Rhizosphere Interactions Lab Report

1

Rhizosphere Interactions

Jacob Griganavicius

Robyn Dumalo

Introduction

Plants are the most important living organism on our planet today, without them; humans would most likely not be present on this planet. Plants are photoautotroph, which means they get energy from sunlight in order to change carbon dioxide (CO2) and water (H2O) into organic materials for all living organisms1

. The reason that plants are so important to humans is that they go through a main process to produce oxygen so humans can breathe and it is called photosynthesis. Photosynthesis is the process that converts light energy to chemical energy that is kept in sugars and any other organic compounds1

. Photosynthesis can occur anywhere there is green on the plant

There are two specific cycles that enable plants to get their nutrients from the soil; they are the cation exchange and the nitrogen cycle.

The first cycle that permits plants to get nutrients from the soil is the cation exchange.

The cation exchange is a process where cations are removed from the particles within the soil by other cations1

. In this process the replacement cations are usually removed by the cation H+

, a 2 hydrogen ion. For this process to be successful the plant must be able to know how much soil competence it has and it does that by establishing the number of cation adhesion sites and the pH levels within its soil2

. There are four crucial stages that plants go through when using the cation exchange to get nutrients from their soil. The first stage to this process is the plant’s roots are able to add acidification to its soil. The way that the plants soil is able to become more acidic is by releasing carbon dioxide from its own respiration and pumping hydrogen ions, H+ into the plants soil2

. The second part to this process is to allow carbon dioxide (CO2) and water

The final stage is for the roots to absorb all the cations that have been released from the bonding of the hydrogen ions and the negatively charged soil2

. These are the stages required for the plants to get nutrients from the soil by the cation exchange.

The next cycle that can be very valuable in plants being able to get nutrients within their soil is the nitrogen cycle. The nitrogen cycle is when nitrogen from the atmosphere or from decomposed organic material can be converted into nutrients by nitrogen-fixing bacteria1

. This process can be very successful for both the plants and the bacteria because they both end up giving each other something in return. The first step to this process works by the nitrogen-fixing bacteria being able to change the nitrogen gas (N2) into ammonia (NH3), then the ammonia

(NH3) can pick up a hydrogen ion (H+

) in the soil to become ammonium (NH4)

3

. After ammonium (NH4) is created, it is attacked by nitrifying bacteria because the plants like to get their nitrogen from nitrate (NO3

-

), so the nitrifying bacteria are able to turn ammonium (NH4) into the molecule nitrate (NO3