Seasonal retranslocation in white pine (Pinus strobus L.) and white spruce (Picea glauca (Moench) Voss) was examined in response to silvicultural treatments (scarification, annual fertilization application, and annual control of competing vegetation with herbicide) that changed both environmental conditions and the growth rate of the trees. Four years after plantation establishment and initial treatment, nutrient accumulation in current-year needles of white pine and retranslocation from 1-year-old needles were increased following the vegetation control treatment, which increased resource availability (nutrients, water and light) and, hence, growth rate. Nutrient accumulation also increased in current-year white spruce needles following the same treatment, whereas retranslocation decreased in 1-year-old white spruce needles. Correlations of retranslocation (N, P and K) with growth rate (shoot biomass increment) showed a strong positive relationship for white pine and a negative relationship for white spruce. Retranslocation of K was correlated with foliar and soil K concentrations; the availability of this nutrient was also significantly reduced by vegetation control. A general theory for the control of nutrient retranslocation in conifers, which is not based exclusively on either sink strength or soil nutrient availability, is proposed. We conclude that retranslocation response is species specific and related to the potential phenotypic growth response to changing environmental conditions and to short-term imbalance in the supply versus the demand for nutrients.
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http://dx.doi.org/10.1093/treephys/15.3.141 | DOI Listing |
PLoS One
January 2025
Département des Sciences Naturelles, Institut des Sciences de la Forêt Tempérée (ISFORT), Université du Québec en Outaouais (UQO), Ripon, Canada.
Forests face an escalating threat from the increasing frequency of extreme drought events driven by climate change. To address this challenge, it is crucial to understand how widely distributed species of economic or ecological importance may respond to drought stress. In this study, we examined the transcriptome of white spruce (Picea glauca (Moench) Voss) to identify key genes and metabolic pathways involved in the species' response to water stress.
View Article and Find Full Text PDFJAMA
December 2024
Warwick Medical School, Clinical Trials Unit, University of Warwick, Coventry, United Kingdom.
Importance: For hospitalized critically ill adults with suspected sepsis, procalcitonin (PCT) and C-reactive protein (CRP) monitoring protocols can guide the duration of antibiotic therapy, but the evidence of the effect and safety of these protocols remains uncertain.
Objective: To determine whether decisions based on assessment of CRP or PCT safely results in a reduction in the duration of antibiotic therapy.
Design, Setting, And Participants: A multicenter, intervention-concealed randomized clinical trial, involving 2760 adults (≥18 years), in 41 UK National Health Service (NHS) intensive care units, requiring critical care within 24 hours of initiating intravenous antibiotics for suspected sepsis and likely to continue antibiotics for at least 72 hours.
Int J Environ Res Public Health
October 2024
Department of Public Health Sciences, University of Rochester, 265 Crittenden Boulevard, Rochester, NY 14642, USA.
Sci Total Environ
December 2024
Mistik Askwin Dendrochronology Laboratory, Department of Soil Science, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK, Canada.
Climate conditions throughout the 21st century across much of western Canada's boreal forest have been drier than normal leading to significant impacts on forest productivity and tree growth. Determining the limiting factors of radial growth in common boreal tree species under current and future conditions is crucial to reconcile how they will continue to respond to climate change. In this study, we used a network of 26 white spruce tree-ring chronologies south of its natural range as an artificially constructed trailing edge to assess climate-growth relationships and limiting factors by identifying seasonal climate relationships and using the Vaganov-Shashkin Lite (VS-Lite) model, respectively.
View Article and Find Full Text PDFFor Res (Fayettev)
December 2023
State Key Laboratory of Efficient Production of Forest Resources, National Engineering Research Center of Tree Breeding and Ecological Restoration, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China.
DNA methylation plays a crucial role in the development of somatic embryos (SEs) through the regulation of gene expression. To examine the impact of DNA methylation on gene expression during early SE development in , the demethylation reagent 5-aza-dC (5-aza-2'-deoxycytidine) was employed to modify DNA methylation regions and levels during the pre-maturation stage of somatic embryogenesis. The application of 2.
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