We are pleased to announce that Akshit Puri successfully defended his examination for the degree of Doctor of Philosophy in Soil Science on May 11, 2020!
Title: Evaluating the comprehensive ecological role of endophytic nitrogen-fixing bacteria in sustaining the growth of boreal forest trees on nutrient-poor soils
Thesis Summary: In natural ecosystems, plants associate with beneficial microbes that play a crucial role in enhancing their growth and health, particularly on disturbed soils. Although mostly unexplored, beneficial bacteria living inside the plant tissues could be an important source of nutrition and development for plants growing in such conditions. In this thesis, the presence and possible role(s) of such endophytic bacteria were explored in lodgepole pine and hybrid white spruce trees growing on extremely nutrient-limited soils in central interior of British Columbia. These bacteria were able to enhance tree growth under nutrient-stress conditions by potentially employing various mechanisms to acquire plant-inaccessible nutrients, modulate plant hormone levels and control plant pathogen populations. Most importantly, these bacteria were observed to provide nitrogen nutrition to trees by directly fixing N2 from the atmosphere. In future, these bacteria could potentially be used as biofertilizers for trees, thereby representing a low-cost, environment-friendly alternative to chemical fertilizers.