scholarly journals Physiological and climate controls on foliar mercury uptake by European tree species

2021 ◽  
Author(s):  
Lena Wohlgemuth ◽  
Pasi Rautio ◽  
Bernd Ahrends ◽  
Alexander Russ ◽  
Lars Vesterdal ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Tree Species ◽  
Physiological Activity ◽  
Growing Season ◽  
Relevant Parameter ◽  
Uptake Rates ◽  
Mercury Uptake

Abstract. Despite the importance of vegetation uptake of atmospheric gaseous elemental mercury (Hg(0)) within the global Hg cycle, little knowledge exists on the physiological, climatic and geographic factors controlling stomatal uptake of atmospheric Hg(0) by tree foliage. We investigate controls on foliar stomatal Hg(0) uptake by combining Hg measurements of 3,569 foliage samples across Europe with data on tree species traits and environmental conditions. To account for foliar Hg accumulation over time, we normalized foliar Hg concentration over the foliar life period from the simulated start of the growing season to sample harvest. The most relevant parameter impacting daily foliar stomatal Hg uptake was tree functional group (deciduous versus coniferous trees). On average, we measured 3.2 times higher daily foliar stomatal Hg uptake rates in deciduous leaves than in coniferous needles of the same age. Across tree species, for foliage of beech and fir, and at two out of three forest plots with more than 20 samples, we found a significant (p < 0.001) increase in foliar Hg values with respective leaf nitrogen concentrations. We therefore suggest, that foliar stomatal Hg uptake is controlled by tree functional traits with uptake rates increasing from low to high nutrient content representing low to high physiological activity. For pine and spruce needles, we detected a significant linear decrease of daily foliar stomatal Hg uptake with the proportion of time, during which vapor pressure deficit (VPD) exceeded the species-specific threshold values of 1.2 kPa and 3 kPa, respectively. The proportion of time within the growing season, during which surface soil water content (ERA5-Land) in the region of forest plots was low correlated negatively with corresponding foliar Hg uptake rates of beech and pine. These findings suggest that stomatal uptake of atmospheric Hg(0) is inhibited under high VPD conditions and/or low soil water content due the regulation of stomatal conductance to reduce water loss under dry conditions. We therefore propose, that foliar Hg measurements bear the potential to serve as proxy for stomatal conductance. Other parameters associated with forest sampling sites (latitude and altitude), sampled trees (average age and diameter at breast height) or regional satellite observation-based transpiration product (GLEAM) did not significantly correlate with daily foliar Hg uptake rates. We conclude that tree physiological activity and stomatal response to VPD and soil water content should be implemented in a stomatal Hg model, to assess future Hg cycling under different anthropogenic emission scenarios and global warming.

Soil water content and stomatal conductance in a mature peach orchard as influenced by various irrigation regimes

1991 ◽  
Vol 71 (2) ◽  
pp. 253-258 ◽  
Author(s):  
C. S. Tan ◽  
R. E. C. Layne
Keyword(s):  
Stomatal Conductance ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Prunus Persica ◽  
Growing Season ◽  
Plant Water Stress ◽  
Rooting Zone ◽  
Neutron Probe ◽  
Peach Orchard

Available soil water (ASW) in the rooting zone of mature peach (Prunus persica (L.) Batsch 'Harken/Siberian C.') trees was determined with a neutron probe at incremental depths down to 240 cm between 1979 and 1982. The trees were either not irrigated (I0) or irrigated at a frequency necessary to prevent ASW from falling below 25% (I25) or 50% (I50) in the top 30 cm of soil. Water content in the top 120 cm from May to September for I0 plots was about 37 mm less than I25 plots and 73 mm less than I50 plots. Nonirrigated plots (I0) had the lowest ASW (< 30%) in the soil profile to a depth of 240 cm from mid-growing season onwards. By contrast, irrigated plots (I50) had high ASW (100%) at and below the 100-cm depth during the whole growing season. Leaf stomatal conductance was significantly lower for non-irrigated trees indicating that they were the most severely stressed. The severity of plant water stress increased with decreasing frequency of irrigation as indicated by reduced stomatal conductance. Key words: Prunus persica, available soil water, stomatal conductance

scholarly journals Relationship between Very Fine Root Distribution and Soil Water Content in Pre- and Post-Harvest Areas of Two Coniferous Tree Species

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1227
Author(s):  
Moein Farahnak ◽  
Keiji Mitsuyasu ◽  
Takuo Hishi ◽  
Ayumi Katayama ◽  
Masaaki Chiwa ◽  
...  
Keyword(s):  
Water Content ◽  
Root System ◽  
Soil Water ◽  
Soil Water Content ◽  
Tree Species ◽  
Fine Roots ◽  
Fine Root ◽  
Soil Depth ◽  
Tree Cutting ◽  
Coniferous Tree Species

Tree root system development alters forest soil properties, and differences in root diameter frequency and root length per soil volume reflect differences in root system function. In this study, the relationship between vertical distribution of very fine root and soil water content was investigated in intact tree and cut tree areas. The vertical distribution of root density with different diameter classes (very fine <0.5 mm and fine 0.5–2.0 mm) and soil water content were examined along a slope with two coniferous tree species, Cryptomeria japonica (L.f.) D. Don and Chamaecyparis obtusa (Siebold et Zucc.) Endl. The root biomass and length density of very fine roots at soil depth of 0–5 cm were higher in the Ch. obtusa intact tree plot than in the Cr. japonica intact plot. Tree cutting caused a reduction in the biomass and length of very fine roots at 0–5 cm soil depth, and an increment in soil water content at 5–30 cm soil depth of the Ch. obtusa cut tree plot one year after cutting. However, very fine root density of the Cr. japonica intact tree plot was quite low and the soil water content in post-harvest areas did not change. The increase in soil water content at 5–30 cm soil depth of the Ch. obtusa cut tree plot could be caused by the decrease in very fine roots at 0–5 cm soil depth. These results suggest that the distribution of soil water content was changed after tree cutting of Ch. obtusa by the channels generated by the decay of very fine roots. It was also shown that differences in root system characteristics among different tree species affect soil water properties after cutting.

scholarly journals Statistical analysis of soil water content differences after biochar application andits repeated application during 2020 growing season

2021 ◽  
Vol 22 (2) ◽  
pp. 320-325
Author(s):  
Justína Vitková ◽  
Peter šurda ◽  
Peter Rončák ◽  
Natália Botková ◽  
Anton Zvala
Keyword(s):  
Statistical Analysis ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Growing Season ◽  
Repeated Application

scholarly journals A bottom-up quantification of foliar mercury uptake fluxes across Europe

2020 ◽  
Vol 17 (24) ◽  
pp. 6441-6456 ◽  
Author(s):  
Lena Wohlgemuth ◽  
Stefan Osterwalder ◽  
Carl Joseph ◽  
Ansgar Kahmen ◽  
Günter Hoch ◽  
...  
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Growing Season ◽  
Deposition Flux ◽  
Foliar Uptake ◽  
Bottom Up ◽  
Needle Age ◽  
Uptake Rates ◽  
Mercury Uptake ◽  
Species Specific

Abstract. The exchange of gaseous elemental mercury, Hg(0), between the atmosphere and terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. Emerging evidence suggests foliar uptake of atmospheric Hg(0) to be a major deposition pathway to terrestrial surfaces. Here, we present a bottom-up approach to calculate Hg(0) uptake fluxes to aboveground foliage by combining foliar Hg uptake rates normalized to leaf area with species-specific leaf area indices. This bottom-up approach incorporates systematic variations in crown height and needle age. We analyzed Hg content in 583 foliage samples from six tree species at 10 European forested research sites along a latitudinal gradient from Switzerland to northern Finland over the course of the 2018 growing season. Foliar Hg concentrations increased over time in all six tree species at all sites. We found that foliar Hg uptake rates normalized to leaf area were highest at the top of the tree crown. Foliar Hg uptake rates decreased with needle age of multiyear-old conifers (spruce and pine). Average species-specific foliar Hg uptake fluxes during the 2018 growing season were 18 ± 3 µg Hg m−2 for beech, 26 ± 5 µg Hg m−2 for oak, 4 ± 1 µg Hg m−2 for pine and 11 ± 1 µg Hg m−2 for spruce. For comparison, the average Hg(II) wet deposition flux measured at 5 of the 10 research sites during the same period was 2.3 ± 0.3 µg Hg m−2, which was 4 times lower than the site-averaged foliar uptake flux of 10 ± 3 µg Hg m−2. Scaling up site-specific foliar uptake rates to the forested area of Europe resulted in a total foliar Hg uptake flux of approximately 20 ± 3 Mg during the 2018 growing season. Considering that the same flux applies to the global land area of temperate forests, we estimate a foliar Hg uptake flux of 108 ± 18 Mg. Our data indicate that foliar Hg uptake is a major deposition pathway to terrestrial surfaces in Europe. The bottom-up approach provides a promising method to quantify foliar Hg uptake fluxes on an ecosystem scale.

scholarly journals Effects of constantly high soil water content on vegetative growth and grape quality in Japan with high rainfall during grapevine growing season

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Yuta Kobayashi ◽  
Tetsunan Yamamoto ◽  
Hironori Ikeda ◽  
Ryuzo Sugihara ◽  
Hiroki Kaihori ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Vegetative Growth ◽  
Growing Season ◽  
Experimental Plot ◽  
Growing Seasons ◽  
High Soil ◽  
Berry Quality ◽  
Vineyard Soil

AbstractExcess water in vineyard soils during grapevine growing season is expected to become a critical issue in Japan. The objective of this study was to investigate the effects of constantly high soil water content which was controlled at constantly more than 20% water content in soil on vegetative growth and berry quality of Cabernet Sauvignon over a 3-year growing season. A wireless sensor networking system for real-time monitoring of soil moisture was used to check that the experimental plot had constantly more than 20% water content in soil. Véraison in the experimental plot controlled at constantly high soil water content started 10 days, 4 days and 1 day later than that in the non-irrigated experimental plot in the 2017, 2018 and 2019 growing seasons, respectively. The constantly high soil water content had no notable effects on berry quality, such as berry characteristics and berry composition, at harvest compared with the non-irrigated experimental plot, although there was a certain tendency that constantly high soil water content decreased anthocyanin contents in berry skins compared with those of non-irrigated grapevines during the three growing seasons. We postulated that waterlogging damage due to the increase in soil water content by frequent rainfall would be minimised by the selection of rootstock that confers tolerance to waterlogging stress for scion cultivars and/or viticultural practices to prevent decrease in soil temperature. Also, the introduction of Internet of Things technology for monitoring water status in vineyard soil is expected to contribute to improving practical approaches to vineyard soil water management.

Multiple drivers of seasonal and interannual variation in Pmax: Implications for leaf photosynthesis of Artemisia ordosica

2020 ◽  
Author(s):  
Yun Tian ◽  
Tianshan Zha ◽  
Xin Jia
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Growing Season ◽  
Dominant Factor ◽  
Equation Modeling ◽  
Leaf Nitrogen Content ◽  
Interannual Variations ◽  
Artemisia Ordosica ◽  
Seasonal And Interannual Variations

&lt;p&gt;Revealing the seasonal and interannual variations in leaf-level photosynthesis is a critical issue in understanding the ecological mechanisms underlying the dynamics of carbon dioxide exchange between the atmosphere and shrub ecosystem. &lt;em&gt;Artemisia ordosica&lt;/em&gt; is a dominant shrub species in semi-arid area of northwest China. Photosynthetic gas exchange, leaf nitrogen content(LN), specific leaf area (SLA) and some environmental factors were measured simultaneously on clear days (rotated every 10 days) of the growing season from 2011 to 2018, to quantify the temporal variations and environmental controls of photosynthetic parameters. Our results demonstrated that mean value of light-response curve parameters, the maximum photosynthetic capacity (P&lt;sub&gt;max&lt;/sub&gt;), appear quality efficiency (AQE), respiration in dark (R&lt;sub&gt;d&lt;/sub&gt;), light saturated point (LSP) and light compensated point (LCP) had a gradual decline with the growth (spring&gt; summer&gt;autumn). Structural equation modeling (SEM) was used to elucidate the direct and indirect effects of biophysical factors on P&lt;sub&gt;max&lt;/sub&gt;. The driven factors of P&lt;sub&gt;max&lt;/sub&gt; in growing season changed, but stomatal conductance (g&lt;sub&gt;s&lt;/sub&gt;) was the dominant factor in all stages. The g&lt;sub&gt;s&lt;/sub&gt; was influenced by SLA and LN&amp;#65292;and the soil water content at a depth of 10cm (SWC&lt;sub&gt;10&lt;/sub&gt;) affected the P&lt;sub&gt;max&lt;/sub&gt; in spring. In summer, P&lt;sub&gt;max &lt;/sub&gt;was significantly positively related with g&lt;sub&gt;s&lt;/sub&gt; and transpiration rate (T&lt;sub&gt;r&lt;/sub&gt;), and g&lt;sub&gt;s&lt;/sub&gt; was influenced by SLA, LN and soil water content at a depth of 30cm (SWC&lt;sub&gt;30&lt;/sub&gt;). In autumn, P&lt;sub&gt;max &lt;/sub&gt;was significantly positively correlated with g&lt;sub&gt;s&lt;/sub&gt;, while was significantly negatively correlated with air temperature (T&lt;sub&gt;a&lt;/sub&gt;). This simulation based on situ ecophysiological research suggest that P&lt;sub&gt;max&lt;/sub&gt; of &lt;em&gt;A. ordosica&lt;/em&gt; responded to the environment factors of seasonal and interannual variations, which is not the inherent genetic characteristics. Soil water content is the major environmental factor influencing P&lt;sub&gt;max&lt;/sub&gt; in spring and summer, while T&lt;sub&gt;a&lt;/sub&gt; is the major one in autumn. Knowledge of how environmental change will affect the photosynthesis of &lt;em&gt;A. ordosica&lt;/em&gt; in the future is essential for their protection, adaptation strategies and carbon fixation prediction in shrub ecosystems.&lt;/p&gt;

Photosynthesis and Stomatal-Conductance Responses of Johnsongrass (Sorghum halepense) to Water Stress

Weed Science ◽  
1985 ◽  
Vol 33 (5) ◽  
pp. 635-639 ◽  
Author(s):  
Bryan L. Stuart ◽  
Daniel R. Krieg ◽  
John R. Abernathy
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Osmotic Potential ◽  
Grain Filling ◽  
Leaf Temperature ◽  
Sorghum Halepense

The influence of water stress on johnsongrass [Sorghum halepense(L.) Pers. ♯ SORHA] physiology was evaluated in a semiarid environment. Stomatal conductance of johnsongrass responded to more negative leaf water potential and increasing leaf temperature. The sensitivity of the leaf temperature effect was dependent on the soil water content. At low soil water content, conductance was limited by low water potential, and increasing leaf temperature had little effect. Conductance of CO2was related to net photosynthesis in a curvilinear manner, with conductance levels greater than 0.3 mol·m-2· s-1being in excess of that necessary for maximum photosynthesis. At both high conductance levels and low levels associated with increased water stress, intercellular CO2concentration increased, indicating nonstomatal limitations to photosynthesis. Decreased osmotic potential provided the highest correlation with the linear decline of photosynthetic rate as stress intensified. The expression of osmotic adjustment in johnsongrass is reported during grain filling. Plants in the milkdough stage of grain filling had approximately 0.3 MPa lower osmotic potential at any relative water content than those at anthesis.

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