Coexistence between microorganisms and plants takes place in the root zone of plants, because in this area provided a number of compounds required by a microorganism for the life and activities. This compound is in the form of root exudates useful as a source of C, N and energy for microorganisms, ranging from a simple organic compounds up to complex organic compounds. Improving the living and the development of microorganisms as a result of root exudates known as the rhizosphere effect.
Generally, the type of microorganisms that inhabit the root zone is not different from the microorganisms living in the soil, it’s just that the population in the root zone is much higher. The roots of plants greatly affect the lives of the bacteria on their effects on fungi, particularly gram-negative bacteria. Bacteria gram positive bacteria show a decrease in the root zone. Effect of rooting against fungi is selective, meaning that the roots of plants only stimulates the fungus lives.
In the root zone, the density of the bacteria may fluctuate in line with changes in the surrounding environment. Changes that can occur because of the provision of land pembenah materials (eg, organic materials), application of foliar fertilizer, pesticide and seed bacterial inoculation on or directly in the soil microorganisms that thrive in the root zone has diverse nature of life that is non symbiotic and symbiotic.
The pattern of life for non-symbiotic microorganisms that might be a free or associated with plants. For example, some bacteria are classified as free-living include Azotobacter, Beijirinckia, Mycobacterium, Arthrobacter, Bacillus; Pseudomonas, Klebsiella, Clostridium, and Rhodospirillum. For this group of microorganisms, will utilize a wide variety of organic compounds (organic compounds ranging from simple to complex) as a source of carbon and energy.
Organic compounds in question include monosaccharides, disaccharides and polysaccharides, organic acids from fatty acids, aromatic organic acid, ethyl alcohol, glycerol, mannitol and organic acids volatile. By contrast, the microorganisms that live in association with plants. Association microorganisms in plants may also take place in endorhizosfer or ektorhizosfer. The development and activity of life is very dependent on the suitability of the plant.
This is because there are organic compounds specifications required by microbes as a source of C, N and energy. While the compound is only found in certain plant root exudates. An example, Azospirillum brasilensis will be encouraged development and activity when associated with a C4 plant, because the C4 plant exudates contained malic acid which is useful as a primary energy source.
Consider the following Figure 1:33. This image shows a wetland that is inundated or if the terms of the land with a porosity porosity is bad, because the land no longer has the soil pores. Thus soil conditions, if used for rice cultivation, it will not adversely affect the growth of the rice plant, because the rice plant is a type of plant that requires waterlogged conditions for growth.
But if the land will be used for the cultivation of corn, peppers or other crops, the soil does not have pores land is not suitable, even the plants will die, because waterlogged conditions. For the cultivation of crops is generally desired land with good porosity, which has enough pores of the soil macro and micro
Figure 1. Soil 37. Rice with recent Porosity