UBC Theses and Dissertations
Comparative response of six grapevine rootstocks to inoculation with arbuscular mycorrhizal fungi based on root traits Pogiatzis, Antreas
Arbuscular mycorrhizal fungi are soil fungi that form a symbiotic association with plant roots. The symbiosis is largely nutritional. The fungi depend on the plants for carbon resources, and the plants benefit from increased access to soil nutrients. The magnitude of plant benefit, however, can vary significantly. Understanding the factors that influence plant growth response is important, especially in agroecosystems where high yield is desirable. It has been suggested that root architecture is a key factor that determines plant responsiveness to arbuscular mycorrhizal fungi, and some studies have been conducted and support this notion. However, a major limitation in such studies is the lack of control for phylogenetic constraints among tested plants, making it difficult to control for confounding variables that are not associated with root architecture. In this dissertation, I explored the variation in plant responsiveness among closely related species (all grapevines) and investigated the potential relationship between root architecture and responsiveness to arbuscular mycorrhizal fungi. I found that root colonization by arbuscular mycorrhizal fungi can improve grapevine growth, although the degree of growth responses differed among grapevine cultivars. The magnitude of the benefit (plant growth response to a fungi) can be partially explained by the pre-colonization root architecture, and in particular with branching intensity, which is largely associated with plant nutrient foraging ability. However, root architecture alone is a poor predictor of plant response to arbuscular mycorrhizal fungi and more factors need to be considered to better understand plant nutrient foraging ability. In addition, mycorrhizas can influence the expression of root traits, such as root branching intensity, average root diameter and the root to shoot ratio.
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