Tag: manure

Microorganisms which, when applied to seed, plant surfaces, or soil, colonizes the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant. Rhizobium can be used as biofertilizer. Rhizobium 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 usable form of nitrogen.

Mycorrhizal fungi, which form a symbiosis with the roots of nearly all vascular plants, play a key role in solving the phosphate shortage problem for plants. Mycorrhizal fungi can effectively increase phosphate uptake by converting insoluble phosphates to soluble, available forms.

Leg-haemoglobin is an oxygen carrier. It is found in root nodules of leguminous plants. It is red in colour and is a hemoprotein. It provides or helps in providing oxygen to symbiotic bacterial cells. 

Leghaemoglobin helps to mantain internal oxygen in symbiotic nodules, because this protein has ten times more affinity for oxygen as compared to blood pigment haemoglobin.Therefore they acts as oxygen scavenger.

Rhizobium is microaerophilic rod shaped gram negative bacteria found in association with legume plants in root nodules. These bacteria fix atmospheric nitrogen into ammonium ions, which can be readily assimilated by plants.

Plants cannot consume atmospheric nitrogen directly, because in atmosphere nitrogen occurs in stable diatomic form. The atmospheric nitrogen needs to be converted into plant usable forms like nitrate, nitrite and ammonium ion. This process is called as nitrogen fixation. 

Nodules develop in the roots of leguminuos plants like pulses and grams. These nodules have a very specific function. They inhabit rhizobium bacteria. it is a type of nitrogen fixing bacteria, It absorbs free nitrogen from the atmosphere and converts it into nitrites and nitrates and fixes it in the soil. From soil, plants absorb nitrogen fixed by the bacteria. So, nitrogen requirement of leuminuous plants is fulfilled.

In the roots of legumes, there live many bacteria, who through their own metabolic processes are able to convert the nitrogen gas into ammonia or ammonium, depending on the acidity of the soil. Converting nitrogen gas into a more usable form is extremely difficult and is the reason that this process is so specialized. While ammonium may be usable by a few plants, the majority cannot use it and another process is required. Nitrifying bacteria oxidize the ammonia creating nitrite then nitrate allowing for the nitrogen to be assimilated into the plants.

Many rhizobia, nitrogen fixing bacteria, live in a symbiotic relationship with plants known as legumes. In such plants, the presence of oxygen in the root nodules would reduce the activity of the oxygen-sensitive nitrogenase. In these situations, the roots of such plants produce a protein known as leghemoglobin. Leghemoglobin buffers the concentration of free oxygen in the cytoplasm of infected plant cells to ensure the proper function of root nodules. Leghemoglobin is a nitrogen or oxygen carrier; naturally occurring oxygen and nitrogen interact similarly with this protein. Hence option B is correct.