SOE 306 Announcements Lecture 17 Plant symbioses with fungi and bacteria Quiz 17 due Wed 4 26 Bonus Quiz available due 5 1 Today Lecture 17 Wed 4 26 Discussion Mycorrhizae and the Wood Wide Web Wed 4 28 Discussion The most interesting thing about plants Exam 3 part 1 mean score 84 part 2 mean 94 overall mean 88 Many papers graded Final exam available Wednesday 4 26 Due Thursday May 4th Content 50 on material since exam 3 Lecs 14 15 16 17 50 on prior material Outline 1 Mycorrhizae types and structures 2 Mycorrhizal interactions 1 3 Mycorrhizal interactions 2 4 The Wood Wide Web 5 N fixing bacteria Symbiosis in Ecology Symbiosis a close and long term interaction between two organisms Mutualism interaction between two or more species where each benefit Symbiotic relationships can be mutualism parasitism or commensalism Symbiosis in Ecology Symbiosis a close and long term interaction between two organisms Mutualism interaction between two or more species where each benefit Symbiotic relationships can be mutualism parasitism or commensalism Benefits of Mycorrhizal Association For plant For fungus Food source carbohydrates Amino acids Increased nutrient uptake Increased water uptake Protection from root pathogens and herbivores Increased plant growth Mycorrhizas greatly extend the root network Types of mycorrhizae Types of mycorrhizae AM grow inside plant root cells ECM grow between and around root cells Arbuscular Mycorrhiza Development Strigolactones plant signaling compounds hormones for plant fungi recognition Arbuscle site of exchange Arbuscules Plant Benefits of AM Colonization Jacott et al 2017 Ectomycorrhizae Amanita muscaria on Pinus radiata Suillus brevipes on Pinus radiata Ectomycorrhizae Unknown fungus Roots Pinus resinosa Red pine Hartig net Mantle Pisolithus tinctorius Pisolithus tinctorius Fruiting body of an Ectomycorrhizal fungi Amanita muscaria fly agaric Outline 1 Mycorrhizae types and structures 2 Mycorrhizal interactions 1 3 Mycorrhizal interactions 2 4 The Wood Wide Web 5 N fixing bacteria Nutrients from Mycorrhizae Ectomycorrhizae organic inorganic nutrients Arbuscular Mycorrhizae inorganic nutrients only Mycorrhizal P uptake Experimental demonstration of mycorrhizal P uptake AM effect on plant growth Trifolium subterraneum Burrowing clover Mycorrhizal Dependency More growth w myco Plant benefit or not depends on plant species and fungal species Linum usitatissimum flax Medicago truncatula medic Solanum lycopersicum tomato More P with myco Less growth with mycorrhizae Less P with mycorrhizae Prevalence of mycorrhizal relationships across soils Cluster roots In low P soils fungi cannot separate Phosphate ions from soil particles as well as cluster roots Mycorrhizal Suppression Increased with P supply Casuarina cunninghamiana River she oak Ectomycorrhizae can provide N Outline 1 Mycorrhizae types and structures 2 Mycorrhizal interactions 1 3 Mycorrhizal interactions 2 4 The Wood Wide Web 5 N fixing bacteria Mycorrhizal N transfer among plants M mycorrhizae M no mycorrhizae F N fixing bacteria F no N fixing bacteria Labelling compartment Mycorrhizal Transfer of C from plant to plant Klein et al 2016 Mycorrhizal Networks only top 30 species shown fungi on all 4 tree species 13C Labelling Experiment Rog et al 2018 Mycorrhizal Networks only top 30 species shown EMF Community Similarity fungi on all 4 tree species Rog et al 2018 Mycorrhizal Networks only top 30 species shown fungi on all 4 tree species Rog et al 2018 Mycorrhizal Diversity Plant Diversity Plant macrocosm experiment Simulated old field in pots Vand der Heijden et al 1998 Mycorrhizal Diversity Plant Diversity Tibetan Plateau Grasslands China Yang et al 2017 Mycoheterotrophy Plant s ability to obtain C from fungi Merckx et al 2013 Mycoheterotrophy Mycorrhizal cheaters facultative obligate Monotropa uniflora Ghost pipe Cephalanthera damasonium White helleborine an orchid Mycoheterotrophy faculative Non Plants along an evolutionary gradient Cephalanthera damasonium White helleborine Capacity for electron transport Albino phenotype Hynson et al 2013 Outline 1 Mycorrhizae types and structures 2 Mycorrhizal interactions 1 3 Mycorrhizal interactions 2 4 The Wood Wide Web 5 N fixing bacteria Wood wide web Mycorrhizal Transfer of C from plant to plant Figure 1 Mean s e net transfer from B papyrifera to P menziesii in deep shade partial shade and full ambient sunlight in the first two year old seedlings open circles and second three year old seedlings filled circles experiment years Simard et al 1997 Artist Elizabeth Malsin The most astonishing thing about trees is how social they are The trees in a forest care for each other sometimes even going so far as to nourish the stump of a felled tree for centuries after it was cut down by feeding it sugars and other nutrients and so keeping it alive Only some stumps are thus nourished Perhaps they are the parents of the trees that make up the forest of today When trees grow together nutrients and water can be optimally divided among them all so that each tree can grow into the best tree it can be When you know that trees experience pain and have memories and that tree parents live together with their children then you can no longer just chop them down and disrupt their lives Trees could solve the problems if people trying to improve things would only allow them to take over Wood wide web The socialist forest trees act as caregivers to one another Or The capitalist forest trees act out of self interest in a competitive system Has the Hype outpaced the Science Karst et al 2023 Yes Justine Karst Has the Hype outpaced the Science Main points of Karst et al 2023 1 Insufficient evidence that mycorrhizal networks and plant to plant transfer are widespread in nature Wood Wide Web Has the Hype outpaced the Science Main points of Karst et al 2023 1 Insufficient evidence that mycorrhizal networks and plant to plant transfer are widespread in nature Wood Wide Web 2 There is no peer reviewed evidence shows that mature trees in forests preferentially send resources or signals to their offspring Mother Trees Has the Hype outpaced the Science Main points of Karst et al 2023 1 Insufficient evidence that mycorrhizal networks and plant to plant transfer are widespread in nature Wood Wide Web 2 There is no peer reviewed evidence shows that mature trees in forests preferentially send resources or signals to their offspring Mother Trees 3 Unsupported claims have doubled in literature and