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"Oak Life cycles."
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Mighty : the story of an oak tree ecosystem
\"This stunning, profound book explores the life cycle of a tree-not just through a season but across decades-as well as the other living things that depend upon it. How can something stay itself and yet change and grow? The oak tree shows us how\"-- Provided by publisher.
CHILDBOOK
Relationships between nitrogen cycling microbial community abundance and composition reveal the indirect effect of soil pH on oak decline
Tree decline is a global concern and the primary cause is often unknown. Complex interactions between fluctuations in nitrogen (N) and acidifying compounds have been proposed as factors causing nutrient imbalances and decreasing stress tolerance of oak trees. Microorganisms are crucial in regulating soil N available to plants, yet little is known about the relationships between soil N-cycling and tree health. Here, we combined high-throughput sequencing and qPCR analysis of key nitrification and denitrification genes with soil chemical analyses to characterise ammonia-oxidising bacteria (AOB), archaea (AOA) and denitrifying communities in soils associated with symptomatic (declining) and asymptomatic (apparently healthy) oak trees (
Quercus robur
and
Q. petraea
) in the United Kingdom. Asymptomatic trees were associated with a higher abundance of AOB that is driven positively by soil pH. No relationship was found between AOA abundance and tree health. However, AOA abundance was driven by lower concentrations of NH
4
+
, further supporting the idea of AOA favouring lower soil NH
4
+
concentrations. Denitrifier abundance was influenced primarily by soil C:N ratio, and correlations with AOB regardless of tree health. These findings indicate that amelioration of soil acidification by balancing C:N may affect AOB abundance driving N transformations, reducing stress on declining oak trees.
Journal Article
Squirrel's family tree
\"What makes an oak tree an oak tree and what makes a squirrel a squirrel? In [this book], things aren't always what they seem. As squirrel searches for, finds, and hides her acorn treasures beneath the shadows of the great oak trees in the forest, little does she know the role she plays in creating the very environment she forages in\"-- Provided by publisher.
Book
ChIP-Seq reveals that QsMYB1 directly targets genes involved in lignin and suberin biosynthesis pathways in cork oak (Quercus suber)
TC and VI were supported by Fundação para a Ciência e a Tecnologia (FCT) through the PhD grants SFRH/BD/69785/2010, and SFRH/BD/85879/2012. Funding for TC was also provided through FCT under the Project UID/AGR/00115/2013 to ICAAM. Funding for PB, AU and AMR was provided by project IF/01015/2013/CP1209/CT0001 and FCT project UID/AGR/00115/2013. This work was also supported by Program Alentejo 2020, through the European Fund for Regional Development under the scope of LENTIDEV – A molecular approach to cork porosity (REF: ALT20-03-0145-FEDER-000020). These funding bodies played no role in this study’s design, collection, analysis, interpretation of data, or writing of the manuscript.
Journal Article
Carbon footprint and sustainability assessment of wood utilisation in Hungary
Forest management allows the sustained removal of significant amounts of carbon from the atmosphere. Within different activities in the forest, wood utilisation has the most significant man-made environmental impact which affects the carbon balance, which is important to know, to be able to accurately identify its role in climate change. This study aims to determine the carbon footprint of logging during utilisation based on scenario analysis in national default and theoretical assortment structures (11 additional scenarios for each forest stand) within the entire life cycle of raw wood products. Based on a common functional unit (100 m
3
of cut wood), a comparative environmental life cycle analysis (LCA) for intermediate and final cutting was performed in shortwood forestry work systems in beech (
Fagus spp.
), oak (
Quercus spp.
), spruce (
Picea spp.
), black locust (
Robinia pseudoacacia
), and hybrid poplar (
Populus x euramericana
) stands in Hungary. After obtaining the results, the present study calculated the carbon footprint order for the utilisation life cycle phases and the entire tree utilisation life cycle. The distribution of absolute carbon footprint (ACF: considered emitted CO
2
from fossil and biotic origins together) by final cutting exhibited the following order: hybrid poplar (6%)—spruce (8%)—beech (26%)—oak (27%)—black locust (33%). The ACF ranking for the whole technological life cycle (intermediate and final cutting, 400 m3 of cut wood) was hybrid poplar– spruce—oak—beech–black locust. The carbon footprint rankings of the studied stands were expanded to the national level.
Journal Article
Rhytidome- and cork-type barks of holm oak, cork oak and their hybrids highlight processes leading to cork formation
Background
The periderm is basic for land plants due to its protective role during radial growth, which is achieved by the polymers deposited in the cell walls. In most trees, like holm oak, the first periderm is frequently replaced by subsequent internal periderms yielding a heterogeneous outer bark made of a mixture of periderms and phloem tissues, known as rhytidome. Exceptionally, cork oak forms a persistent or long-lived periderm which results in a homogeneous outer bark of thick phellem cell layers known as cork. Cork oak and holm oak distribution ranges overlap to a great extent, and they often share stands, where they can hybridize and produce offspring showing a rhytidome-type bark.
Results
Here we use the outer bark of cork oak, holm oak, and their natural hybrids to analyse the chemical composition, the anatomy and the transcriptome, and further understand the mechanisms underlying periderm development. We also include a unique natural hybrid individual corresponding to a backcross with cork oak that, interestingly, shows a cork-type bark. The inclusion of hybrid samples showing rhytidome-type and cork-type barks is valuable to approach cork and rhytidome development, allowing an accurate identification of candidate genes and processes. The present study underscores that abiotic stress and cell death are enhanced in rhytidome-type barks whereas lipid metabolism and cell cycle are enriched in cork-type barks. Development-related DEGs showing the highest expression, highlight cell division, cell expansion, and cell differentiation as key processes leading to cork or rhytidome-type barks.
Conclusion
Transcriptome results, in agreement with anatomical and chemical analyses, show that rhytidome and cork-type barks are active in periderm development, and suberin and lignin deposition. Development and cell wall-related DEGs suggest that cell division and expansion are upregulated in cork-type barks whereas cell differentiation is enhanced in rhytidome-type barks.
Journal Article
Changes in the quality of marcescent and shed senescent leaves during the dormant season
Background and aims
Marcescence, the phenomenon in which plants hold their leaves after senescence, is common in nature. To date, the ecological relevance of marcescent leaves has been highlighted predominantly in arid ecosystems, where the photodegradation of recalcitrant compounds in such leaves facilitates their subsequent decomposition once shed. Marcescence, however, is widespread also in temperate ecosystems, where photodegradation is expected to be less pronounced, while other factors such as leaching or limited access of decomposers may be more important.
Methods
To provide insights into the impact of marcescence on leaf chemistry and potential consequences for decomposition and nutrient cycling in temperate ecosystems, we collected marcescent and shed senescent leaves of the tree genera Quercus L. and Fagus L. throughout two consecutive dormant seasons. We analysed these leaves for carbon and nitrogen, extracted lignin and water-extractable organic matter, and performed Fourier-transform infrared spectroscopic analyses.
Results
Our results indicate that marcescent leaves were richer in nitrogen, perhaps, due to a dominance of abiotic processes acting on these leaves (e.g., leaching of carbon), and had decreased lignin contents, likely due to photodegradation, which could subsequently release easily utilisable compounds via breakdown of lignocellulose complexes.
Conclusion
Marcescent leaves may be more bioavailable as compared to leaves directly shed after senescence, with potential consequences for nutrient and carbon cycling in temperate ecosystems.
Journal Article
Altitudinal patterns of leaf stoichiometry and nutrient resorption in Quercus variabilis in the Baotianman Mountains, China
Background Most studies focus on macronutrient of C, N and P and ignore other elements, which restrict our understanding on the strategy of plant nutrient adaption and nutrient cycling. Methods We investigated 14 element (C, N, P, S, K, Ca, Mg, Fe, Mn, Zn, Cu, Na, Al, and Ba) concentrations of green and senesced leaves in Quercus variabilis along the altitude in the Baotianman Mountains, China, and assessed their relationships with climate, soil, and plant functional traits. Results Leaf N, S and increased with, C, Ca, Na, Fe, Mn, Cu and Ba decreased with, and P, Mg, Al, Zn and N:P did not change significantly with altitude. NRE and SRE increased with, and CRE decreased with altitude (p < 0.05). Among the 14 elements, nucleic acid-protein elements (N, K, S and P) were resorbed preferentially, compare to structural (Ca, Mn, and B) and enzymatic (C, Cu, Mg and Zn) that were discriminated against, and toxic (Al and Fe) elements that were totally excluded. Conclusions Q. variabilis can synergetically regulate green leaf multielement stoichiometry and nutrient résorption in responses to environment change. Deciduous plants may have a trade-off mechanism at the end of growing season to rebalance somatic nutrients.
Journal Article
Mycorrhization of Quercus mongolica seedlings by Tuber melanosporum alters root carbon exudation and rhizosphere bacterial communities
Funding text 1 We thank Yunnan High Level Talent Introduction Plan, as well as Fei Li, Liangliang Yue, Zhongfu Zhang, Wei Chang and Rui Yan for various supports. We also appreciate Prof. Gregory Bonito (Michigan State University) for careful reading and language editing. Funding text 2 This work was supported by Kunming Institute of Botany, CAS (Y9627111K1), National Natural Science Foundation of China (31901204) and Guizhou Science and Technology Program (No. 4002, 2018).
Journal Article
A Fine-Tuning of the Plant Hormones, Polyamines and Osmolytes by Ectomycorrhizal Fungi Enhances Drought Tolerance in Pedunculate Oak
The drought sensitivity of the pedunculate oak (Quercus robur L.) poses a threat to its survival in light of climate change. Mycorrhizal fungi, which orchestrate biogeochemical cycles and particularly have an impact on the plant’s defense mechanisms and metabolism of carbon, nitrogen, and phosphorus, are among the microbes that play a significant role in the mitigation of the effects of climate change on trees. The study’s main objectives were to determine whether ectomycorrhizal (ECM) fungi alleviate the effects of drought stress in pedunculate oak and to investigate their priming properties. The effects of two levels of drought (mild and severe, corresponding to 60% and 30% of field capacity, respectively) on the biochemical response of pedunculate oak were examined in the presence and absence of ectomycorrhizal fungi. To examine whether the ectomycorrhizal fungi modulate the drought tolerance of pedunculate oak, levels of plant hormones and polyamines were quantified using UPLC-TQS and HPLC-FD techniques in addition to gas exchange measurements and the main osmolyte amounts (glycine betaine-GB and proline-PRO) which were determined spectrophotometrically. Droughts increased the accumulation of osmolytes, such as proline and glycine betaine, as well as higher polyamines (spermidine and spermine) levels and decreased putrescine levels in both, mycorrhized and non-mycorrhized oak seedlings. In addition to amplifying the response of oak to severe drought in terms of inducible proline and abscisic acid (ABA) levels, inoculation with ECM fungi significantly increased the constitutive levels of glycine betaine, spermine, and spermidine regardless of drought stress. This study found that compared to non-mycorrhized oak seedlings, unstressed ECM-inoculated oak seedlings had higher levels of salicylic (SA) and abscisic acid (ABA) but not jasmonic acid (JA), indicating a priming mechanism of ECM is conveyed via these plant hormones. According to a PCA analysis, the effect of drought was linked to the variability of parameters along the PC1 axe, such as osmolytes PRO, GB, polyamines, and plant hormones such as JA, JA-Ile, SAG, and SGE, whereas mycorrhization was more closely associated with the parameters gathered around the PC2 axe (SA, ODPA, ABA, and E). These findings highlight the beneficial function of the ectomycorrhizal fungi, in particular Scleroderma citrinum, in reducing the effects of drought stress in pedunculate oak.
Journal Article