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Tree Physiology

Marek J Krasowski, Michael B Lavigne, Michael A Szuter, Jakub Olesinski, John A Kershaw, Elizabeth McGarrigle
Fine-root (≤2 mm) demographics change as forests age, but the direction and extent of change are unknown. Knowledge of the change and understanding of causes will improve predictions of climate change impacts. We used minirhizotrons at three young and three mature balsam fir (Abies balsamea (L.) Mill.) sites to measure median lifespan (MLS) for each site and for annual cohorts. We computed turnover rate from the inverse of MLS (Tinv) and calculated a second turnover rate (T) from annual mortality, annual production and previous year-end standing crop...
February 14, 2018: Tree Physiology
Adolfo Rosati, Andrea Paoletti, Raeed Al Hariri, Franco Famiani
The amount of shoot stem (i.e., woody part of the shoot) dry matter per unit shoot leaf dry matter (i.e., the shoot wood to leaf biomass ratio) has been reported to be lower in short shoots than in long ones, and this is related to the greater and earlier ability of short shoots to export carbon. This is important in fruit trees, since the greater and earlier carbon export ability of shoots with a lower wood to leaf biomass ratio improves fruit production. This ratio may vary with cultivars, training systems or plant age, but no study has previously investigated the possible effect of fruit production...
February 14, 2018: Tree Physiology
Eva Darenova, Manuel Acosta, Radek Pokorny, Marian Pavelka
This study presents results from continuous measurements of stem CO2 efflux carried out for seven experimental seasons (from May to October) in a young Norway spruce forest. The objectives of the study were to determine variability in the response of stem CO2 efflux to stem temperature over the season and to observe differences in the calculated relationship between stem temperature and CO2 efflux based on full growing season data or on data divided into periods according to stem growth rate. Temperature sensitivity of stem CO2 efflux (Q10) calculated for the established periods ranged between 1...
February 7, 2018: Tree Physiology
Angelica E Patterson, Rachel Arkebauer, Crystal Quallo, Mary A Heskel, Ximeng Li, Natalie Boelman, Kevin L Griffin
The forests of the northeastern US are globally, one of the fastest growing terrestrial carbon sinks due to historical declines in large-scale agriculture, timber harvesting and fire disturbance. However, shifting range distributions of tree species with warming air temperatures are altering forest community composition and carbon dynamics. Here, we focus on respiration, a physiological process that is strongly temperature and species dependent. We specifically examined the response of respiration (R; CO2 release) to temperature in 10 broadleaved and six conifer species, as well as the respiratory quotient (RQ; ratio of CO2 released to O2 consumed) of nine broadleaved species that co-occur in the Hudson Highlands Region of New York, USA...
February 7, 2018: Tree Physiology
Yacheng Huang, Yongjun Fang, Xiangyu Long, Linya Liu, Jia Wang, Jinheng Zhu, Yanyan Ma, Yunxia Qin, Jiyan Qi, Xinwen Hu, Chaorong Tang
Metallothioneins (MTs) as reactive oxygen species (ROS) scavengers play important roles in stress response and heavy metal homeostasis. In Hevea brasiliensis (the para rubber tree that is the source of commercial natural rubber) and in other trees, the functions of MTs are not well understood. Latex exudes when the rubber tree is tapped. The flow of latex and its regeneration can be enhanced by tapping, wounding and ethylene treatment, all of which produce ROS as a by-product. Here, we show the presence of four MT genes in H...
February 7, 2018: Tree Physiology
Junzhou Zhang, Xiaohua Gou, Neil Pederson, Fen Zhang, Haoge Niu, Shoudong Zhao, Fang Wang
Knowing more precisely the cambial phenology and wood formation dynamics of trees can lead to a better understanding on how trees react to short-term changes in environmental conditions. Such an understanding could also shed light on the physiological foundation of climate-growth interactions at a regional scale. Although it has been documented that temperature is an important factor determining the cambial phenology in cold and humid climates, there is less agreement on the driver(s) that trigger the onset and end of wood formation in cold and arid climates...
February 1, 2018: Tree Physiology
Guang-You Hao, N Michele Holbrook, Maciej A Zwieniecki, Vincent P Gutschick, Hormoz BassiriRad
Stomatal conductance (gs) generally decreases under elevated CO2 concentration (eCO2) and its sensitivity varies widely among species, yet the underlying mechanisms for these observed patterns are not totally clear. Understanding these underlying mechanisms, however, is critical for addressing problems regarding plant-environment interactions in a changing climate. We examined gs, water transport efficiency of different components along the whole-plant hydraulic system and allometric scaling in seedlings of six tree species grown under ambient and eCO2 treatments (400 and 600 ppm, respectively)...
February 1, 2018: Tree Physiology
Kuibin Meng, Yuxia Wu
Populus, a deciduous tree species of major economic and ecological value, grows across the range in which trees are distributed in the Northern Hemisphere. Patterns of DNA variation are often used to identify the evolutionary forces shaping the genotypes of distinctive species lineages. Sodium/hydrogen (Na+/H+) antiporter genes have been shown to play a central role in plant salt tolerance. Here, we analyzed DNA nucleotide polymorphisms in the Na+/H+ antiporter (NHX and SOS1) gene families across 30 different Populus species using several methods of phylogenetic analysis and functional verification...
January 31, 2018: Tree Physiology
Micah E Stevens, Keith E Woeste, Paula M Pijut
Cutting propagation plays a large role in the forestry and horticulture industries where superior genotypes need to be clonally multiplied. Integral to this process is the ability of cuttings to form adventitious roots. Recalcitrance to adventitious root development is a serious hurdle for many woody plant propagation systems including black walnut (Juglans nigra L.), an economically valuable species. The inability of black walnut to reliably form adventitious roots limits propagation of superior genotypes...
January 25, 2018: Tree Physiology
Jordi Martínez-Vilalta
No abstract text is available yet for this article.
January 24, 2018: Tree Physiology
A Ito, T Sakaue, O Fujimaru, A Iwatani, T Ikeda, D Sakamoto, T Sugiura, T Moriguchi
Mild winters influenced by global warming have increased the incidence of erratic flowering ('flowering disorder') in Japanese pear (Pyrus pyrifolia Nakai) trees in Japan. To discover how, when and what kind of disorder/damage occur in pear flower buds, we observed axillary flower buds of two cultivars, 'Kosui' (a mid-chill cultivar) and 'Niitaka' (a high-chill cultivar), grown at five locations. We focused on the phenology from autumn 2015 to spring 2016, when temperatures were higher than for average years, especially from September to January, and large fluctuations occurred due to El Niño...
January 23, 2018: Tree Physiology
Fermín Gortari, Juan José Guiamet, Corina Graciano
Rust produced by Melampsora sp. is considered one of the most relevant diseases in poplar plantations. Growth reduction in poplar plantations takes place because rust, like other pathogens, alters leaf physiology. There is not a complete evaluation of several of the physiological traits that can be affected by rust at leaf level. Therefore, the aim of this work was to evaluate, in an integrative way and in the same pathosystem, which physiological processes are affected when Populus deltoides Bartr. ex Marsh...
January 23, 2018: Tree Physiology
Hewei Zhao, Shengchang Yang, Xudong Guo, Congjiao Peng, Xiaoxuan Gu, Chuanyuan Deng, Luzhen Chen
Mangrove species have developed uniquely efficient water-use strategies in order to survive in highly saline and anaerobic environments. Herein, we estimated the stand water use of two diffuse-porous mangrove species of the same age, Sonneratia apetala Buch. Ham and Sonneratia caseolaris (L.) Engl., growing in a similar intertidal environment. Specifically, to investigate the radial patterns of axial sap flow density (Js) and understand the anatomical traits associated with them, we measured axial sap flow density in situ together with micromorphological observations...
January 16, 2018: Tree Physiology
Chandra H McAllister, Colleen E Fortier, Kate R St Onge, Bianca M Sacchi, Meaghan J Nawrot, Troy Locke, Janice E K Cooke
Mountain pine beetle (Dendroctonus ponderosae Hopkins; MPB) is an economically and ecologically important pest of pine species in western North America. Mountain pine beetles form complex multipartite relationships with microbial partners, including the ophiostomoid fungi Grosmannia clavigera (Robinson-Jeffrey and Davidson) Zipfel, de Beer and Wingfield, Ophiostoma montium (Rumbold) von Arx, Grosmannia aurea (Robinson-Jeffrey and Davidson) Zipfel, de Beer and Wingfield, Leptographium longiclavatum (Lee, Kim, and Breuil) and Leptographium terebrantis (Barras and Perry)...
January 10, 2018: Tree Physiology
Benoît Pallas, Sylvie Bluy, Jérôme Ngao, Sébastien Martinez, Anne Clément-Vidal, Jean-Jacques Kelner, Evelyne Costes
In plants, carbon source-sink relationships are assumed to affect their reproductive effort. In fruit trees, carbon source-sink relationships are likely to be involved in their fruiting behavior. In apple, a large variability in fruiting behaviors exists, from regular to biennial, which has been related to the within-tree synchronization vs desynchronization of floral induction in buds. In this study, we analyzed if carbon assimilation, availability and fluxes as well as shoot growth differ in apple genotypes with contrasted behaviors...
January 9, 2018: Tree Physiology
Peter Prislan, Katarina Cufar, Martin De Luis, Jožica Gricar
We investigated the dynamics of xylem differentiation processes and vessel characteristics in Fagus sylvatica L. to evaluate the plasticity of xylem structures under different environmental conditions. In 2008-10, analyses were performed on microcores collected weekly from two temperate sites: Menina planina (1200 m above sea level (a.s.l.)) and Panska reka (400 m a.s.l.). The duration between the onset and end of major cell differentiation steps and vessel characteristics (i.e., density, VD; mean diameter, MVD; mean area, MVA; and theoretic conductivity area, TCA) were analysed in the first and last quarters of the xylem rings, also in respect of local weather conditions (precipitation, temperature)...
January 9, 2018: Tree Physiology
Laura Fernández-Pérez, Pedro Villar-Salvador, Jordi Martínez-Vilalta, Andrei Toca, Miguel A Zavala
Drought and frosts are major determinants of plant functioning and distribution. Both stresses can cause xylem embolism and foliage damage. The objective of this study was to analyse if the distribution of six common pine species along latitudinal and altitudinal gradients in Europe is related to their interspecific differences in frost tolerance and to the physiological mechanisms underlying species-specific frost tolerance. We also evaluate if frost tolerance depends on plant water status. We studied survival to a range of freezing temperatures in 2-year-old plants and assessed the percentage loss of hydraulic conductivity (PLC) due xylem embolism formation and foliage damage determined by needle electrolyte leakage (EL) after a single frost cycle to -15 °C and over a range of predawn water potential (ψpd) values...
January 9, 2018: Tree Physiology
Claude Plassard
No abstract text is available yet for this article.
January 4, 2018: Tree Physiology
Adriano Losso, Tommaso Anfodillo, Andrea Ganthaler, Werner Kofler, Yvonne Markl, Andrea Nardini, Walter Oberhuber, Gerhard Purin, Stefan Mayr
In alpine regions, tree hydraulics are limited by low temperatures that restrict xylem growth and induce winter frost drought and freezing stress. While several studies have dealt with functional limitations, data on elevational changes in functionally relevant xylem anatomical parameters are still scarce. In wood cores of Pinus cembra L. and Picea abies (L.) Karst. trunks, harvested along five elevational transects, xylem anatomical parameters (tracheid hydraulic diameter dh, wall reinforcement (t/b)2), pit dimensions (pit aperture Da, pit membrane Dm and torus Dt diameters) and respective functional indices (torus overlap O, margo flexibility) were measured...
January 4, 2018: Tree Physiology
Catherine Preece, Gerard Farré-Armengol, Joan Llusià, Josep Peñuelas
Root exudation is an important input of carbon into soils and affects plant and soil communities, but little is known about the effect of climatic factors such as drought on exudation, and its ability to recover. We studied the impact of increasing drought on root exudation and its subsequent recovery in the Mediterranean tree species Quercus ilex L. in a greenhouse study by measuring the amount of total organic carbon in exudates. The amount of exudation per unit root area increased with drought duration and was 21% higher under the most extreme drought scenario compared with the non-droughted control...
January 3, 2018: Tree Physiology
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