Question

The symbiotic association between fungi and roots of higher plants is referred to as:
A) Lichen
B) Mycorrhiza
C) Biofertilizer
D) Biocontrol agent

Answer 1

Hint: Symbiotic relationship exists between fungi and algae. They have a fungus and an alga living together and working for themselves. The algal partner is engaged in the process of photosynthesis while the fungal partner provides protection to the algae from the environment (mostly from moisture). They can be spotted as crusty patches or bushy growths on trees, rocks and bare ground.

Complete answer:
>Lichens are mutual collaborations of fungus and an alga/cyanobacterium. We can see that the symbiotic association does not exist between a fungus and the roots. Hence, this option is not correct.
>A Mycorrhiza is also known as a ‘root fungus’. It forms a symbiotic association with plant roots. Here, the fungi are actually integrated in the root.
Biofertilizers are mainly found in the symbiotic relationships between bacteria, fungi, and cyanobacteria (blue-green algae). The symbiosis between Rhizobium and leguminous roots, Azolla and Anabaena are a few examples of biofertilizers. This is not the correct answer too.
>Biocontrol agents can be defined as the utilization of natural enemies to reduce the damage caused by noxious organisms to tolerable levels. It relies on predation, parasitism, herbivory or other natural mechanisms, but typically also involves an active human management role. We can see that these are kind of plants and animals that help to keep damage caused by noxious organisms at bay. Thus, this is not the correct answer as well.

Therefore, the correct answer to this question is option B (Mycorrhiza).

Note:Mycorrhizae are located in the roots of vascular plants, but mycorrhiza-like associations also occur in bryophytes and there is fossil evidence that early land plants that lacked roots formed arbuscular mycorrhizal associations. Most plant species form mycorrhizal associations, though some families like Brassicaceae and Chenopodiaceae cannot. Different forms for the association are detailed in the next section. The most common is the arbuscular type that is present in 70% of plant species, including many crop plants such as wheat and rice.