PGPR is a type of bacteria that live around the plant roots. The bacteria colonize his life enveloped plant roots. For plants where microorganisms will be very good. These bacteria provide benefits in the process of plant physiology and plant growth boosters growth Rhizobakteria (RPTT) is a group of beneficial bacteria that aggressive occupying (colonize) rhizosphere (root section). RPTT activities beneficial to the plants, either directly or indirectly. RPTT direct influence based on its ability to provide and mobilize or facilitate the absorption of various nutrients in the soil as well as synthesize and transform fithothormon concentration hyper growth. While indirect related to the ability of suppressing the activity of a pathogen by producing a variety of compounds or metabolites such as nutrient providers antibiotik. a number of bacteria living in root rhizosphere (rhizobacteria) called rhizobacteria boosters grow plants (plant growth promoting rhizobacteria = PGPR). This group has a dual role in the side (1) anchored N2, too; (2) produce growth hormones (such as IAA, gibberellins, cytokinins, ethylene, and others); (3) suppress plant diseases soil origin with glucanase, chitinase, cyanide produce siderophores; and (4) dissolving the P and other nutrients (Cattelan et al., 1999; Glick et al., 1995; Plant growth-promoting rhizobacteria (PGPR) was first investigated by Kloepper and Scroth (1982) to describe a soil bacteria that inhabit the root zone the plants are inoculated into the seed and could increase plant growth. Since it was first introduced by Kloepper and Scroth (1982), PGPR has developed very quickly, especially in the last few years. PGPR is Around the Root, root is the source of life, there occurs an exchange air, nutrients, decomposition etc. The function of PGPR for the plant that is able to stimulate the growth and physiology of root and capable of reducing disease or damage by insects. Another function is in addition to compost and accelerate the composting process. Reduction of pesticides and crop rotation can spur the growth of the population of bacteria - beneficial bacteria such as PGPR.
Applications PGPR is able to reduce the incidence and severity of disease. Some PGPR inoculated bacteria on the seeds before planting can give the defense on the hood of the roots of plants. This makes PGPR bacteria capable of reducing the severity of disease dumping-off (Pythium ultimatum) in the plant. Some PGPR bacteria capable of producing toxic to plant pathogens, such as bacteria Bacillus subtilis capable against fungal pathogens.
PGPR can improve plant growth through: the production of growth hormone N fixation ability to increase soil N supply, producing osmolit as osmoprotektan in drought stress conditions and producing specific compounds that can kill plant pathogens (Kloepper, 1993).
According to Lalande et al. (1989), Pseudomonas sp. able to produce plant growth hormone boosters can increase the dry weight of corn plants reach 9%, while Salmonella liquefaciens increase dry weight reached 10% and Bacillus sp. improve dry weight reaches 7% higher than controls.
Here are the advantages of PGPR include:
- Increase of nitrogen fixation in pea crops - beans
- Stimulating the growth of bacterial nitrogen fixation free
- Increasing the availability of other nutrients like phosphate, sulfur, iron and copper
- Producing plant hormones
- Adding beneficial bacteria and fungi
- Controlling pests and plant diseases
Similarly, a review of what the PGPR may be useful for farmers, and to learn about how to make PGPR can be read also "how to make PGPR".