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What role do certain microorganisms in the root nodules of leguminous plants play?
  • a)
    They cause diseases
  • b)
    They fix nitrogen from the air into the soil
  • c)
    They decompose organic matter
  • d)
    They produce toxins
Correct answer is option 'B'. Can you explain this answer?
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What role do certain microorganisms in the root nodules of leguminous ...
Microorganisms residing in the root nodules of leguminous plants fix nitrogen from the air into the soil, enhancing soil fertility. This process is crucial for providing essential nutrients to plants.
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What role do certain microorganisms in the root nodules of leguminous ...
Role of Microorganisms in Root Nodules
Leguminous plants, such as peas, beans, and clover, form a symbiotic relationship with certain microorganisms, primarily rhizobia, within their root nodules. This interaction is crucial for nitrogen fixation, a vital process for soil fertility and plant growth.
What is Nitrogen Fixation?
- Nitrogen fixation is the conversion of atmospheric nitrogen (N2) into ammonia (NH3) or related compounds.
- This process is essential because most plants cannot utilize atmospheric nitrogen directly.
Function of Rhizobia
- Rhizobia are soil bacteria that infect the root hairs of leguminous plants.
- Upon infection, they stimulate the formation of root nodules, where they reside and multiply.
How Nitrogen Fixation Occurs
- Inside the root nodules, rhizobia convert nitrogen gas from the atmosphere into ammonia.
- This ammonia is then used by the plant to synthesize proteins and other essential compounds.
Benefits to the Ecosystem
- The fixed nitrogen enriches the soil, making it more fertile for subsequent crops.
- This process reduces the need for synthetic nitrogen fertilizers, promoting sustainable agriculture.
Conclusion
The microorganisms in the root nodules of leguminous plants play a critical role in fixing nitrogen from the air into the soil, benefiting both the plants and the broader ecosystem. This symbiotic relationship is a key aspect of nutrient cycling in agricultural systems.
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Directions for the following 7 (seven) items: Read the following two passages and answer the items that follow each passage. Your answers to these items should be based on the passages only.Passage -1The law in many parts of the world increasingly restricts the discharge of agricultural slurry into watercourses. The simplest and often the most economically sound practice returns the material to the land as semisolid manure or as sprayed slurry. This dilutes its concentration in the environment to what might have occurred III a more primitive and sustainable type of agriculture and converts pollutant into fertilizer. Soil microorganisms decompose the organic components of sewage and slurry and most of the mineral nutrients become available to be absorbed again by the vegetation.The excess input of nutrients, both nitrogen and phosphorus - based, from agricultural runoff (and human sewag e) has caused many healthy oligotrophic lakes (low nutrient concentrations, low plant productivity with abundant water weeds, and clear water) to change to eutrophic condition where high nutrient inputs lead to high phytoplankton productivity (sometimes dominated by bloomforming toxic species). This makes the water turbid, eliminates large plants and, in the worst situations, leads to anoxia and fish kills; so called cultural eutrophication. Thus, important ecosystem services are lost, including the provisioning service of wild-caught fish and the cultural services associated with recreation.The process of cultural eutrophication of lakes has been understood for some time. But only recently did scientists notice huge dead zones in the oceans near river outlets, particularly those draining large catchment areas such as the Mississippi in North America and the Yangtze in China. The nutrient-enriched water flows through streams, rivers and lakes, and eventually to the estuary and ocean where the ecological impact may be huge, killing virtually all invertebrates and fish in areas up to 70,000 km2 in extent. More than 150 sea areas worldwide are now regularly starved of oxygen as a result of decomposition of algal blooms, fuelled particularly by nitrogen from agricultural runoff of fertilizers and sewage from large cities. Oceanic dead zones are typically associated withindustrialized nations and usually lie off- countries that subsidize their agriculture, encouraging farmers to increase productivity and use more fertilizer.Q.According to the passage, why should the discharge of agricultural slurry into watercourses be restricted?1. Losing nutrients in this way is not a good practice economically.2. Watercourses do not contain the microorganisms that can decompose organic components of agricultural slurry.3. The discharge may lead to the eutrophication of water bodies.

Passage -1The law in many parts of the world increasingly restricts the discharge of agricultural slurry into watercourses. The simplest and often the most economically sound practice returns the material to the land as semisolid manure or as sprayed slurry. This dilutes its concentration in the environment to what might have occurred III a more primitive and sustainable type of agriculture and converts pollutant into fertilizer. Soil microorganisms decompose the organic components of sewage and slurry and most of the mineral nutrients become available to be absorbed again by the vegetation.The excess input of nutrients, both nitrogen and phosphorus - based, from agricultural runoff (and human sewag e) has caused many healthy oligotrophic lakes (low nutrient concentrations, low plant productivity with abundant water weeds, and clear water) to change to eutrophic condition where high nutrient inputs lead to high phytoplankton productivity (sometimes dominated by bloomforming toxic species). This makes the water turbid, eliminates large plants and, in the worst situations, leads to anoxia and fish kills; so called cultural eutrophication. Thus, important ecosystem services are lost, including the provisioning service of wild-caught fish and the cultural services associated with recreation.The process of cultural eutrophication of lakes has been understood for some time. But only recently did scientists notice huge dead zones in the oceans near river outlets, particularly those draining large catchment areas such as the Mississippi in North America and the Yangtze in China. The nutrient-enriched water flows through streams, rivers and lakes, and eventually to the estuary and ocean where the ecological impact may be huge, killing virtually all invertebrates and fish in areas up to 70,000 km2 in extent. More than 150 sea areas worldwide are now regularly starved of oxygen as a result of decomposition of algal blooms, fuelled particularly by nitrogen from agricultural runoff of fertilizers and sewage from large cities. Oceanic dead zones are typically associated withindustrialized nations and usually lie off- countries that subsidize their agriculture, encouraging farmers to increase productivity and use more fertilizer.Q.The passage refers to the conversion of pollutant to fertilizer. What is pollutant and what is fertilizer in this context?

Passage -1The law in many parts of the world increasingly restricts the discharge of agricultural slurry into watercourses. The simplest and often the most economically sound practice returns the material to the land as semisolid manure or as sprayed slurry. This dilutes its concentration in the environment to what might have occurred III a more primitive and sustainable type of agriculture and converts pollutant into fertilizer. Soil microorganisms decompose the organic components of sewage and slurry and most of the mineral nutrients become available to be absorbed again by the vegetation.The excess input of nutrients, both nitrogen and phosphorus - based, from agricultural runoff (and human sewag e) has caused many healthy oligotrophic lakes (low nutrient concentrations, low plant productivity with abundant water weeds, and clear water) to change to eutrophic condition where high nutrient inputs lead to high phytoplankton productivity (sometimes dominated by bloomforming toxic species). This makes the water turbid, eliminates large plants and, in the worst situations, leads to anoxia and fish kills; so called cultural eutrophication. Thus, important ecosystem services are lost, including the provisioning service of wild-caught fish and the cultural services associated with recreation.The process of cultural eutrophication of lakes has been understood for some time. But only recently did scientists notice huge dead zones in the oceans near river outlets, particularly those draining large catchment areas such as the Mississippi in North America and the Yangtze in China. The nutrient-enriched water flows through streams, rivers and lakes, and eventually to the estuary and ocean where the ecological impact may be huge, killing virtually all invertebrates and fish in areas up to 70,000 km2 in extent. More than 150 sea areas worldwide are now regularly starved of oxygen as a result of decomposition of algal blooms, fuelled particularly by nitrogen from agricultural runoff of fertilizers and sewage from large cities. Oceanic dead zones are typically associated withindustrialized nations and usually lie off- countries that subsidize their agriculture, encouraging farmers to increase productivity and use more fertilizer.Q.According to the passage, what are the effects of indiscriminate use of fertilizers?1. Addition of pollutants to the soil and water.2. Destruction decomposer of microorganisms in soil.3. Nutrient enrichment of water bodies.4. Creation of algal blooms.

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What role do certain microorganisms in the root nodules of leguminous plants play?a)They cause diseasesb)They fix nitrogen from the air into the soilc)They decompose organic matterd)They produce toxinsCorrect answer is option 'B'. Can you explain this answer?
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