81. Name the scientific name of the microorganism that serves as an important biofertilizer in the
80. Use of biofertilisers in agriculture ensures a better environment. Justify. (A)
82. Give an example for a fungus which forms mycorrhiza. (K)
83. Name the bacterium found in the root nodule of leguminous plants. (K)
84. Write the function of Rhizobium in roots of leguminous plants. (K)
86. Mention the role of Azospirilum as biofertilizer. (K)
85. Give an example for free living bacterium which fixes atmospheric nitrogen. (K)
Answers
Answer:
81. Rhizobium is a symbiotic microorganism which serves as a biofertilizer.
80. A biofertilizer (also bio-fertilizer) is a substance which contains living micro-organisms which, when applied to seeds, plant surfaces, or soil, colonize the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant. Biofertilizers add nutrients through the natural processes of nitrogen fixation, solubilizing phosphorus, and stimulating plant growth through the synthesis of growth-promoting substances. The microorganisms in biofertilizers restore the soil's natural nutrient cycle and build soil organic matter. Through the use of biofertilizers, healthy plants can be grown, while enhancing the sustainability and the health of the soil. Biofertilizers can be expected to reduce the use of synthetic fertilizers and pesticides, but they are not yet able to replace their use. Since they play several roles, a preferred scientific term for such beneficial bacteria is "plant-growth promoting rhizobacteria" (PGPR).
82. Ectomycorrhizal fungi are mainly Basidiomycota and include common woodland mushrooms, such as Amanita spp., Boletus spp. and Tricholoma spp. Ectomycorrhizas can be highly specific (for example Boletus elegans with larch) and non-specific (for example Amanita muscaria with 20 or more tree species).
83. Rhizobium is a genus of bacteria associated with the formation of root nodules on plants. These bacteria live in symbiosis with legumes. They take in nitrogen from the atmosphere and pass it on to the plant, allowing it to grow in soil low in nitrogen
84. Rhizobia are a "group of soil bacteria that infect the roots of legumes to form root nodules".Rhizobia are found in the soil and after infection, produce nodules in the legume where they fix nitrogen gas (N2) from the atmosphere turning it into a more readily useful form of nitrogen. From here, the nitrogen is exported from the nodules and used for growth in the legume. Once the legume dies, the nodule breaks down and releases the rhizobia back into the soil where they can live individually or reinfect a new legume host.
85. Nitrogen Fixation by Free-Living Heterotrophs
Examples of this type of nitrogen-fixing bacteria include species of Azotobacter, Bacillus, Clostridium, and Klebsiella.
86. Bio fertilizer azosipirillium a free-living nitrogen-fixing bacteria closely associated with grasses. ... Azospirillum biofertilizer also secretes some fungicides, enzymes but in minute amount. Use of Azospirillum biofertilizer increases the crop production in large scale.
Answer:
ans./Rhizobium
Explanation:
Rhizobium is a symbiotic microorganism which serves as a biofertilizer. It lives in symbiotic association with leguminous plants. It makes available the atmospheric nitrogen to the plant.