Hello everyone, and welcome back! I was just yesterday, chatting with a friend of mine about a paper I’m reading for a class. It concerned the relationship between plants and microbes…and then I dropped a word into the conversation…rhizosphere. What is that exactly? Where are the microbes? And what other factors affect plants?? I answered all these questions, and I also choose to explain them here this week.
Of course, when you look at a plant, there is the part you see above ground…but there is also a whole other world underground! The rhizosphere itself is a very small and specific area of soil surrounding the roots of plants. It is here that the plant roots release specific compounds to the soil, such as sugars, chemicals and other organic compounds. It is in the rhizosphere that you can find many microbes. The microbes can take up nutrients released from the plants, but then microbes can also help the plants by influencing the way they grow, for example. In some cases, such as with legumes, microbes can make nitrogen into a form that the plants can use. Plants and microbes can therefore form a symbiotic relationship. If you are a student, can you think of one type of microbe that lives in a symbiotic relationship with a type of plant?
There can also be plant-plant relationships, in addition to plant-microbe ones. Some plants are quite competitive, and so some of them release chemicals in the rhizosphere (or beyond), that can control the growth of other plants around them.
In addition to these many interactions happening in the rhizosphere (seems like a big party is happening over there!), resources that are essentially of the environment, such as temperature, water and sunlight, affect plants. These kinds of resources are called abiotic factors. Abiotic meaning not of, or from, a living thing. Biotic factors, on the other hand, include bacteria, plants, fungi and other living organisms, that are living components of ecosystems, and affect other parts of ecosystems, communities or even individuals of specific species.
Of course, there is so much ongoing research concerning these sorts of interactions, but much more needs to be known when it comes to the relationships of plants and microbes.
Take care until next time! 😊
Follow the links to read more on the rhizosphere, and abiotic vs biotic factors. Credit is given for use of images of plant root and rhizosphere, plants and roots in soil, and nitrogen fixing bacteria.
jtbtrinbagomicrobiologist 