Question

Which one of the following helps in the absorption of phosphorus from the soil by the plants?
A. Anabaena
B. Glomus
C. Rhizobium
D. Frankia

Answer 1

As nutrients are mostly depleted in the soil, therefore most of the plants form a type of symbiotic relationship with certain types of fungi, and this relationship is called as mycorrhizae. The relationship between plants and fungi are symbiotic because the plant obtains essential elements and other minerals from fungus, and in return fungus absorbs certain sugars from the plant root.

Complete answer:
Phosphorus is an essential part or component of the nucleic acid of the DNA and ATP (i.e. basic units of energy) in the structure of plants. It also plays a major role in the protein synthesis, growth, general health and vigour of plants cells and tissues.

Glomus comes under arbuscular mycorrhizal fungi that are mainly responsible for the absorption of various nutrients such as phosphorus. Also, other benefits to plant hosts include improved nutrient uptake, drought resistance, and disease resistance. Glomus forms endo-mycorrhizae with the root of plants and helps in the abruption of phosphorus and nutrition for plants.

Rhizobium is a type of bacteria that is found in soil and plays an important role in fixing nitrogen in leguminous plants. It gets attach by the roots of the leguminous plant and forms nodules. These nodules are the real site where atmospheric nitrogen get fix and conversion into ammonia happens that is used by the plant for its growth and development.

Anabaena falls under the category of genus of filamentous cyanobacteria that exist as plankton. They generally have nitrogen-fixing qualities, and they are to maintain symbiotic relationships with certain plants, for example, the mosquito fern.

Frankia are categorized as Gram-positive and Gram-variable actinomycetes that exit in hyphal form in growth. As the cyanobacteria fixes nitrogen in plants, in the same way almost all frankia strains are capable of fixing nitrogen in the free-living state.

Hence, the correct answer is option (B).

Note: The glomus mycorrhiza, the plant supplies the fungus with carbon, while the fungus increases the ability of the plant to uptake nutrients (mainly phosphorus).
Two types of nitrogen-fixing bacteria exist. In the first types, the free-living (nonsymbiotic) bacteria includes the cyanobacteria also called as blue-green algae, anabaena and nostoc. The type is mutualistic (symbiotic) bacteria (Rhizobium).