Plants must have nitrates to help them grow. What must happen to nitrogen for it to be usable by plants
Nitrogen must be converted into nitrates by nitrogen-fixing bacteria in the soil or through industrial processes such as Haber-Bosch process to be usable by plants.
In order for nitrogen to be usable by plants, it must undergo a process called nitrogen fixation. Here are the steps involved:
Step 1: Nitrogen Fixation: Nitrogen gas (N2) from the atmosphere is converted into a usable form by nitrogen-fixing bacteria. These bacteria have the ability to convert atmospheric nitrogen into ammonia (NH3). Some plants, like legumes (e.g., soybeans, peas, clover), have a symbiotic relationship with nitrogen-fixing bacteria that live in their root nodules. The bacteria convert nitrogen gas into ammonia, which the plants can use as a nutrient.
Step 2: Nitrification: Ammonia, produced through nitrogen fixation or through decomposition of organic matter, is converted into nitrates (NO3-) through a process called nitrification. This process involves two steps carried out by different types of bacteria. Firstly, ammonia is oxidized into nitrite (NO2-) by nitrifying bacteria. Then, nitrite is further oxidized into nitrate by other nitrifying bacteria.
Step 3: Nitrate Uptake: Once nitrates are available in the soil, plants can absorb them through their root systems. The plant roots have specialized cells, such as root hairs, that increase the surface area for absorption. The nitrates are taken up by these cells through a process called active transport.
Step 4: Nitrogen Assimilation: Inside the plant, the nitrates are converted into various organic forms of nitrogen, such as amino acids and proteins, through a process called nitrogen assimilation. This allows the plant to use the nitrogen to produce new cells and grow.
Therefore, through nitrogen fixation, nitrification, nitrate uptake, and nitrogen assimilation, nitrogen is made usable by plants for their growth and development.