Search results for " Botany"
showing 10 items of 1545 documents
Collecting and preserving plant DNA for huanglongbing diagnosis in citrus samples from China
2016
Accurate and sensitive detection of Citrus Huanglongbing associated ‘Ca. Liberibacter’species, not currently reported in the European and Mediterranean area, is an imperative need to define certification programs, to prevent introduction of the bacteria and/or their vectors in the unaffected areas, and to delineate efficient management strategies in those areas where the disease has spread. In this study, we compared different citrus sample preparation procedures for PCR based detection methods of ‘Candidatus Liberibacter asiaticus’, in order to find out the best a way to transport and preserve samples of Shatangju mandarin and fingered citron obtained during a survey in citrus orchards in …
Benefits for nurse and facilitated plants emerge when interactions are considered along the entire life-span
2019
The structure of plant communities is often influenced by facilitative interactions where ‘facilitated’ plants benefit from growing associated with ‘nurse’ plants. Facilitation has been mostly studied from the facilitated plant's perspective, and bidirectional effects between nurse and facilitated plants have received less attention. We hypothesized that reciprocal benefits in plant-plant interactions may emerge when interactions are considered along the life-span of the plants involved. Over one spring, we selected five species with similar life-form and growth strategy, and using a full factorial design, we compared different fitness components along the plants’ life-span (seedling establ…
« On-the-go » multispectral imaging system to characterize the development of vineyard foliage
2015
International audience; In Precision Viticulture, multispectral imaging systems are currently used in remote sensing for vineyard vigor characterization but few are employed in proximal sensing. This work presents the potential of a proximal multispectral imaging system mounted on a track-laying tractor equipped with a Greenseeker RT-100 to provide an NDVI index. The camera acquired visible and near-infrared images which were calibrated in reflectance. Vegetation indices were computed and compared to Greenseeker data. From two of the resulting datasets, a spatio-temporal study of foliage description through both optical systems is presented. This first study assessed the proximal imagery re…
Carbon sequestration potential of Italian orchards and vineyards
2017
From 2004 to 2012 carbon (C) fluxes between the soil-vegetation system and the atmosphere in apple, grape, olive and orange orchards planted in different Italian regions were measured. Above-ground net primary productivity (ANPP) ranged from 4 (olive) to 9 (apple) Mg C ha-1. Alley grass contribution to total ANPP significantly varied among the systems, reaching a maximum of 60% in vineyards. The harvest index ranged from 46% for apple, to 58% for orange, 60% for grape and 41% for olive, while abscised leaves accounted for 30% of ANPP, on average. Soil respiration fluxes ranged from 6 (orange) to 10 (grape) Mg C ha-1. Results indicate the potential of these fruit crop to sequester atmospheri…
Patterns of drought tolerance in major European temperate forest trees: climatic drivers and levels of variability
2013
The future performance of native tree species under climate change conditions is frequently discussed, since increasingly severe and more frequent drought events are expected to become a major risk for forest ecosystems. To improve our understanding of the drought tolerance of the three common European temperate forest tree species Norway spruce, silver fir and common beech, we tested the influence of climate and tree-specific traits on the inter and intrasite variability in drought responses of these species. Basal area increment data from a large tree-ring network in Southern Germany and Alpine Austria along a climatic cline from warm-dry to cool-wet conditions were used to calculate indi…
Temporal variations in microclimate cooling induced by urban trees in Mainz, Germany
2016
Abstract Global warming is likely to increase the frequency and magnitude of heat waves. As the urban geometry and material amplifies warming, city dwellers will face an intensification of heat-induced health problems and mortality. Although increased vegetation cover is frequently used in urban planning to mitigate excessive heat, temporal variations, as well as the influence of synoptic weather conditions and surrounding urban geometry on the vegetation cooling effect, are still unclear. In this study, we monitored the transpiration-induced cooling from trees over two summers in five urban settings characterized by varying levels of greenness and urban geometry in the city of Mainz (Germa…
Plasticity of response of tree-ring width of Scots pine provenances to weather extremes in Latvia
2019
Abstract Climatic changes and weather extremes are causing shifts in distribution of tree species, affecting productivity of forests. With the northwards advance of deciduous species in Northern Europe, Scots pine (Pinus sylvestris L.) is predicted to decrease survival and productivity. Nevertheless, Scots pine have adapted to diverse environments, hence selection among its populations could be applied to sustain productivity of stands under changing climate. In this study, sensitivity of tree-ring width of Eastern European provenances of Scots pine differing by field performance (Dippoldiswalde, Eibenstock, Rytel, Gustrow, and Kalsnava) to weather extremes in three trials in Latvia (hemibo…
Ecological and climatological signals in tree-ring width and density chronologies along a latitudinal boreal transect
2016
ABSTRACTShifts in the climate sensitivity of trees throughout the twentieth century might indicate climate change effects in the boreal forest ecosystem. We here evaluated such potential changes by analyzing six tree-ring width (TRW) and maximum latewood density (MXD) chronologies from northern, central and southern boreal forests in Finland (60°N–69°N). Besides latitudinal effects, differing micro-sites (lakeshore and inland) were considered to evaluate the influence of ground water access on twentieth-century tree-ring formation and climate sensitivity. Overall, the boreal MXD chronologies appeared less affected by micro-site conditions compared to the TRW chronologies. Along the boreal t…
Climate sensitivity of high- and low-elevation Larix decidua MXD chronologies from the Tatra Mountains
2020
Abstract Maximum latewood density (MXD) measurements from high-elevation/-latitude sites are an important proxy for summer temperature reconstructions. Here, we present 201 MXD series from living larch (Larix decidua Mill.) trees that were growing at around 850 and 1450 m a.s.l. in the Slovakian Tatra Mountains, together with 56 MXD series from historical timbers of the same species and region. We explore the climate signal at the high- and low-elevation sites and assess the effects of varying temperature and precipitation regimes on MXD formation. Ranging from spring temperature to summer precipitation, the elevation-specific climate sensitivity suggests that the MXD measurements from livi…
Understanding the uncertainty in global forest carbon turnover
2020
Abstract. The length of time that carbon remains in forest biomass is one of the largest uncertainties in the global carbon cycle, with both recent historical baselines and future responses to environmental change poorly constrained by available observations. In the absence of large-scale observations, models used for global assessments tend to fall back on simplified assumptions of the turnover rates of biomass and soil carbon pools. In this study, the biomass carbon turnover times calculated by an ensemble of contemporary terrestrial biosphere models (TBMs) are analysed to assess their current capability to accurately estimate biomass carbon turnover times in forests and how these times a…