Q31.3-2CC. - Campbell Biology

Question

Describe the importance of mycorrhizae, both today and in the colonization of land. What evidence supports the antiquity of mycorrhizal associations?

Step-by-Step Solution

Answer

Mycorrhizae can absorb the soils’ nutrients more efficiently than the plants’ absorption of the nutrients from the ground. In simple words, mycorrhizae increase the uptake of both nutrients, along with water.

Due to the presence of mycorrhiza, plants do not get affected by the water stress, and it also increases the plants’ growth. Mycorrhiza is essential for the production of biomass and crops.

Step 1: Mycorrhizae

Mycorrhizae have a role in plant nutrition, and it describes fungi’s role in the rhizosphere of the plants. Mycorrhiza is an example of mutual benefits that occur between host plants and fungi. 

A mycorrhiza helps plants to reach the nutrients that are generally impossible for them to get.

Step 2: Mycorrhizae location

Generally, in the vascular plant’s roots, mycorrhizae are present. Evidence (in the form of fossil) indicates that in earlier times, land plants without roots or in the absence of roots developed arbuscular mycorrhizal associations.

The mycorrhizal fungus is found in soil, and is associated with the plant’s roots. Apart from arbuscular mycorrhizae, other types of mycorrhizal associations are i) orchid, ii) ectomycorrhiza, and iii) ericoid.

Step 3: Evidence of mycorrhizal associations

The existence of fossils shows arbuscular mycorrhizae in the land plants that had arrived earlier. The plant is known as Aglaophyton. Molecular results have indicated that genes are required during the formation of mycorrhizae, and these genes are present in liverworts.

Sometimes, other basal plant lineages have these genes too. Mycorrhizae are vital for the terrestrial plants’ evolutionary success to conquer the land.