Read by QxMD icon Read


Sarah Freitas Magalhães, Sofia Calvo-Rodriguez, Mário Marcos do Espírito Santo, Gerardo Arturo Sánchez Azofeifa
Vegetation indices are useful tools to remotely estimate several important parameters related to ecosystem functioning. However, improving and validating estimations for a wide range of vegetation types are necessary. In this study, we provide a methodology for the estimation of the leaf area index (LAI) in a tropical dry forest (TDF) using the light diffusion through the canopy as a function of the successional stage. For this purpose, we estimated the K coefficient, a parameter that relates the normalized difference vegetation index (NDVI) to LAI, based on photosynthetically active radiation (PAR) and solar radiation...
March 15, 2018: International Journal of Biometeorology
Heinz-Josef Koch, Kerrin Trimpler, Anna Jacobs, Nicol Stockfisch
In Europe, the framework for sugar beet ( Beta vulgaris L.) production was subject to considerable changes and for the future it is expected that sugar beet cultivation might concentrate around the sugar factories for economic reasons. Based on data from a national sugar beet farmers' survey and multi-year crop rotation trials, the effects of cropping interval (number of years in between two subsequent sugar beet crops) and of preceding crops on sugar yield were elucidated under current Central European management conditions...
2018: Frontiers in Plant Science
Sajitha Biju, Sigfredo Fuentes, Dorin Gupta
Lentil (Lens culinaris, Medik.) is an important legume crop, which often experience drought stress especially at the flowering and grain filling phenological stages. The availability of efficient and robust screening tools based on relevant non-destructive quantifiable traits would facilitate research on crop improvement for drought tolerance. The objective of this study was to evaluate the drought tolerance of 37 lentil genotypes using infrared thermal imaging (IRTI), drought tolerance parameters and multivariate data analysis...
March 8, 2018: Plant Physiology and Biochemistry: PPB
Qiong Zheng, Wenjiang Huang, Ximin Cui, Yue Shi, Linyi Liu
Yellow rust is one of the most destructive diseases for winter wheat and has led to a significant decrease in winter wheat quality and yield. Identifying and monitoring yellow rust is of great importance for guiding agricultural production over large areas. Compared with traditional crop disease discrimination methods, remote sensing technology has proven to be a useful tool for accomplishing such a task at large scale. This study explores the potential of the Sentinel-2 Multispectral Instrument (MSI), a newly launched satellite with refined spatial resolution and three red-edge bands, for discriminating between yellow rust infection severities (i...
March 15, 2018: Sensors
Chao Zhang, Jiangui Liu, Jiali Shang, Huanjie Cai
Winter wheat (Triticum aestivum L.) is a major crop in the Guanzhong Plain, China. Understanding its water status is important for irrigation planning. A few crop water indicators, such as the leaf equivalent water thickness (EWT: g cm-2 ), leaf water content (LWC: %) and canopy water content (CWC: kg m-2 ), have been estimated using remote sensing techniques for a wide range of crops, yet their suitability and utility for revealing winter wheat growth and soil moisture status have not been well studied. To bridge this knowledge gap, field-scale irrigation experiments were conducted over two consecutive years (2014 and 2015) to investigate relationships of crop water content with soil moisture and grain yield, and to assess the performance of four spectral process methods for retrieving these three crop water indicators...
March 11, 2018: Science of the Total Environment
Jose A Jimenez-Berni, David M Deery, Pablo Rozas-Larraondo, Anthony Tony G Condon, Greg J Rebetzke, Richard A James, William D Bovill, Robert T Furbank, Xavier R R Sirault
Crop improvement efforts are targeting increased above-ground biomass and radiation-use efficiency as drivers for greater yield. Early ground cover and canopy height contribute to biomass production, but manual measurements of these traits, and in particular above-ground biomass, are slow and labor-intensive, more so when made at multiple developmental stages. These constraints limit the ability to capture these data in a temporal fashion, hampering insights that could be gained from multi-dimensional data...
2018: Frontiers in Plant Science
Simonetta Rubol, Bowen Ling, Ilenia Battiato
Flow resistance caused by vegetation is a key parameter to properly assess flood management and river restoration. However, quantifying the friction factor or any of its alternative metrics, e.g. the drag coefficient, in canopies with complex geometry has proven elusive. We explore the effect of canopy morphology on vegetated channels flow structure and resistance by treating the canopy as a porous medium characterized by an effective permeability, a property that describes the ease with which water can flow through the canopy layer...
March 13, 2018: Scientific Reports
Raffaele Rani, Konrad Abramowicz, Daniel S Falster, Frank Sterck, Åke Brännström
Allocation of carbohydrates between competing organs is fundamental to plant development, growth and productivity. Carbohydrates are synthesized in mature leaves and distributed via the phloem vasculature to developing buds where they are consumed to produce new biomass. The distribution and mass-allocation processes within the plant remain poorly understood and may involve complex feedbacks between different plant functions, with implications for the emergent structure of the plant. Here, we investigate how the order in which dormant buds are flushed affects the development of tree size and reproductive output during the first 20 years of growth in full light and shaded canopy environments...
March 9, 2018: Tree Physiology
Lin Xu, Yongjun Shi, Huiyun Fang, Guomo Zhou, Xiaojun Xu, Yufeng Zhou, Jixing Tao, Biyong Ji, Jun Xu, Chong Li, Liang Chen
Subtropical forests play an important role in global carbon cycle and in mitigating climate change. Knowledge on the abiotic and biotic driving factors that affect vegetation carbon stocks in subtropical forest ecosystems is needed to take full advantage of the carbon sequestration potential. We used a large-scale database from national forest continuous inventory in Zhejiang Province, and combined the Random Forest analysis (RF) and structural equation modeling (SEM) to quantify the contribution of biotic and abiotic driving factors on vegetation carbon stocks, and to evaluate the direct and indirect effects of the main driving factors...
March 10, 2018: Science of the Total Environment
Andrew D Richardson, Koen Hufkens, Tom Milliman, Donald M Aubrecht, Min Chen, Josh M Gray, Miriam R Johnston, Trevor F Keenan, Stephen T Klosterman, Margaret Kosmala, Eli K Melaas, Mark A Friedl, Steve Frolking
Vegetation phenology controls the seasonality of many ecosystem processes, as well as numerous biosphere-atmosphere feedbacks. Phenology is also highly sensitive to climate change and variability. Here we present a series of datasets, together consisting of almost 750 years of observations, characterizing vegetation phenology in diverse ecosystems across North America. Our data are derived from conventional, visible-wavelength, automated digital camera imagery collected through the PhenoCam network. For each archived image, we extracted RGB (red, green, blue) colour channel information, with means and other statistics calculated across a region-of-interest (ROI) delineating a specific vegetation type...
March 13, 2018: Scientific Data
Lindsay D Leverett, George F Schieder Iv, Kathleen Donohue
PREMISE OF THE STUDY: Phenology, the seasonal timing of development, can alter biotic interactions. Emergence from dormant or quiescent stages often occurs earlier when neighbors are present, which may reduce the neighbors' competitive effects. Delayed emergence in response to neighbors also has been observed, but the potential benefits of such delays are unclear. Further, emergence time may respond to neighbors experienced by parents, which may predict future competition in offspring...
January 2018: American Journal of Botany
Marcel Fuchs, Cecilia Stanghellini
Current research seeking to relate between ambient water vapor deficit (D) and foliage conductance (gF ) derives a canopy conductance (gW ) from measured transpiration by inverting the coupled transpiration model to yield gW  = m - n ln(D) where m and n are fitting parameters. In contrast, this paper demonstrates that the relation between coupled gW and D is gW  = AP/D + B, where P is the barometric pressure, A is the radiative term, and B is the convective term coefficient of the Penman-Monteith equation...
March 12, 2018: International Journal of Biometeorology
Tengfei Yu, Qi Feng, Jianhua Si, Patrick J Mitchell, Michael A Forster, Xiaoyou Zhang, Chunyan Zhao
During the night, plant water loss can occur either through the roots, as hydraulic redistribution (HR), or through the leaves via the stoma, as nocturnal transpiration ( E n ), which was methodologically difficult to separate from stem refilling ( R e ). While HR and E n have been reported across a range of species, ecosystem, and climate zone, there is little understanding on the interactions between E n and/or R e and HR. As water movement at night occurs via gradients of water potential, it is expected that during periods of high atmospheric vapor pressure deficit (VPD), water loss via E n will override water loss via HR...
March 2018: Ecology and Evolution
Amanda J Zellmer
Gene flow has historically been thought to constrain local adaptation; yet, recent research suggests that populations can diverge despite exchanging genes. Here I use a common garden experiment to assess the combined effects of gene flow and natural selection on morphological variation of 16 wood frog ( Rana sylvatica ) populations, a species known to experience divergent selection pressures in open- and closed-canopy ponds across relatively small geographic scales. Wood frog tadpoles from different ponds showed significant morphological variation associated with canopy type with a trade-off between tail length and body depth consistent with previous research...
March 2018: Ecology and Evolution
Erika Buscardo, József Geml, Steven K Schmidt, Helena Freitas, Hillândia Brandão da Cunha, Laszlo Nagy
Most tropical evergreen rain forests are characterised by varying degrees of precipitation seasonality that influence plant phenology and litterfall dynamics. Soil microbes are sensitive to soil water:air ratio and to nutrient availability. We studied if within-year seasonality in precipitation and litterfall-derived nutrient input resulted in predictable seasonal variation in soil bacterial diversity/microbial functional groups in an Amazonian forest. We characterised the spatio-temporal dynamics of microbial communities from the plot to the stand scales and related them to precipitation seasonality and spatial variability in soil characteristics...
March 12, 2018: Scientific Reports
Victoria Moriconi, Melanie Binkert, María Cecilia Costigliolo Rojas, Romina Sellaro, Roman Ulm, Jorge Jose Casal
Sunflecks, transient patches of light that penetrate through gaps in the canopy and transiently interrupt shade, are eco-physiologically and agriculturally important sources of energy for carbon gain, but our molecular understanding of how plant organs perceive and respond to sunflecks remains limited. The UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8) is a recent addition to the list of plant photo-sensory receptors and, we have made considerable advances in our understanding of the physiology and molecular mechanisms of action of UVR8 and its signalling pathway...
March 12, 2018: Plant Physiology
Mónica Herrero-Huerta, Roderik Lindenbergh, Wolfgang Gard
Plant leaf movement is induced by some combination of different external and internal stimuli. Detailed geometric characterization of such movement is expected to improve understanding of these mechanisms. A metric high-quality, non-invasive and innovative sensor system to analyze plant movement is Terrestrial LiDAR (TLiDAR). This technique has an active sensor and is, therefore, independent of light conditions, able to obtain accurate high spatial and temporal resolution point clouds. In this study, a movement parameterization approach of leaf plants based on TLiDAR is introduced...
2018: Frontiers in Plant Science
Morgan E Furze, Susan Trumbore, Henrik Hartmann
For trees to survive, they must allocate resources between sources and sinks to maintain proper function. The vertical transport pathway in tree stems is essential for carbohydrates and other solutes to move between the canopy and the root system. To date, research and models emphasize the role of tree stems as 'express' sugar highways. However, recent investigations using isotopic markers suggest that there is considerable storage and exchange of phloem-transported sugars with older carbon (C) reserves within the stem...
March 6, 2018: Current Opinion in Plant Biology
Xinyou Yin, Paul C Struik
Extra ATP required in C4 photosynthesis for the CO2 -concentrating mechanism probably comes from cyclic electron transport (CET). As metabolic ATP : NADPH requirements in mesophyll (M) and bundle-sheath (BS) cells differ among C4 subtypes, the subtypes may differ in the extent to which CET operates in these cells. We present an analytical model for cell-type-specific CET and linear electron transport. Modelled NADPH and ATP production were compared with requirements. For malic-enzyme (ME) subtypes, c. 50% of electron flux is CET, occurring predominantly in BS cells for standard NADP-ME species, but in a ratio of c...
March 9, 2018: New Phytologist
Aaron Teets, Shawn Fraver, Aaron R Weiskittel, David Y Hollinger
A range of environmental factors regulate tree growth; however, climate is generally thought to most strongly influence year-to-year variability in growth. Numerous dendrochronological (tree-ring) studies have identified climate factors that influence year-to-year variability in growth for given tree species and location. However, traditional dendrochronology methods have limitations that prevent them from adequately assessing stand-level (as opposed to species-level) growth. We argue that stand-level growth analyses provide a more meaningful assessment of forest response to climate fluctuations, as well as the management options that may be employed to sustain forest productivity...
March 9, 2018: Global Change Biology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"