Symbiotic association of fungi with plant are called as Mycorrhiza

Explanation:
Mycorrhizae are mutualistic associations between fungi and the roots of most vascular plants. This association is extremely important for both the fungi and the plants involved, as it provides various benefits to both parties.

Types of Mycorrhizae:
There are three main types of mycorrhizae:

1. Ectomycorrhizae:
- In this type of mycorrhizae, the fungal hyphae form a sheath around the roots (ecto- means outside).
- The hyphae also penetrate between root cells but do not enter the cells.
- Ectomycorrhizae are commonly found in trees, such as pines, oaks, and birches.

2. Arbuscular Mycorrhizae:
- In this type of mycorrhizae, the fungal hyphae penetrate the cortical cells of the roots and form highly branched structures called arbuscules.
- Arbuscular mycorrhizae are found in a wide range of plants, including crops like wheat, corn, and rice.

3. Ericoid Mycorrhizae:
- This type of mycorrhizae is specialized for plants in the Ericaceae family, which includes heather, blueberries, and cranberries.
- The fungal hyphae grow between and within the cells of the roots, but do not form arbuscules.

Benefits of Mycorrhizae:

1. Nutrient Exchange:
- The fungal hyphae have a much greater surface area than the plant roots, which allows them to absorb nutrients more efficiently.
- The fungi can transfer nutrients, such as phosphorus and nitrogen, from the soil to the plant roots, while the plants provide the fungi with carbohydrates.

2. Increased Absorption of Water:
- Mycorrhizal fungi can also improve the plant's ability to absorb water.
- The hyphae can explore a larger volume of soil, reaching areas that are inaccessible to plant roots alone.
- This helps the plant to better withstand drought conditions.

3. Protection against Pathogens:
- Mycorrhizae can also protect plants against pathogens by producing antibiotics or by competing with pathogenic fungi for resources.
- The association with mycorrhizal fungi enhances the plant's resistance to various diseases.

4. Improved Soil Structure:
- The growth of mycorrhizal fungi can improve soil structure by producing glomalin, a sticky protein that binds soil particles together.
- This increases soil stability and reduces erosion.

In conclusion, mycorrhizae are essential for the growth and survival of plants, as they provide numerous benefits, including nutrient exchange, improved water absorption, protection against pathogens, and improved soil structure.