[Phosphorus transfer between mixed poplar and black locust seedlings]

Area of Science:

• Plant Biology
• Soil Science
• Mycology

Context:

• Investigating inter-species nutrient transfer in forest ecosystems.
• Understanding the role of vesicular-arbuscular (VA) mycorrhizal fungi in plant interactions.
• Utilizing radio-tracer techniques for nutrient movement studies.

Purpose:

• To determine the primary pathways of phosphorus transfer between poplar (Populus euramericana cv. 'I-214') and black locust (Robinia pseudoacacia).
• To assess the contribution of hyphal links versus direct root contact and exudations to phosphorus transfer.
• To evaluate the influence of VA mycorrhizal fungi (Glomus mosseae) on nutrient exchange.

Summary:

• The study employed a 32P radio-tracer in a compartmentalized root box to track phosphorus movement between poplar and black locust inoculated with Glomus mosseae.
• Results indicated that root contact and root exudations were the dominant pathways for phosphorus transfer, accounting for 62% of the total.
• Mycorrhizal activity, including VA mycorrhizal fungi, contributed 38% to phosphorus transfer, with direct hyphal links showing minimal direct nutrient transfer impact when separated by mesh.

Impact:

• Highlights the significant role of direct root interactions in nutrient sharing between tree species.
• Quantifies the relative contributions of different pathways (root contact, exudations, mycorrhizae) to inter-species phosphorus transfer.
• Provides insights into plant-fungal interactions and their implications for nutrient cycling in mixed stands.