metabolomic-analysis-of-barley-by-gas-chromatographymass-spectrometry

Metabolomic Analysis of Barley by Gas Chromatography/Mass Spectrometry

Climate change increases drought risk to agriculture and impacts both food nutrient content and overall food security. Metabolomics is one way to observe ...

University of Idaho

Models predict that vertical gradients of foliar nitrogen (N) allocation, increasing from bottom to top of plant canopies, emerge as a plastic response to optimise N utilisation for carbon assimilation. While this mechanism has been well documented in monocultures, its relevance for mixed stands of varying species richness remains poorly understood. We used 21 naturally assembled grassland communities to analyse the gradients of N in the canopy using N allocation coefficients (K  ) estimated from the distribution of N per foliar surface area (K) and ground surface area (K). We tested whether: 1) increasing plant species richness leads to more pronounced N gradients as indicated by higher K  -values, 2) K  is a good predictor of instantaneous net ecosystem CO exchange and 3) functional diversity of leaf N concentration as estimated by Rao's Q quadratic diversity metric is a good proxy of K  . Our results show a negative (for K) or no relationship (for K) between species richness and canopy N distribution, but emphasize a link (positive relationship) between more foliar N per ground surface area in the upper layers of the canopy (i.e. under higher K) and ecosystem CO uptake. Rao's Q was not a good proxy for either K  .

Top canopy nitrogen allocation linked to increased grassland carbon uptake in stands of varying species richness.

Many scientific disciplines are currently experiencing a 'reproducibility crisis' because numerous scientific findings cannot be repeated consistently. A novel but controversial hypothesis postulates that stringent levels of environmental and biotic standardization in experimental studies reduce reproducibility by amplifying the impacts of laboratory-specific environmental factors not accounted for in study designs. A corollary to this hypothesis is that a deliberate introduction of controlled systematic variability (CSV) in experimental designs may lead to increased reproducibility. To test this hypothesis, we had 14 European laboratories run a simple microcosm experiment using grass (Brachypodium distachyon L.) monocultures and grass and legume (Medicago truncatula Gaertn.) mixtures. Each laboratory introduced environmental and genotypic CSV within and among replicated microcosms established in either growth chambers (with stringent control of environmental conditions) or glasshouses (with more variable environmental conditions). The introduction of genotypic CSV led to 18% lower among-laboratory variability in growth chambers, indicating increased reproducibility, but had no significant effect in glasshouses where reproducibility was generally lower. Environmental CSV had little effect on reproducibility. Although there are multiple causes for the 'reproducibility crisis', deliberately including genetic variability may be a simple solution for increasing the reproducibility of ecological studies performed under stringently controlled environmental conditions.

Genotypic variability enhances the reproducibility of an ecological study.

Southwest Siberia encompasses the forest-steppe and sub-taiga climatic zones and has historically been utilized for agriculture. Coinciding with predicted changes in climate for the region is the pressure of agricultural development; however, a characterization of the soil water and carbon dynamics is lacking. We assessed current soil water properties and soil organic carbon turnover in forests and grasslands for two sites that span the forest steppe and sub-taiga bioclimatic zones. Soil evaporation was 0.62 ± 0.17 mm d (mean ± standard error) in grasslands and 0.45 ± 0.08 mm d in the forests of the forest-steppe site. Evaporation at the sub-taiga site was 1.80 ± 1.70 mm d in grasslands and 0.96 ± 0.05 mm d in forest plots. Evaporation was significantly greater at the sub-taiga site than the forest-steppe site. The density of fine roots explained the soil water isotopic patterns between vegetation types and sites. We found soil organic matter turnover to be three times faster in the sub-taiga site than in the forest-steppe site. Our results show that while climate factors, in particular snow levels, between the two sites are drivers for water and carbon cycles, site level hydrology, soil characteristics, and vegetation directly interact to influence the water and carbon dynamics.

Article	Year
Top canopy nitrogen allocation linked to increased grassland carbon uptake in stands of varying species richness. Scientific reports\| PubMed ID: 28814757	2017
Genotypic variability enhances the reproducibility of an ecological study. Nature ecology & evolution\| PubMed ID: 29335575	2018
Soil evaporation and organic matter turnover in the Sub-Taiga and Forest-Steppe of southwest Siberia. Scientific reports\| PubMed ID: 30026597	2018

Zachary Kayler

Biography

JoVE Journal Publications

Other Publications