What Is a Rhizoid?

Root nodule is a special tumor that grows on the roots of plants. It is formed by the formation of symbiotic nitrogen-fixing bacteria in parasitic tissues. It is used to synthesize its own nitrogen-containing compounds (such as proteins), and some cultural circles prefer root nodules.

Some microorganisms in the soil can enter the root tissue and symbiotic with the root. There are two types of symbiosis, namely root nodule and mycorrhizal. Nodules are caused by beneficial bacteria that invade root tissues. This kind of bacteria is called rhizobium. Rhizobium multiplies in the root cortex, stimulates cortical cell division, and causes the root tissue to expand and protrude to form nodules. Rhizobia can convert free nitrogen in the air into nitrogenous compounds that can be used by plants. This is called nitrogen fixation. Legumes, flowers and some green manure plants and lawn grasses in horticultural plants have nodules. Nitrogen-fixing plants can reduce the use of nitrogen fertilizer, increase soil organic matter, and improve soil physical properties. Some woody plants such as Myrica, Alnus, Elaeagnus, and Casuarina also have root nodules. ^[1]

Rhizobium rapidly divides and reproduces in cortical cells. At the same time, cortical cells also rapidly divide and grow due to the stimulation of nodule invasion, which causes the local volume of the root to expand and form nodules, which is the nodules. Rhizobia take in the water and nutrients they need from their nodules. They can fix free nitrogen and synthesize nitrogenous compounds, which are used by legumes. The symbiosis of leguminous plants and rhizobium is highly yielded by obtaining nitrogen; at the same time, due to the shedding of nodules, roots or residual plants with nodules are left in the soil, which can increase soil fertility. Use legumes for green manure or other crops

The nodule formation process is roughly like this:

After a large number of cultures, rhizobium is mixed with an appropriate amount of adsorbent (such as peat, etc.). It is mainly inoculated on the seeds of leguminous crops and infects the roots to form nodules. Nodules can fix nitrogen in the atmosphere to nitrogen compounds that can be directly used by crops through the action of nitrogenase. Rhizobia are the microorganisms with the highest nitrogen fixation rate in biological nitrogen fixation.

Rhizobia is a kind of biological fertilizer widely used in China. Due to the strong specificity of rhizobium, one kind of rhizobium can only be applied to one (class) crop. So far there is no rhizobium suitable for various crops, so there are many types of rhizobium. Commonly used are soybean rhizobium agents (divided into fast-growing and slow-growing types), peanut rhizobium agents, leguminous and forage rhizobium agents (broomcorns, ascot, barberry, red sage, red clover, White clover, stylosanthes, leucaena, big wing beans, vegetative roots, big red beans, chain beans and locusts, etc.).
Different strains of rhizobium are produced in different places, so the nitrogen fixation rate and yield increase effect are very different. In order to improve the nitrogen fixation rate of rhizobium agents, strains with strong resistance to stress should be selected according to local soil and climatic conditions.
The rhizobium used in agricultural production mainly uses the liquid deep culture-peat adsorption process. In addition, there is a lyophilized rhizobium agent, which has the advantages of high bacteria content, small volume, and convenient transportation and storage.

Rhizobia are mainly used for seed dressing. The method is as follows: first, the fungicide (1.5 to 3.75 kg / ha, that is, 250 to 500 g / mu) is mixed with water (3.75 to 7.50 kg / ha, that is, 250 to 500 g / mu) into a paste, and the test crop Stir in the seeds, mix well, immediately sow and cover the soil. During seed dressing and sowing, do not contact with pesticides or expose to the sun. In order for Rhizobium to infect crops more quickly in the soil, they must be provided with sufficient phosphorus and a suitable pH. The test proves that when the soil pH is 5.2, the applied rhizobium will die 65%; if the soil pH is less than 4.5, the rhizobium will be difficult to survive in the soil. Therefore, for acid soils, after mixing the crop seeds and rhizobium agents, they are then mixed with mud, calcium magnesium phosphate fertilizer, or lime and other materials to form a "pill coat". This helps the rhizobium to survive in the soil, easily infects crops, and nodules and early nodules to improve the rate of nitrogen fixation.
Rhizobium on the soil where legumes have never been planted has a significant yield-increasing effect. However, on the soil of the same race of legumes, the inoculation amount of rhizobium must be increased, otherwise the effect is not obvious or ineffective.
In addition, if legume crops are not seeded with rhizobia in time when sowing, the rhizobium can be adjusted to a suspension and applied near the roots of the crop, so that leguminous crops can form nodules. Otherwise the effect is not good.
In order to improve the nitrogen-fixing effect of rhizobium agents, a new type of rhizobium agent, a rare earth bacteria agent, has been produced. This rhizobium agent containing 0.1% rare earth compound can enhance the survival rate of rhizobium and its ability to infect and nodulate host crops, and its yield increase effect is higher than that of ordinary rhizobium agents.

Plants with rhizobium-Ziyunying (5 photos)