will be mixed together and we can do all of the things above in one immersion. It will be a difficult task because we will need to find the correct ratio of fungus to probiotics. We are thinking of having more fungus than probiotics in our solution because we mainly need the fungal more than the probiotic.

There may have been possible sources of error in the experiments which could have been the following:

• When examining the radish seeds as they were small, we might have not seen imperfections on one or two of the seeds and they mightn’t have germinated because they were bad seeds. This could have affected the percentage of seeds that germinated.
• We might have made a weak probiotic solution and that is why it did not work as well as expected.

If these solutions were used in Third World Countries, they would be able to yield better harvests and give immunisation to the plants. Also their plants will have more support from the strong and powerful root system. More of the seeds would germinate too.

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