Effects of ectomycorrhizal fungi on water and nutrient availability to trees growing in mixed-species fungal communities

Details

Supervisors

Ponette, Quentin ; Declerck, Stephan

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en gestion des forêts et des espaces naturels, à finalité spécialisée

Abstract

Forests and trees play a vital role in Earth’s ecosystems and are essential for climate regulation. They also offer a wide range of benefits to human society by providing multiple ecosystem services. However, in an increasingly uncertain climate, these ecosystems are now facing an unprecedented frequency and intensity of disturbances. Increasing droughts is currently one of the predominant disturbances affecting tree stands and is already responsible directly or indirectly of multiple forest diebacks. In the complex interaction between plants and their environment, the mycorrhizal symbiosis plays a crucial role, affecting more than 86% of terrestrial plant species. Among these mycorrhizas, ectomycorrhizal fungi establish symbiotic relations with many tree species and are predominant in forests ecosystems. These fungi mainly belong to the homobasidiomycetes classification and are characterized by the formation of a mantle around trees root tips and a Hartig net, network of intercellular fungal hyphae. These symbionts can promote the development of their hosts, notably through improved nutrient and water uptake or protection against pathogens. Understanding the effects of ectomycorrhiza on drought-stressed trees is thus essential in the research of solutions to increase forests resistance and resilience to droughts. Through an experimental approach, this master’s thesis explores the influence of EcM fungal species diversity on tree seedlings’ resistance and resilience to drought stress. Two EcM fungal species, P. involutus and H. crustuliniforme, are inoculated on P. sylvestris seedlings to meet this research goal. The experiment involves two main phases : firstly, a drought phase to study the effects of EcM fungal species diversity on seedlings' resistance to drought. Secondly, this drought is followed by a recovery phase, to examine the resilience of the mycorrhized seedlings. Although the results of the experiment do not answer the initial research question on the influence of EcM fungal species diversity, this study offers nuanced results on the effects of H. crustuliniforme on P. sylvestris resistance and resilience to drought stress. Moreover, this experiment provides many valuable lessons for further research on the effect of EcM fungal species diversity on tree seedlings’ resistance and resilience to drought.