| Aspect | Details |
|---|---|
| Symbiotic Association | Mycorrhiza is a symbiotic relationship between fungi and plant roots. |
| Fungal Role in Mycorrhiza | The fungal filaments either form a network around young roots or penetrate root cells, significantly increasing the surface area for absorbing water and minerals. |
| Plant Benefits | Plants receive minerals (like phosphorus) and water from the fungus. Additionally, they gain resistance to root-borne pathogens, tolerance to salinity and drought, and improved growth. |
| Fungal Benefits | The fungus receives sugars and nitrogen-containing compounds from the plant. |
| Obligate Association Example | Some plants, like Pinus, have an obligate relationship with mycorrhiza, essential for their seed germination and establishment. |
| Examples of Fungal Genera | Many members of the genus Glomus form mycorrhiza, aiding in phosphorus absorption from the soil. |
| Assertion | Reason | Answer (True/False) |
|---|---|---|
| Mycorrhiza increases the surface area available for water and mineral absorption. | The fungal hyphae have a very large surface area, allowing absorption from a much larger volume of soil. | True |
| Some plants, like Pinus, require mycorrhizae to germinate and establish. | Pinus seeds have an obligate association with mycorrhizae, essential for their germination. | True |
| Fungi in mycorrhiza absorb phosphorus and transfer it to the plant. | Members of the genus Glomus form mycorrhizae that absorb phosphorus from the soil and pass it to the plant. | True |
| Mycorrhizae confer additional benefits to plants beyond nutrient absorption. | Plants with mycorrhizae show resistance to pathogens, tolerance to salinity and drought, and increased growth. | True |
| Aspect/Assertion | Details/Reason | Answer (True/False) |
|---|---|---|
| Symbiotic Association | Mycorrhiza is a symbiotic association between a fungus and plant roots. | True |
| Fungal Role in Mycorrhiza | The fungal filaments either form a network around the root or penetrate the root cells. | True |
| Increased Surface Area for Absorption | Mycorrhiza increases the surface area available for water and mineral absorption. | True |
| Mechanism | The fungal hyphae have a very large surface area, allowing absorption from a much larger volume of soil. | True |
| Obligate Association Example | Some plants, like Pinus, require mycorrhizae to germinate and establish. | True |
| Specific Association | Pinus seeds have an obligate association with mycorrhizae, essential for their germination. | True |
| Phosphorus Absorption and Transfer | Fungi in mycorrhiza absorb phosphorus and transfer it to the plant. | True |
| Fungal Genera Example | Members of the genus Glomus form mycorrhizae that absorb phosphorus from the soil and pass it to the plant. | True |
| Additional Plant Benefits | Mycorrhizae confer additional benefits to plants beyond nutrient absorption. | True |
| Enhanced Resistance and Tolerance | Plants with mycorrhizae show resistance to pathogens, tolerance to salinity and drought, and increased growth. | True |
| Fungal Benefits | The fungus receives sugars and nitrogen-containing compounds from the plant. | True |
| Aspect | Details |
|---|---|
| Evolution of Mycorrhiza | The mycorrhizal symbiosis is arguably the most important symbiosis on earth. Fossil records indicate that arbuscular mycorrhizal interactions evolved 400 to 450 million years ago and played a critical role in the colonization of land by plants. |
| Prevalence | Approximately 80% of all known land plant species form mycorrhizal interactions with ubiquitous soil fungi. |
| Mutually Beneficial Interaction | The majority of mycorrhizal interactions are mutually beneficial, characterized by a bidirectional exchange of resources across the mycorrhizal interface. |
| Nutrient Exchange | The mycorrhizal fungus provides the host plant with nutrients such as phosphate and nitrogen, while the plant transfers 4-20% of its photosynthetically fixed carbon to the fungus. |
| Stress Resistance | Mycorrhizal interactions increase the abiotic (drought, salinity, heavy metals) and biotic (root pathogens) stress resistance of the host plant. |
| Mycoheterotrophic Plants | Some mycoheterotrophic plants, which have lost their photosynthetic capabilities, rely on mycorrhizal fungi for their carbon supply, parasitizing fungi associated with neighboring autotrophic plants. |
| Mycoheterotrophic in Diverse Plant Families | Approximately 400 plant species from different plant families, such as bryophytes, pteridophytes, and angiosperms, exhibit mycoheterotrophy. |