PS 47-135 - Plants and parenthood: Do plants facilitate the success of their own offspring through a shared mycorrhizal network?

Wednesday, August 10, 2011
Exhibit Hall 3, Austin Convention Center
David J. Burke, The Holden Arboretum, Kirtland, OH

Biotic interactions that occur in plant communities can either promote or hinder plant growth and one of the most important is the mutually beneficial relationships that form between plants and arbuscular mycorrhizal fungi (AMF). AMF act as an extension of the root system increasing plant nutrient gain.  Many AMF will colonize a large number of plant species and individuals simultaneously resulting in a belowground network of hyphae connecting the roots of many plants. Plant seedlings can become quickly colonized by this hyphal network, which may allow seedlings to acquire nutrients without having to spend as much carbon on the mycorrhizal fungi, leading to enhanced seedling growth.  In this study I hypothesized that 1) seedlings connected to a mycorrhizal network will experience increased growth and nutrient acquisition and 2) seedlings connected to a mycorrhizal network established by an adult plant of the same species would benefit more than seedlings of another species and experience a “parental effect”. To examine these hypotheses, I established a greenhouse study that manipulated seedling access to the mycorrhizal network in the presence of either an adult plant of the same or different species.  Seedling biomass, nutrient content and mycorrhizal colonization were measured after 2 growing seasons. 


Generally, seedlings of Arisaema triphyllum (Jack in the pulpit) had significantly more biomass than seedlings of Maianthenum racemosum (False Solomon’s seal).  Biomass of Arisaema seedlings was not affected by the identity of the adult plant (Arisaema triphyllum or Maianthenum racemosum) or colonization by mycorrhizal fungi. For Maianthenum seedlings, I found a significant interaction between the identity of the adult plant and mycorrhizal colonization for leaf biomass (P = 0.037), rhizome biomass (P = 0.015), below and above ground biomass (P = 0.036 and 0.047) and total biomass (P = 0.029). Total leaf nitrogen of Maianthenum seedlings was also significantly affected by the interaction between adult plant identity and mycorrhizal colonization (P = 0.020). Pairwise comparisons found that biomass of mycorrhizal Maianthenum seedlings grown near a Maianthenum adult was greater than mycorrhizal seedlings grown near an Arisaema adult, and when Maianthenum seedlings were grown near an Arisaema adult the mycorrhizal seedlings had significantly less biomass than non-mycorrhizal seedlings.  This suggests that the seedling benefit from the mycorrhizal network depends on the identity of the adult plant, with some plants conferring positive and others negative effects on mycorrhizal as compared to non-mycorrhizal seedlings.

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