Some plants may depend more on friendly fungi than own leaves: Study

Researchers have found that plants need the help of friendly fungi to thrive more than it depends on the quality of its own leaves, and on bacteria that adds nitrogen nutrients to the soil. The researchers, including those from the University of Tennessee in the US, found that certain root-associated, or mycorrhizal, fungi that associate firmly with the cells in plant roots are one of the largest influences on plant tissue nutrient concentrations.

The study, published in the journal PNAS, noted that there are two main types of mycorrhizal fungi -- arbuscular and ectomycorrhizal. An arbuscular mycorrhiza, the researchers said, penetrates the cells in the outer layer of the roots of a plant.

Ectomycorrhizal fungi, they said, do not penetrate the plant's cell walls, instead of forming a netlike structure around the plant root. According to the researchers, arbuscular mycorrhizal fungi increased plant nutrient concentrations in plant leaves, litter, and roots more than the non-penetrating counterparts, and has more influence on a plant's nutrient levels than plant leaf traits, or plant associations with nitrogen-fixing bacteria.

The researchers analyzed more than 17,000 traits from nearly 3,000 woody plant species in six categories and observed how readily the plant uses nutrients: nitrogen and phosphorus concentrations in green leaves, senescent leaves (leaves that are about to fall off or have recently fallen off), and roots. The researchers said that plants live in symbiosis with the root-associated fungi which provide up to 80 percent of the nutrients and water a plant needs to grow.

They added that up to 30 percent of the food substance the plants make through photosynthesis is needed by the fungi. "To optimize plant nutrition, we need to incorporate mycorrhizal associations into our agricultural and management frameworks," said study co-author Stephanie Kivlin from the University of Tennessee.