What organisms participate in the intimate mutualistic relationship found in mycorrhiza?

Fungi and roots of higher plants

The correct answer is Option (2)- Fungi and roots of higher plants

Mycorrhizae represent an intimate mutualistic relationship between fungi and the roots of higher plants. In this symbiotic association, the fungi provide several benefits to the plant roots, while the plants, in turn, supply the fungi with energy-yielding carbohydrates.

The fungi in mycorrhizal associations form a network of fine, thread-like structures called hyphae that penetrate into the soil and surround the root cells of the plant. These hyphae greatly increase the surface area for nutrient absorption, enhancing the plant's ability to acquire essential nutrients from the soil. The fungi have a remarkable capacity to extract nutrients, such as phosphorus, nitrogen, and various micronutrients, from the soil and transport them to the plant roots.

In exchange for these nutrient-providing services, the plant supplies the fungi with carbohydrates, mainly in the form of sugars produced through photosynthesis. These energy-yielding carbohydrates are transferred from the plant to the fungi through specialized structures known as arbuscules or mycelium. The carbohydrates serve as a source of energy for the fungi, enabling their growth and metabolism.

The mutualistic relationship between fungi and plant roots in mycorrhizae is highly beneficial for both partners. The plants receive enhanced nutrient uptake capabilities, which are especially valuable in nutrient-deficient soils. This can lead to improved plant growth, development, and overall fitness. Additionally, mycorrhizal associations can provide benefits such as increased tolerance to drought, pathogens, and heavy metal toxicity.

On the other hand, the fungi benefit from the carbohydrates provided by the plants. The energy-rich carbohydrates allow the fungi to thrive and reproduce, supporting their survival and colonization in the soil. The fungi also benefit from the association by receiving protection and a relatively stable environment provided by the plant roots.

Overall, the mycorrhizal association between fungi and plant roots exemplifies a mutualistic relationship in which both partners derive significant benefits. The fungi assist the plant in nutrient uptake, while the plants supply the fungi with carbohydrates, establishing a symbiotic exchange that contributes to the growth and success of both organisms.