Carbon use efficiency in mycorrhizas theory and sample calculations

Area of Science:

• Plant-fungal interactions
• Mycorrhizal symbiosis
• Carbon cycling in ecosystems

Background:

• Mycorrhizal associations involve nutrient exchange between fungi and host plants.
• Fungi gain carbon from hosts, while hosts receive nutritional benefits.
• Quantifying the carbon cost to the host is crucial for understanding symbiosis.

Purpose of the Study:

• To develop a model for calculating carbon use efficiency in mycorrhizal associations.
• To assess the economic balance of carbon exchange between host plants and fungi.
• To evaluate the impact of fungal carbon demand on plant growth.

Main Methods:

• Utilized ¹⁴C pulse-chase experiments and field turnover rate estimations.
• Developed a model based on economic principles of cost-benefit analysis.
• Measured carbon allocation and calculated carbon use efficiency in Salix viminalis.

Main Results:

• Carbon costs of mycorrhizal fungi were estimated using laboratory and field methods.
• A novel model defined efficiency based on carbon gained versus carbon expended.
• Calculated carbon use efficiency was high in Salix viminalis, averaging 85% (shoot) and 95% (whole plant).

Conclusions:

• Mycorrhizal associations can be highly carbon-efficient for host plants.
• The developed model provides a framework for assessing symbiont carbon costs.
• Understanding carbon use efficiency is key to plant growth and ecosystem function.