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Tree Physiology

Martin Felhofer, Batirtze Prats-Mateu, Peter Bock, Notburga Gierlinger
The transition from the living water-transporting sapwood to heartwood involves in many tree species impregnation with extractives. These differ in amount and composition, and enhance resistance against bacteria, insects or fungi. To understand the synthesis, transport and impregnation processes new insights into the biochemical processes are needed by in-situ methods. Here we show the extractive distribution in pine (Pinus sylvestris) microsections with a high lateral resolution sampled in a non-destructive manner using Confocal Raman Microscopy...
July 10, 2018: Tree Physiology
Débora di Francescantonio, Mariana Villagra, Guillermo Goldstein, Paula I Campanello
Tree physiological processes are affected not only by environmental conditions, but also by phenological leaf stages. During foliar expansion, rapid changes occur, such as the activation of metabolic processes that encompass a hydraulic link between xylem and phloem pathways at a whole-tree level. Daily and seasonal changes in stem diameter may reveal different temporal dynamics of water use and recharge in tree reservoirs. Foliar phenological patterns were studied in relation to stem dimensional changes in 10 canopy tree species with different phenological patterns (three deciduous, three brevideciduous and four evergreen species)...
July 9, 2018: Tree Physiology
R M Hillabrand, V J Lieffers, E H Hogg, E Martínez-Sancho, A Menzel, U G Hacke
The study of tree rings can reveal long-term records of a tree's response to the environment. This dendroecological approach, when supplemented with finer-scale observations of the xylem anatomy, can provide novel information about a tree's year-to-year anatomical and hydraulic adjustments. Here we use this method in aspen (Populus tremuloides Michx.) to identify xylem response to drought and insect defoliation. Surprisingly, we found that precipitation influenced vessel diameter mostly in the trees' youth, while this correlation was less pronounced at maturity...
July 3, 2018: Tree Physiology
Antoine Gautier, Sarah J Cookson, Cyril Hevin, Philippe Vivin, Virginie Lauvergeat, Alain Mollier
Crop productivity is limited by phosphorus (P) and this will probably increase in the future. Rootstocks offer a means to increase the sustainability and nutrient efficiency of agriculture. It is known that rootstocks alter petiole P concentrations in grapevine. The objective of this work was to determine which functional processes are involved in genotype-specific differences in scion P content by quantifying P uptake, P remobilization from the reserves in the cutting and P allocation within the plant in three grapevine genotypes...
July 3, 2018: Tree Physiology
Francesco Petruzzellis, Andrea Nardini, Tadeja Savi, Vanessa Tonet, Miris Castello, Giovanni Bacaro
Invasion of natural habitats by alien trees is a threat to forest conservation. Our understanding of fundamental ecophysiological mechanisms promoting plant invasions is still limited, and hydraulic and water relation traits have been only seldom included in studies comparing native and invasive trees. We compared several leaf and wood functional and mechanistic traits in co-occurring Ailanthus altissima (Mill.) Swingle (Aa) and Fraxinus ornus L. (Fo). Aa is one of the most invasive woody species in Europe and North America, currently outcompeting several native trees including Fo...
July 3, 2018: Tree Physiology
Anson Call, Samuel B St Clair
Timing of herbivory or selection of specific plant tissues (mode of herbivory) by different ungulate herbivore species are likely to have important influences on plant defense strategies. In this study, we devised two different modes of simulated herbivory, representing a selective ungulate feeding strategy (defoliation: leaf tissue removal only) and a bulk feeding strategy (clipping: leaves, twigs and meristems taken together). We applied these contrasting herbivory treatments to juvenile aspen suckers (Populus tremuloides Michx...
July 3, 2018: Tree Physiology
Chaofeng Ma, Yinghao Chen, Shen Ding, Ziliang Li, Wen-Guang Shi, Yi Zhang, Zhi-Bin Luo
Sulfur (S) can modulate plant responses to toxic heavy metals, but the underlying physiological and transcriptional regulation mechanisms remain largely unknown. To investigate the effects of S supply on lead (Pb)-induced toxicity in poplars, Populus deltoides monilifera (Aiton) Eckenw. saplings were exposed to 0 or 50 μM Pb together with one of the three S concentrations (0 (low S), 100 (moderate S) or 1500 (high S) μM Na2SO4). Populus deltoides roots absorbed Pb and it was partially translocated to the aerial organs, thereby decreasing the CO2 assimilation rate and leaf growth...
June 25, 2018: Tree Physiology
Bin Liu, Eve Kaurilind, Yifan Jiang, Ülo Niinemets
Methyl salicylate (MeSA) is a long-distance signal transduction chemical that plays an important role in plant responses to abiotic stress and herbivore and pathogen attacks. However, it is unclear how photosynthesis and elicitation of plant volatile organic compounds (VOC) from different metabolic pathways respond to the dose of MeSA. We applied different MeSA concentrations (0-50 mM) to study how exogenous MeSA alters VOC profiles of silver birch (Betula pendula Roth) leaves from application through recovery (0...
June 20, 2018: Tree Physiology
Masako Dannoura, Daniel Epron, Dorine Desalme, Catherine Massonnet, Shoko Tsuji, Caroline Plain, Pierrick Priault, Dominique Gérant
Phloem failure has recently been recognized as one of the mechanisms causing tree mortality under drought, though direct evidence is still lacking. We combined 13C pulse-labelling of 8-year-old beech trees (Fagus sylvatica L.) growing outdoors in a nursery with an anatomical study of the phloem tissue in their stems to examine how drought alters carbon transport and phloem transport capacity. For the six trees under drought, predawn leaf water potential ranged from -0.7 to -2.4 MPa, compared with an average of -0...
June 20, 2018: Tree Physiology
Xiaohong Liu, Liangju Zhao, Steven Voelker, Guobao Xu, Xiaomin Zeng, Xuanwen Zhang, Lingnan Zhang, Weizhen Sun, Qiuliang Zhang, Guoju Wu, Xiaoqin Li
Tree-ring δ13C and δ18O of dominant Dahurian larch and Mongolia pine in the permafrost region of the northern Great Higgnan Mountains, China were used to elucidate species-specific ecophysiological responses to warming temperatures and increasing CO2 over the past century. Larch and pine stable carbon discrimination (Δ13C) 13C and δ18O in tree rings both showed synchronous changes during the investigated period (1901-2010), but with species-specific isotopic responses to atmospheric enriched CO2 and warming...
June 15, 2018: Tree Physiology
Royd Vinya, Yadvinder Malhi, Nick D Brown, Joshua B Fisher, Timothy Brodribb, Luiz E O C Aragão
Water availability has frequently been linked to seasonal leaf display in seasonally dry ecosystems, but there have been few ecohydrological investigations of this link. Miombo woodland is a dominant seasonally dry tropical forest ecosystem type in southern Africa; however, there are few data on the relationship between seasonal dynamics in plant-water relations and patterns of leaf display for Miombo woodland. Here we investigate this relationship among nine key Miombo woodland tree species differing in drought tolerance ability and leaf phenology...
June 15, 2018: Tree Physiology
Eri Nabeshima, Takeshi Nakatsuka, Akira Kagawa, Tsutom Hiura, Ryo Funada
Leaf photosynthetic and post-photosynthetic processes modulate the isotope ratios of tree-ring cellulose. Post-photosynthetic processes, such as the remobilization of stored starch in early spring, are important to understanding the mechanisms of xylem formation in tree stems; however, untangling the isotope ratio signals of photosynthetic and post-photosynthetic processes imprinted on tree rings is difficult. Portions of carbon-bound hydrogen and oxygen atoms are exchanged with medium water during post-photosynthetic processes...
June 15, 2018: Tree Physiology
María Belén Pascual, Juan Jesús Molina-Rueda, Francisco M Cánovas, Fernando Gallardo
Cytosolic NADP+-isocitrate dehydrogenase (ICDH) is one of the major enzymes involved in the production of 2-oxoglutarate for amino acid biosynthesis in plants. In most plants studied, ICDH is encoded by either one gene or a small gene family, and the protein sequence has been highly conserved during evolution, suggesting it plays different and essential roles in metabolism and differentiation. To elucidate the role of ICDH in hybrid poplar (Populus tremula x P. alba), transgenic plants overexpressing the Pinus pinaster gene were generated...
June 15, 2018: Tree Physiology
Angela Luisa Prendin, Stefan Mayr, Barbara Beikircher, Georg von Arx, Giai Petit
As a tree grows taller, the increase in gravitational pressure and path length resistance results in lower water potentials at a given flow rate and higher carbon construction costs to transport a given amount of water to the leaves. We investigated how hydraulic safety and efficiency are coordinated under the constraints of higher cavitation risks and higher carbon construction costs with increasing tree height. We combined measurements of xylem tracheid anatomical traits with the vulnerability to drought-induced embolism and hydraulic conductivity of the apical shoots of 2- to 37-m tall Picea abies trees growing at two sites in the Dolomites (Italian Eastern Alps)...
June 15, 2018: Tree Physiology
Enrica Zalloni, Giovanna Battipaglia, Paolo Cherubini, Matthias Saurer, Veronica De Micco
Mixed forests of Quercus ilex L. and Pinus pinea L. are widely found throughout the Mediterranean Basin, being representative of two co-existing functional types: evergreen-sclerophyllous drought-resistant species and Mediterranean-adapted drought-avoidant conifers. Their contrasting physiological strategies to cope with water deficit influence all the processes regulating their growth such as wood formation, leading to peculiar tree-ring anatomical features such as intra-annual density fluctuations (IADFs)...
June 15, 2018: Tree Physiology
Zhi-Jun Shen, Juan Chen, Kabir Ghoto, Wen-Jun Hu, Gui-Feng Gao, Mei-Rong Luo, Zan Li, Martin Simon, Xue-Yi Zhu, Hai-Lei Zheng
Avicennia marina (Forsk.) Vierh is one of the most salt-tolerant mangrove species. Our previous study revealed that nitric oxide (NO) enhanced the salt tolerance of A. marina by promoting salt secretion and Na+ sequestration under salt stress. However, little is known about the regulation of NO on proteomic profiling for this mangrove species. In this study, we used sodium nitroprusside (SNP), an NO donor, to investigate the regulatory mechanism of NO on salt tolerance of A. marina according to physiological and proteomic aspects...
June 15, 2018: Tree Physiology
Jian-Ping An, Xiu-Hong An, Ji-Fang Yao, Xiao-Na Wang, Chun-Xiang You, Xiao-Fei Wang, Yu-Jin Hao
MdMYB9 is a positive regulator in the biosynthesis of anthocyanin and proanthocyanidin in apple. However, its posttranslational regulation is unclear. Here, we demonstrated that the BTB protein MdBT2 had a negative role in the biosynthesis of anthocyanin and proanthocyanidin. MdBT2 interacted with MdMYB9 and negatively regulated the abundance of MdMYB9 protein through the 26S proteasome system. The degradation of MdMYB9 by MdBT2 reduced the expression of MdMYB9-mediated anthocyanin and proanthocyanidin-related genes and reduced the accumulation of anthocyanin and proanthocyanidin, which functioned in an MdCUL3-independent pathway...
June 12, 2018: Tree Physiology
Weibin Li, Henrik Hartmann, Henry D Adams, Hongxia Zhang, Changjie Jin, Chuanyan Zhao, Dexin Guan, Anzhi Wang, Fenghui Yuan, Jiabing Wu
Non-structural carbohydrates (NSC) play a central role in plant functioning as energy carriers and building blocks for primary and secondary metabolism. Many studies have investigated how environmental and anthropogenic changes, like increasingly frequent and severe drought episodes, elevated CO2 and atmospheric nitrogen (N) deposition, influence NSC concentrations in individual trees. However, this wealth of data has not been analyzed yet to identify general trends using a common statistical framework. A thorough understanding of tree responses to global change is required for making realistic predictions of vegetation dynamics...
June 11, 2018: Tree Physiology
Thorsten Knipfer, Felipe H Barrios-Masias, Italo F Cuneo, Martin Bouda, Caetano P Albuquerque, Craig R Brodersen, Daniel A Kluepfel, Andrew J McElrone
A germplasm collection containing varied Juglans genotypes holds potential to improve drought resistance of plant materials for commercial production. We used X-ray computed microtomography to evaluate stem xylem embolism susceptibility/repair in relation to vessel anatomical features (size, arrangement, connectivity and pit characteristics) in 2-year-old saplings of three Juglans species. In vivo analysis revealed interspecific variations in embolism susceptibility among Juglans microcarpa, J. hindsii (both native to arid habitats) and J...
May 30, 2018: Tree Physiology
Xiaoyu Han, Robert Turgeon, Alexander Schulz, Johannes Liesche
Most conifer species have needle-shaped leaves that are only a few centimeters long. In general, variation in leaf size has been associated with environmental factors, such as cold or drought stress. However, it has recently been proposed that sugar export efficiency is the limiting factor for conifer needle length, based on the results obtained using a mathematical model of phloem transport. Here, phloem transport rates in long conifer needles were experimentally determined to test if the mathematical model accurately represents phloem transport...
May 30, 2018: Tree Physiology
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