scholarly journals Photosynthetic response of mountain grassland species to drought stress is affected by UV-induced accumulation of epidermal flavonols

Beskydy ◽  
2016 ◽  
Vol 9 (1-2) ◽  
pp. 31-40 ◽  
Author(s):  
Barbora Rapantová ◽  
Karel Klem ◽  
Petr Holub ◽  
Kateřina Novotná ◽  
Otmar Urban
Keyword(s):  
Drought Stress ◽  
Uv Radiation ◽  
Protective Role ◽  
Interactive Effects ◽  
Summer Drought ◽  
Assimilation Rate ◽  
Grassland Species ◽  
Mountain Grassland ◽  
Negative Effect ◽  
Holcus Mollis

Interactive effects of drought and ultraviolet (UV) radiation on CO2 assimilation rate and accumulation of epidermal flavonols were studied in two herbs (Hypericum maculatum and Rumex obtusifolius) and two grasses (Agrostis capillaris and Holcus mollis) under field conditions of Beskydy Mts. The main objective of this study was to evaluate a protective role of epidermal flavonols against drought stress. Experimental shelters were used to manipulate amount of incident precipitation and UV radiation intensity for 12 weeks (May–July). The light-saturated CO2 assimilation rate (Amax) and the content of epidermal flavonols were regularly measured at intervals of 2–3 weeks during the entire period. Drought-induced reduction of Amax was enhanced by high UV intensity in R. obtusifolius, whereas in other species UV radiation reduced a negative effect of drought. Generally, drought increased flavonol content in leaves as compared to non-stressed plants. Similarly, high UV intensities increased the flavonol content in control plants, but not in drought-stressed ones. Regression analysis between the flavonol content and Amax revealed a positive correlation especially for A. capillaris and R. obtusifolius. In both species, a separation of these relationships was observed as the result of water availability. Thus lower Amax were observed at the same flavonol content in drought-stressed plants when compared to control, well-watered counterparts. We conclude that UV-induced accumulation of epidermal flavonols can alleviate negative impacts of summer drought on photosynthesis, particularly in species with slower ontogeny like H. maculatum and A. capillaris.

scholarly journals Evaluation of drought and UV radiation impacts on above-ground biomass of mountain grassland by spectral reflectance and thermal imaging techniques

Beskydy ◽  
2016 ◽  
Vol 9 (1-2) ◽  
pp. 21-30 ◽  
Author(s):  
Kateřina Novotná ◽  
Karel Klem ◽  
Petr Holub ◽  
Barbora Rapantová ◽  
Otmar Urban
Keyword(s):  
Drought Stress ◽  
Uv Radiation ◽  
Biomass Production ◽  
Thermal Imaging ◽  
Spectral Reflectance ◽  
Canopy Temperature ◽  
Stress Factors ◽  
Above Ground Biomass ◽  
Ground Biomass ◽  
Mountain Grassland

Drought represents one of the major factors limiting productivity of managed and natural ecosystems. Under natural field conditions drought is often associated with other stress factors such as high temperature and UV radiation, which may result in enhancement or vice versa alleviation of drought impact. Remote sensing methods have a large potential to evaluate impacts of drought on plant production at regional scale. The main objective of this study was to analyse the potential of ground-based measurement of spectral reflectance and thermal imaging for monitoring the impacts of drought and UV radiation on above-ground biomass production of mountain grassland ecosystem. Experimental rain-out shelters were used to manipulate incident precipitation and UV radiation for 7 weeks (May–July). A canopy spectral reflectance, thermal images, and total above-ground biomass were determined at the end of drought and UV treatment. Results show that drought led to a significant reduction of above-ground biomass, particularly under ambient UV radiation. In contrary, UV had only negligible effect on biomass production. Canopy temperature as well as selected spectral reflectance indices showed significant response to drought stress and also significant relationships to above-ground biomass. However, the relationship between canopy temperature and above-ground biomass is modified by UV radiation. Best prediction of changes in biomass caused by drought stress was provided by vegetation index NDVI.

A Physiological Approach to Study the Interaction of Cadmium and Zinc in Groundnut (Arachis hypogaea L.) Seedlings

2021 ◽  
Author(s):  
Debjani Dutta ◽  
Anjan Kumar Pal ◽  
Sunil Kumar Gunri
Keyword(s):  
Protein Content ◽  
Control Level ◽  
Protective Role ◽  
Interactive Effects ◽  
Sand Culture ◽  
Negative Effects ◽  
Zinc Supplement ◽  
Relative Water ◽  
Negative Effect ◽  
Varied Response

Background: Heavy metal toxicity affects plant growth and alters physiological processes. Soils in many areas are often contaminated by cadmium and zinc which show varied response on plants by their interactive effects. The experiment was done to study the effect of cadmium and zinc as sole presence and in combination in groundnut seedlings. Methods: The laboratory experiment was conducted on groundnut cultivar TG 51 in sand culture using modified Hoagland solution. After initial screening, three concentrations of cadmium (Cd 100, Cd 300 and Cd 500 µM) and two concentrations of zinc (Zn 50 and Zn 150 ìM) were selected for studying their effects individually and in combination on physiological and biochemical parameters. Result: The reduction in root length increased over control as the concentration of cadmium in the medium increased. Cadmium or zinc alone led to a decrease in chlorophyll a, b and relative water content of the leaf. Zinc supplement at 150 µM not only mitigated the negative effect of Cd 100 µM and 300 µM, but also increased the chlorophyll content above control level. Zinc supplement not only increased the protein content over the control but also mitigated to some extent the adverse effects of cadmium in protein content when applied in combination. Under both cadmium and zinc treatment, the inhibition of nitrate reductase (NR) activity over unstressed control was found. Different treatment combinations, however, reduced the negative effects of cadmium, although zinc could not completely override such damage, change the level of toxicity. Treatment with Cd 100 µM and 300 µM induced an increase in phenol content over the control, while higher concentration (500 µM) of the metal led to a decrease in this potent antioxidant compound. Presence of Zinc in the growing medium significantly enhanced the accumulation of phenolic compounds highlighting its protective role against oxidative damage.

Parenting Behaviors and Anxiety in Young Adults

2015 ◽  
Vol 36 (3) ◽  
pp. 170-176 ◽  
Author(s):  
Erin N. Stevens ◽  
Joseph R. Bardeen ◽  
Kyle W. Murdock
Keyword(s):  
Effortful Control ◽  
Parenting Behaviors ◽  
Protective Role ◽  
Anxiety Symptoms ◽  
Interactive Effects ◽  
Parental Overprotection ◽  
High Control ◽  
Development Of Anxiety ◽  
The Relationship

Parenting behaviors – specifically behaviors characterized by high control, intrusiveness, rejection, and overprotection – and effortful control have each been implicated in the development of anxiety pathology. However, little research has examined the protective role of effortful control in the relation between parenting and anxiety symptoms, specifically among adults. Thus, we sought to explore the unique and interactive effects of parenting and effortful control on anxiety among adults (N = 162). Results suggest that effortful control uniquely contributes to anxiety symptoms above and beyond that of any parenting behavior. Furthermore, effortful control acted as a moderator of the relationship between parental overprotection and anxiety, such that overprotection is associated with anxiety only in individuals with lower levels of effortful control. Implications for potential prevention and intervention efforts which specifically target effortful control are discussed. These findings underscore the importance of considering individual differences in self-regulatory abilities when examining associations between putative early-life risk factors, such as parenting, and anxiety symptoms.

Differences in the Way to Conceive Happiness Relate to Different Reactions to Negative Events

2018 ◽  
Vol 39 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Giulia Fuochi ◽  
Chiara A. Veneziani ◽  
Alberto Voci
Keyword(s):  
Positive Emotions ◽  
Satisfaction With Life ◽  
Well Being ◽  
Protective Role ◽  
Stressful Events ◽  
Interactive Effects ◽  
Negative Events ◽  
Orientations To Happiness ◽  
Specific Reactions ◽  
The Way

Abstract. This paper aimed to assess whether differences in the way to conceive happiness, measured by the Orientations to Happiness measure, were associated with specific reactions to negative events. We hypothesized that among orientations to pleasure (portraying hedonism), to meaning (representing a eudaimonic approach to life), and to engagement (derived from the experience of flow), orientation to meaning would have displayed a stronger protective role against recent negative and potentially stressful events. After providing a validation of the Italian version of the Orientations to Happiness measure (Study 1), we performed regression analyses of the three orientations on positive and negative emotions linked to a self-relevant negative event (Study 2), and moderation analyses assessing the interactive effects of orientations to happiness and stressful events on well-being indicators (Study 3). Our findings supported the hypotheses. In Study 2, meaning was associated with positive emotions characterized by a lower activation (contentment and interest) compared to the positive emotions associated with pleasure (amusement, eagerness, and happiness). In Study 3, only meaning buffered the effect of recent potentially stressful events on satisfaction with life and positive affect. Results suggest that orientation to meaning might help individuals to better react to negative events.

scholarly journals Soil Texture Alters the Impact of Salinity on Carbon Mineralization

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 128
Author(s):  
Ruihuan She ◽  
Yongxiang Yu ◽  
Chaorong Ge ◽  
Huaiying Yao
Keyword(s):  
Soil Texture ◽  
Clay Soil ◽  
Sandy Loam ◽  
Microbial Community Composition ◽  
Clay Content ◽  
Interactive Effects ◽  
Silty Clay ◽  
C Mineralization ◽  
Negative Effect ◽  
Silty Clay Soil

Soil salinization typically inhibits the ability of decomposer organisms to utilize soil organic matter, and an increase in soil clay content can mediate the negative effect of salinity on carbon (C) mineralization. However, the interactive effects of soil salt concentrations and properties on C mineralization remain uncertain. In this study, a laboratory experiment was performed to investigate the interactive effects of soil salt content (0.1%, 0.3%, 0.6% and 1.0%) and texture (sandy loam, sandy clay loam and silty clay soil with 6.0%, 23.9% and 40.6% clay content, respectively) on C mineralization and microbial community composition after cotton straw addition. With increasing soil salinity, carbon dioxide (CO2) emissions from the three soils decreased, but the effect of soil salinity on the decomposition of soil organic carbon varied with soil texture. Cumulative CO2 emissions in the coarse-textured (sandy loam and sandy clay loam) soils were more affected by salinity than those in the fine-textured (silty clay) soil. This difference was probably due to the differing responses of labile and resistant organic compounds to salinity across different soil texture. Increased salinity decreased the decomposition of the stable C pool in the coarse-textured soil, by reducing the proportion of fungi to bacteria, whereas it decreased the mineralization of the active C pool in the fine-textured soil through decreasing the Gram-positive bacterial population. Overall, our results suggest that soil texture controlled the negative effect of salinity on C mineralization through regulating the soil microbial community composition.

scholarly journals Decolorization of Methylene Blue by Ag/SrSnO3 Composites under Ultraviolet Radiation

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Patcharanan Junploy ◽  
Titipun Thongtem ◽  
Somchai Thongtem ◽  
Anukorn Phuruangrat
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Separation Process ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Negative Effect ◽  
Uv Visible

SrSn(OH)6 precursors synthesized by a cyclic microwave radiation (CMR) process were calcined at 900°C for 3 h to form rod-like SrSnO3. Further, the rod-like SrSnO3 and AgNO3 in ethylene glycol (EG) were ultrasonically vibrated to form rod-like Ag/SrSnO3 composites, characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron microscopy (EM), Fourier transform infrared (FTIR) spectroscopy, and UV-visible analysis. The photocatalyses of rod-like SrSnO3, 1 wt%, 5 wt%, and 10 wt% Ag/SrSnO3 composites were studied for degradation of methylene blue (MB, C16H18N3SCl) dye under ultraviolet (UV) radiation. In this research, the 5 wt% Ag/SrSnO3 composites showed the highest activity, enhanced by the electron-hole separation process. The photoactivity became lower by the excessive Ag nanoparticles due to the negative effect caused by reduction in the absorption of UV radiation.

Drought stress increases the expression of barley defence genes with negative consequences for infesting cereal aphids

2021 ◽  
Author(s):  
Daniel Leybourne ◽  
Tracy Valentine ◽  
Kirsty Binnie ◽  
Anna Taylor ◽  
Alison Jane Karley ◽  
...  
Keyword(s):  
Drought Stress ◽  
Aphid Species ◽  
Susceptible Variety ◽  
Aphid Resistance ◽  
Herbivorous Insects ◽  
Cereal Aphids ◽  
Negative Consequences ◽  
Resistant Plant ◽  
Negative Effect ◽  
The Impact

Crops are exposed to myriad abiotic and biotic stressors with negative consequences. Two stressors that are expected to increase under climate change are drought and infestation with herbivorous insects, including important aphid species. Expanding our understanding of the impact drought has on the plant-aphid relationship will become increasingly important under future climate scenarios. Here we use a previously characterised plant-aphid system comprising a susceptible variety of barley, a wild relative of barley with partial-aphid resistance, and the bird cherry-oat aphid to examine the drought-plant-aphid relationship. We show that drought has a negative effect on plant physiology and aphid fitness and provide evidence to suggest that plant resistance influences aphid responses to drought stress, with the expression of aphid detoxification genes increasing under drought when feeding on the susceptible plant but decreasing on the partially-resistant plant. Furthermore, we show that the expression of thionin genes, plant defensive compounds that contribute aphid resistance, increase ten-fold in susceptible plants exposed to drought stress but remain at constant levels in the partially-resistant plant, suggesting they play an important role in modulating aphid populations. This study highlights the role of plant defensive processes in mediating the interactions between the environment, plants, and herbivorous insects.

scholarly journals Effects of canopy-mediated abrasion and water flow on the early colonisation of turf-forming algae

2007 ◽  
Vol 58 (7) ◽  
pp. 657 ◽  
Author(s):  
Bayden D. Russell
Keyword(s):  
Water Flow ◽  
Interactive Effects ◽  
Light Penetration ◽  
Physical Processes ◽  
Percentage Cover ◽  
Negative Effect ◽  
Flow Through ◽  
Per Se ◽  
Reduced Light ◽  
Reduced Water

Algal canopies form predictable associations with the benthic understorey, and canopy-mediated processes may maintain these associations. Three canopy-mediated processes that are inherently linked are water flow through a canopy, abrasion of the substrate by the canopy, and light penetration. These processes were experimentally reduced to test the hypotheses that turf-forming algae would be: (1) positively affected by reduced abrasion by kelp canopies; (2) positively affected by reduced water flow; and (3) negatively affected by shading (reduced light). Biomass of turf-forming algae was greater when abrasion was reduced, but less when light was reduced. In contrast to predictions, reduced water flow had a negative effect on the percentage cover and biomass of turf-forming algae, rejecting the second hypothesis. It seems, however, that this negative effect was caused by an increase in shading associated with reduced canopy movement, not a reduction of water flow per se. None of the factors accounted for all of the change seen in understorey algae, indicating that it is important to study the interactive effects of physical processes.

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