Are ectomycorrhizal fungi actually adapting to 5 years of extreme summer drought in Middle European forests?

2021 ◽  
Author(s):  
Fabian Weikl ◽  
Karin Pritsch
Keyword(s):  
Enzyme Activities ◽  
Time Frame ◽  
Beech Forest ◽  
Functional Adaptation ◽  
Root Tip ◽  
Summer Drought ◽  
Root Tips ◽  
Roof Experiment ◽  
Fungal Symbiosis ◽  
The Impact

<p>Middle Europe’s forests face an increasing risk of recurring summer droughts. To explore the impact of such conditions, trees in a mature spruce-beech forest were exposed to five successive years of extreme summer drought during the Kranzberg Roof Experiment located in Bavaria (Grams et al. 2021, DOI: 10.1002/ecs2.3399).</p><p>Those trees (<em>Picea abies</em> and <em>Fagus sylvatica</em>) heavily depend on their ectomycorrhizal fungal symbiosis partners (ECMf) belowground. Thus, we set out to identify modes of compositional and functional adaptation in these communities.</p><p>We monitored ECMf communities via metabarcoding and analysed the functionality of morphotyped ectomycorrhizae via testing their enzyme activities.</p><p>To our surprise, most effects were quantitative throughout the whole period. Total enzyme activities strongly declined alongside the numbers of vital root tips of drought treated trees, while enzyme activities per surviving root tip remained remarkably similar to controls. Likewise, ECMf communities only experienced minor shifts that only slightly increased during the years, although different capacities for drought tolerance in ECMf have previously been hypothesised.</p><p>Summed up: Along with most tree individuals, their fungal partners showed a strong ability to resist the applied extreme drought scenario, at the cost of severely diminished capacities at the ecosystems level.</p><p>Speculatively, individual root tips could be seen as surviving insulae whose fungal communities only experienced indirect and moderated drought effects. Therefore, the ECM system may rather show an inherent resistance to drought, with observable qualitative adaptation requiring a still longer time-frame.</p>

Unperturbed root fungal communities in a temperate forest recovering from five years of reoccurring droughts 

2021 ◽  
Author(s):  
Jasmin Danzberger ◽  
Ramona Werner ◽  
Fabian Weikl ◽  
Karin Pritsch
Keyword(s):  
Drought Resistance ◽  
European Beech ◽  
Vegetation Period ◽  
Time Frame ◽  
Fungal Communities ◽  
Its2 Region ◽  
Root Tips ◽  
Average Temperature ◽  
Roof Experiment ◽  
Middle Europe

<p>Since industrialization, the global average temperature increases with far reaching consequences for the world climate. One phenomenon is the current occurrence of more heavy and long droughts in Middle Europe, which lead to extensive tree die-off and shows that we need a better understanding of the forest-soil ecosystem in times of climate change.</p><p>Within the interdisciplinary Kranzberg Roof Experiment, we study the drought resistance and drought recovery of mature Norway spruce (<em>Picea abies</em>) and European beech (<em>Fagus sylvatica</em>). The trees experienced a rainfall exclusion for five years during the vegetation period and were rewetted by drip irrigation in summer 2019. Our interest focuses in the functional role of ectomycorrhizal and overall fungal communities on tree drought resistance and recovery. Particularly, we hypothesized the rewetting event will lead to a shift in community structure because of steeply rising water and nutrient availabilities.</p><p>To get insights to the development of the fungal communities right after the rewetting period, we sequenced the fungal ITS2 region of fine root DNA extracts. The roots were taken from soil cores before and at several time-points after irrigation.</p><p>We found that the fungal communities stayed quite similar to each other during the time-frame of recovery we investigated (84 days), while the amount of new root tips strongly increased directly after the rewetting. Surprisingly, the organic material which had accumulated as it was not degraded during the years of drought, did not lead to a shift in community composition. In particular, there were no changes in the relative amounts of saprotroph fungi in the phase after the rewetting.</p><p>Therefore, root fungal communities – the interface between trees and soil – seemingly did not experience a strong pressure to adapt their composition to the new condition, which matches their resistant behavior during the long drought phase before (cf. abstract 2937).</p>

scholarly journals Comparisons of Root Morphology in Susceptible and Tolerant Melon Cultivars before and after Infection by Monosporascus cannonballus

HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 681-683 ◽  
Author(s):  
Kevin Crosby ◽  
David Wolff ◽  
Marvin Miller
Keyword(s):  
Root Length ◽  
Root Rot ◽  
Growth Period ◽  
Root Systems ◽  
Root Tip ◽  
Total Root Length ◽  
Root Tips ◽  
Monosporascus Cannonballus ◽  
Vine Decline ◽  
The Impact

The fungus Monosporascus cannonballus Pollock and Uecker infects melon (Cucumis melo L.) roots and causes root rot/vine decline disease, which has reduced productivity of commercial muskmelon and honeydew cultivars in South Texas. To assess the impact of the fungus on several root traits, two greenhouse experiments were carried out over two seasons. A comparison of inoculated vs. control root systems was carried out with four melon cultivars representing both susceptible (`Magnum 45' and `Caravelle') and tolerant types (`Deltex' and `Doublon'). The sand medium was inoculated with 50–60 colony forming units (CFUs) per gram of the severe Monosporascus strain, TX90-25. After a 30-day growth period, the control and inoculated root systems were carefully cleaned and evaluated. Roots were scanned by a computer and the data were analyzed by the Rhizo Pro 3.8 program. The traits of interest included total root length, average root diameter, number of root tips, number of fine roots (0–0.5 mm), and number of small roots (0.5–1 mm). Significant differences existed between the two tolerant cultivars and the two susceptible ones for four of the traits. Total root length, fine and small root length, and root tip number were greater for `Deltex' than for both susceptible cultivars and greater for `Doublon' than for `Caravelle'. The results suggest that tolerance to this pathogen is closely linked to the integrity of the root structure. The potential for improving root vigor to combat root rot/vine decline merits further investigation.

scholarly journals Distinct changes in mature root and growing root tip proteomes underlie physiological responses of bread wheat to salinity stress

2021 ◽  
Author(s):  
Bhagya M Dissanayake ◽  
Christiana Staudinger ◽  
Rana Munns ◽  
Nicolas L Taylor ◽  
A. Harvey Millar
Keyword(s):  
Protein Synthesis ◽  
Tca Cycle ◽  
Wheat Root ◽  
Root Tip ◽  
Root Tips ◽  
Wheat Roots ◽  
Root Tissues ◽  
Related Proteins ◽  
The Impact ◽  
Mature Root

The impact of salinity on wheat plants is often studied by analysis of shoot responses, even though the main mechanism of tolerance is shoot Na+ exclusion. There is a need to understand the molecular responses of root tissues that directly experience rising NaCl concentrations. We have combined analysis of root growth, ion content and respiration with proteome responses in wheat root tip and mature root tissues under saline conditions. We find significant changes in translation and protein synthesis, energy metabolism and amino acid metabolism in a root tissue specific manner. Translation and protein synthesis related proteins showed significant decreases in abundance only in root tips, as did most of the glycolytic enzymes and selected TCA cycle enzymes and ATP synthase subunits. This selective root tip proteome response indicates protein synthesis capacity and energy production were impaired under salt stress, correlating with the anatomical response of roots and reduced root tip respiration rate. Wheat roots respond directly to soil salinity, therefore shoot responses such as reduction in shoot growth and photosynthetic capacity need to be considered in light of these effects.

scholarly journals Impact of an 8-Year-Old Transgenic Poplar Plantation on the Ectomycorrhizal Fungal Community

2009 ◽  
Vol 75 (23) ◽  
pp. 7527-7536 ◽  
Author(s):  
Franck O. P. Stefani ◽  
Jean-Marc Moncalvo ◽  
Armand Séguin ◽  
Jean A. Bérubé ◽  
Richard C. Hamelin
Keyword(s):  
Fungal Community ◽  
Mineral Soil ◽  
Root Tip ◽  
Root Tips ◽  
Soil Dna ◽  
Fungal Community Structure ◽  
Β Diversity ◽  
Long Term Impact ◽  
The Impact

ABSTRACT The long-term impact of field-deployed genetically modified trees on soil mutualistic organisms is not well known. This study aimed at evaluating the impact of poplars transformed with a binary vector containing the selectable nptII marker and β-glucuronidase reporter genes on ectomycorrhizal (EM) fungi 8 years after field deployment. We generated 2,229 fungal internal transcribed spacer (ITS) PCR products from 1,150 EM root tips and 1,079 fungal soil clones obtained from the organic and mineral soil horizons within the rhizosphere of three control and three transformed poplars. Fifty EM fungal operational taxonomic units were identified from the 1,706 EM fungal ITS amplicons retrieved. Rarefaction curves from both the root tips and soil clones were close to saturation, indicating that most of the EM species present were recovered. Based on qualitative and/or quantitative α- and β-diversity measurements, statistical analyses did not reveal significant differences between EM fungal communities associated with transformed poplars and the untransformed controls. However, EM communities recovered from the root tips and soil cloning analyses differed significantly from each other. We found no evidence of difference in the EM fungal community structure linked to the long-term presence of the transgenic poplars studied, and we showed that coupling root tip analysis with a soil DNA cloning strategy is a complementary approach to better document EM fungal diversity.

Effects of partial cutting on the ectomycorrhizae of Picea glauca forests in northwestern Alberta

2005 ◽  
Vol 35 (6) ◽  
pp. 1442-1454 ◽  
Author(s):  
Lance W Lazaruk ◽  
Gavin Kernaghan ◽  
S Ellen Macdonald ◽  
Damase Khasa
Keyword(s):  
Picea Glauca ◽  
Effective Means ◽  
White Spruce ◽  
Root Tip ◽  
Root Tips ◽  
Partial Cutting ◽  
Disturbance Intensity ◽  
Tree Retention ◽  
Green Tree Retention ◽  
The Impact

This study assessed the impact of various harvesting practices (including those designed to emulate natural disturbances) on ectomycorrhizae (ECM) associated with white spruce (Picea glauca (Moench) Voss) in northwestern Alberta, Canada. Treatments included clearcuts, partial cuts (dispersed green-tree retention with 20%, 50%, and 75% residual live trees, and aggregated green-tree retention), unharvested control sites, and a burned stand. The percentage of active white spruce root tips and ECM richness and diversity, as observed in soil cores collected throughout the study site, all decreased with increasing disturbance intensity. Effects were particularly pronounced in clearcuts, machine corridors used for access by harvesting equipment in the dispersed green-tree retention stands, and in burned areas. Reductions in ECM biodiversity could be attributed to the sensitivity of late-stage ectomycorrhizae (e.g., Cortinarius spp., Lactarius spp., and Russula spp.) to soil disturbances and changes in microclimate associated with harvesting or burning. Areas of dispersed and aggregated green-tree retention were not dramatically different than unharvested forest in terms of root tip density and ECM richness, diversity, and composition. Harvesting practices that retain a percentage of residual live trees, either dispersed throughout the cutting unit or in aggregated patches, could be an effective means of maintaining ectomycorrhizal biodiversity at the stand level.

Coming-of-Age Cinema in New Zealand

2017 ◽  
Author(s):  
Alistair Fox
Keyword(s):  
Coming Of Age ◽  
Belief Systems ◽  
Time Frame ◽  
New Wave ◽  
Art Cinema ◽  
Literary Sources ◽  
French New Wave ◽  
Significant Phenomenon ◽  
The Impact ◽  
New Zealanders

This book investigates the coming-of-age genre as a significant phenomenon in New Zealand’s national cinema, tracing its development from the 1970s to the present day. A preliminary chapter identifies the characteristics of the coming-of-age film as a genre, tracing its evolution and the influence of the French New Wave and European Art Cinema, and speculating on the role of the genre in the output of national cinemas. Through case studies of fifteen significant films, including The God Boy, Sleeping Dogs, The Scarecrow, Vigil, Mauri, An Angel at My Table, Heavenly Creatures, Once Were Warriors, Rain, Whale Rider, In My Father’s Den, 50 Ways of Saying Fabulous, Boy, Mahana, and Hunt for the Wilderpeople, subsequent chapters examine thematic preoccupations of filmmakers such as the impact of repressive belief systems and social codes, the experience of cultural dislocation, the expression of a Māori perspective through an indigenous “Fourth Cinema,” bicultural relationships, and issues of sexual identity, arguing that these films provide a unique insight into the cultural formation of New Zealanders. Given that the majority of films are adaptations of literary sources, the book also explores the dialogue each film conducts with the nation’s literature, showing how the time frame of each film is updated in a way that allows these films to be considered as a register of important cultural shifts that have occurred as New Zealanders have sought to discover their emerging national identity.

Method development for the determination of textural properties of sugar beet roots

2019 ◽  
pp. 392-400 ◽  
Author(s):  
Gunnar Kleuker ◽  
Christa M. Hoffmann
Keyword(s):  
Sugar Beet ◽  
Compression Test ◽  
Storage Period ◽  
Textural Properties ◽  
Small Sample ◽  
Root Tip ◽  
Flexural Test ◽  
Sample Distribution ◽  
The Impact

The harvest of sugar beet leads to root tip breakage and surface damage through mechanical impacts, which increase storage losses. For the determination of textural properties of sugar beet roots with a texture analyzer a reliable method description is missing. This study aimed to evaluate the impact of washing, soil tare, storage period from washing until measurement, sample distribution and number of roots on puncture and compression measurements. For this purpose, in 2017 comprehensive tests were conducted with sugar beet roots grown in a greenhouse. In a second step these tests were carried out with different Beta varieties from a field trial, and in addition, a flexural test was included. Results show that the storage period after washing and the sample distribution had an influence on the puncture and compression strength. It is suggested to wash the roots by hand before the measurement and to determine the strength no later than 48 h after washing. For reliable and comparable results a radial distribution of measurement points around the widest circumference of the root is recommended for the puncture test. The sample position of the compression test had an influence on the compressive strength and therefore, needs to be clearly defined. For the puncture and the compression test it was possible to achieve stable results with a small sample size, but with increasing heterogeneity of the plant stand a higher number of roots is required. The flexural test showed a high variability and is, therefore, not recommended for the analysis of sugar beet textural properties.

Histochemical Examination of Invertase Activities in the Growing Tip of the Plant Root

2017 ◽  
Vol 10 (1) ◽  
pp. 35-45
Author(s):  
N.F. Lunkova ◽  
N.A. Burmistrova ◽  
M.S. Krasavina
Keyword(s):  
Plant Root ◽  
Invertase Activity ◽  
Root Tip ◽  
Elongation Zone ◽  
Root Tips ◽  
Phloem Unloading ◽  
Meristem Cell ◽  
Transition To Elongation ◽  
Different Tissues

Background:A growing part of the root is one of the most active sinks for sucrose coming from source leaves through the phloem. In the root, sucrose is unloaded from conducting bundles and is distributed among the surrounding cells. To be involved in the metabolism, sucrose should disintegrate into hexoses by means of degrading enzymes.Aims:The aim of this research was to explore the possibility of the involvement of one such enzymes, invertase, in phloem unloading as well as distribution of its activity in the functionally different tissues of the plant root tips.Method:To estimate the enzyme activities in root tissues, we applied two techniques: the histochemical method using nitro blue tetrazolium. The localization of phloem unloading was studied with carboxyfluorescein, a fluorescent marker for symplastic transport.Results:Invertase activity was not detected in the apical part of the meristem. It appeared only between the basal part of this zone and the beginning of the elongation zone. There is the root phloem unloading in that area. Invertase activity increased with increasing the distance from the root tip and reached the highest values in the region of cell transition to elongation and in the elongation zone. The activities of the enzyme varied in different tissues of the same zone and sometimes in the neighboring cells of the same tissue. Biochemical determination of invertase activity was made in the maize root segments coincident to the zones of meristem, cell elongation and differentiation. The results of both methods of determination of invertase activity were in agreement.Conclusion:It was concluded that phloem unloading correlated with invertase activity, possibly because of the activation of invertase by unloaded sucrose. Invertase is one of the factors involved in the processes preparing the cells for their transition to elongation because the concentration of osmotically active hexoses increases after cleavage of sucrose, that stimulates water entry into the cells, which is necessary for elongation growth.

scholarly journals Effect of earthworms on mycorrhization, root morphology and biomass of silver fir seedlings inoculated with black summer truffle (Tuber aestivum Vittad.)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tina Unuk Nahberger ◽  
Gian Maria Niccolò Benucci ◽  
Hojka Kraigher ◽  
Tine Grebenc
Keyword(s):  
Root System ◽  
Root Biomass ◽  
Fine Root ◽  
Abies Alba ◽  
Fine Root Biomass ◽  
Root Tip ◽  
Silver Fir ◽  
Tuber Aestivum ◽  
Root Tips ◽  
Root Parameters

AbstractSpecies of the genus Tuber have gained a lot of attention in recent decades due to their aromatic hypogenous fruitbodies, which can bring high prices on the market. The tendency in truffle production is to infect oak, hazel, beech, etc. in greenhouse conditions. We aimed to show whether silver fir (Abies alba Mill.) can be an appropriate host partner for commercial mycorrhization with truffles, and how earthworms in the inoculation substrate would affect the mycorrhization dynamics. Silver fir seedlings inoculated with Tuber. aestivum were analyzed for root system parameters and mycorrhization, how earthworms affect the bare root system, and if mycorrhization parameters change when earthworms are added to the inoculation substrate. Seedlings were analyzed 6 and 12 months after spore inoculation. Mycorrhization with or without earthworms revealed contrasting effects on fine root biomass and morphology of silver fir seedlings. Only a few of the assessed fine root parameters showed statistically significant response, namely higher fine root biomass and fine root tip density in inoculated seedlings without earthworms 6 months after inoculation, lower fine root tip density when earthworms were added, the specific root tip density increased in inoculated seedlings without earthworms 12 months after inoculation, and general negative effect of earthworm on branching density. Silver fir was confirmed as a suitable host partner for commercial mycorrhization with truffles, with 6% and 35% mycorrhization 6 months after inoculation and between 36% and 55% mycorrhization 12 months after inoculation. The effect of earthworms on mycorrhization of silver fir with Tuber aestivum was positive only after 6 months of mycorrhization, while this effect disappeared and turned insignificantly negative after 12 months due to the secondary effect of grazing on ectomycorrhizal root tips.

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