Q.2 Which among the following organism(s) can be termed as bio fertilizers?
1. Azotobacter 2. Azolla
3. Blue green algae 4. Mycorrhizal
Select the correct answer using the codes given below:
a) 1, 2 and 4 only
b) 2, 3 and 4 only
c) 1, 2 and 3 only
Following are some of the important types of bio fertilizers which can be considered for agro based industries.
• Rhizobium biofertilizer: Rhizobium is a symbiotic bacteria forming root nodules in legume plants. These nodules act as miniature nitrogen production factories in the fields. The nodule bacteria fix more nitrogen (N2) than needed by legume plant and the bacteria. The surplus fixed nitrogen is then secreted and fertilizes the soil. Rhizobium is more efficient than-free living nitrogen-fixing bacteria and can fix upto 200 kg N/ha/yr.
• Azotobacter biofertilizer: Azobacter are aerobic free living nitrogen fixers. They grow in the rhizosphere (around the roots) and fix atmospheric nitrogen non symbiotically and make it available to the particular cereals. These bacteria produce growth promoting hormones which helps in enhancing growth and yield of the plant.
• Azospirillium biofertilizer: These are aerobic free living nitrogen fixers which live in associative symbiosis. In this type of association bacteria live on the root surface of the host plant and do not form any nodule with roots of grasses. It increases crop yield and its inoculation benefits crop. They also benefit the host plants by supplying growth hormones and vitamins. These bacteria are commonly used for the preparation of commercial inoculants.
• Blue green algae: Blue green algae (BGA or cyanobacteria) like Nostoc and Anabaena are free living photosynthetic organisms also capable of fixing atmospheric nitrogen. In the flooded rice fields blue green algae serves as a nitrogen biofertilizer.
• Azolla bio fertilizers: Azolla is a water fern inside which grows the nitrogen fixing blue green algae Anabaena. It contains 2-3% nitrogen when wet and also produces organic matter in the soil. The Azolla-Anabaena combination type biofertilizer is used all over the world. This can be grown in a cooler regions. But there is a need to develop a strain that can tolerant to high temperature, salinity and resistant to pests and diseases. Production technology is very easy and can be adopted by rice farmers. The only constraint in Azolla is that it is an aquatic plant and water becomes limiting factor in growing it particularly in summer.
• Phosphorus solubilising biofertilizer: Phosphorus is an important element required for plant growth. This element is also needed for nodulation by rhizobium. Some microorganisms are capable of solubilizing immobilized phosphorus making it available to plants for absorption.
• Mycorrhizal fungi acts as biofertilizer are known to occur naturally on roots of forest trees and crop plants. In soils low in available nutrients there is an increased absorption of nutrients by plants infected with Mycorrhiza. The fungus has the ability to dissolve and absorb phosphorus that plant roots cannot readily absorb
Q.3 Which among the following pairs is/are incorrectly matched?
1. Amylase: Breakdown starch
2. Pepsin: Breaking down of emulsified fats
3. Lipase: Digest Protein
Select the correct answer using the codes given below:
a) 1 and 2 only
b) 2 and 3 only
c) 1 and 3 only
Lipase is responsible for absorbing fat and is secreted in intestine of the human body.
b) Electromagnetic induction
2. Oil Shale gas is a mixture of propane and butane only.
Which of the statements given above is/are correct?
a) 1 only
b) 2 only
c) Both 1 and 2
Shale is a form of soft finely stratified sedimentary rock that formed from consolidated mud or clay and can be split easily into fragile plates.
There is no exact formula of oil shale gas. Compositions of oil shale gas depends on retorted oil shale and exploited technology. Typical components of oil shale gas are usually methane, hydrogen, carbon monoxide, carbon dioxide, nitrogen, and different hydrocarbons like ethylene. It may also consist of hydrogen sulfide and other impurities.
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