scholarly journals Observed increasing water constraint on vegetation growth over the last three decades

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenzhe Jiao ◽  
Lixin Wang ◽  
William K. Smith ◽  
Qing Chang ◽  
Honglang Wang ◽  
...  
Keyword(s):  
Water Deficit ◽  
Comprehensive Evaluation ◽  
Vegetation Productivity ◽  
Vegetation Growth ◽  
Influence Of Water ◽  
Explicit Consideration ◽  
Vegetation Water ◽  
Water Limitations ◽  
Water Surplus ◽  
Water Constraint

AbstractDespite the growing interest in predicting global and regional trends in vegetation productivity in response to a changing climate, changes in water constraint on vegetation productivity (i.e., water limitations on vegetation growth) remain poorly understood. Here we conduct a comprehensive evaluation of changes in water constraint on vegetation growth in the extratropical Northern Hemisphere between 1982 and 2015. We document a significant increase in vegetation water constraint over this period. Remarkably divergent trends were found with vegetation water deficit areas significantly expanding, and water surplus areas significantly shrinking. The increase in water constraints associated with water deficit was also consistent with a decreasing response time to water scarcity, suggesting a stronger susceptibility of vegetation to drought. We also observed shortened water surplus period for water surplus areas, suggesting a shortened exposure to water surplus associated with humid conditions. These observed changes were found to be attributable to trends in temperature, solar radiation, precipitation, and atmospheric CO2. Our findings highlight the need for a more explicit consideration of the influence of water constraints on regional and global vegetation under a warming climate.

scholarly journals Water-Mediated Electronic Structure of Oligopeptides Probed by Their UV Circular Dichroism, Absorption Spectra, and Time-Dependent DFT Calculations

2020 ◽  
Author(s):  
Anshuman Kumar ◽  
Siobhan E. Toal ◽  
David DiGuiseppi ◽  
Reinhard Schweitzer-Stenner ◽  
Bryan Wong
Keyword(s):  
Circular Dichroism ◽  
Absorption Spectra ◽  
Density Functional ◽  
Time Dependent ◽  
Water Model ◽  
Cd Spectra ◽  
Influence Of Water ◽  
Explicit Consideration ◽  
A Charge ◽  
Circular Dichroïsm

<p>We investigate the UV absorption spectra of a series of cationic GxG (where x denotes a guest residue) peptides in aqueous solution and find that the spectra of a subset of peptides with x = A, L, I, K, N, and R (and, to a lesser extent, peptides with x = D and V) vary as a function of temperature. To explore whether or not this observation reflects conformational dependencies, we carry out time-dependent density functional calculations for the polyproline II (pPII) and β-strand conformations of a limited set of tripeptides (x = A, V, I, L, and R) in implicit and explicit water. We find that the calculated CD spectra for pPII can qualitatively account for the experimental spectra irrespective of the water model. The reproduction of the <i>β</i>-strand UV-CD spectra, however, requires the explicit consideration of water. Based on the calculated absorption spectra, we explain the observed temperature dependence of the experimental spectra as being caused by a reduced dispersion (larger spectral density) of the overlapping NV<sub>2</sub> band and the influence of water on electronic transitions in the β-strand conformation. Contrary to conventional wisdom, we find that both the NV<sub>1</sub> and NV<sub>2</sub> band are the envelopes of contributions from multiple transitions that involve more than just the HOMOs and LUMOs of the peptide groups. A natural transition orbital analysis reveals that some of the transitions with significant oscillator strength have a charge-transfer character. The overall manifold of transitions, in conjunction with their strengths and characters, depends on the peptide’s backbone conformation, peptide hydration, and also on the side chain of the guest residue. It is particularly noteworthy that molecular orbitals of water contribute significantly to transitions in <i>β</i>-strand conformations. Our results reveal that peptide groups, side chains, and hydration shells must be considered as an entity for a physically valid characterization of UV absorbance and circular dichroism. </p>

scholarly journals ASSESSMENT OF PHYSIOLOGICAL AND MORPHOLOGICAL TRAITS OF PLANTS OF THE GENUS Fragaria UNDER CONDITIONS OF WATER DEFICIT – A STUDY REVIEW

2020 ◽  
Vol 19 (1) ◽  
pp. 21-39
Author(s):  
Marta Rokosa ◽  
Małgorzata Mikiciuk
Keyword(s):  
Water Deficit ◽  
Plant Species ◽  
High Water ◽  
Temperate Climate ◽  
Future Research ◽  
High Water Content ◽  
Species Response ◽  
Influence Of Water ◽  
Specific Species ◽  
Response To Water

The genus Fragaria belongs to the Rosaceae family. The most popular representatives of this species are the strawberry (Fragaria × ananassa Duch.) and wild strawberry (Fragaria vesca L.), whose taste and health benefits are appreciated by a huge number of consumers. The cultivation of Fragaria plants is widespread around the world, with particular emphasis on the temperate climate zone. Increasingly occurring weather anomalies, including drought phenomena, cause immense losses in crop cultivation. The Fragaria plant species are very sensitive to drought, due to the shallow root system, large leaf area and the high water content of the fruit. There have been many studies on the influence of water deficit on the morphological, biochemical and physiological features of strawberries and wild strawberries. There is a lack of research summarizing the current state of knowledge regarding of specific species response to water stress. The aim of this study was to combine and compare data from many research carried out and indicate the direction of future research aimed at improving the resistance of Fragaria plants species to stress related to drought. These plants show patterns of response to stress caused by drought, such as: osmotic adjustment, reduction of transpiration and photosynthesis, and increased efficiency of water use. Drought also causes significant changes in the composition and palatability of the fruit of the Fragaria plant species.

scholarly journals Soil-Based Vegetation Productivity Model for Coryell County, Texas

2020 ◽  
Vol 12 (13) ◽  
pp. 5240
Author(s):  
Bin Wen ◽  
Jon Bryan Burley
Keyword(s):  
Hydraulic Conductivity ◽  
Bulk Density ◽  
Cynodon Dactylon ◽  
Triticum Aestivum L ◽  
Soil Reaction ◽  
P Value ◽  
Cotton Lint ◽  
Vegetation Productivity ◽  
Vegetation Growth ◽  
Interaction Terms

Managers, scientists, planners and designers of landscapes are interested in systematic investigations, to predict the reconstruction of disturbed soil resources for optimum vegetation productivity. In this study, a predictive equation for estimating neo-soil plant growth in Coryell County, Texas was developed. The equation predicts the vegetation growth for wheat (Triticum aestivum L.), oats [Avena sativa L. (1753)], sorghum [Sorghum bicolor (L.) Moench], cotton lint (Gossypium hirsutum L.), Bermuda grass [Cynodon dactylon (L.) Pers.], and rangeland production in general. The results suggest that an all-vegetation predictive model was highly significant (p ≤ 0.0001), explaining over 80% of the variance. The equation employed hydraulic conductivity as a main-effect variable; bulk density and hydraulic conductivity as squared terms; and percent clay times bulk density, bulk density times soil reaction, hydraulic conductivity times available water holding capacity, and hydraulic conductivity times soil reactions as first order interaction terms, with each predicting variable containing a p-value equal to or less than 0.05. The results suggest that an annual crop equation and a plant-specific cotton lint equation also have merit.

scholarly journals Extreme Hydrologic Events in North Area of Buenos Aires Province (Argentina)

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Alberto Daniel Capriolo ◽  
Olga Eugenia Scarpati
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Water Deficit ◽  
Buenos Aires ◽  
Field Capacity ◽  
Soil Water Balance ◽  
Buenos Aires Province ◽  
Soil Water Deficit ◽  
Water Surplus ◽  
Wilting Point

This paper presents the soil water deficit and soil water surplus obtained from soil water balance in three drainage areas of Buenos Aires province for the period from 1971 to 2010. The soil water balance had been performed using the evapotranspiration formula of Penman-Monteith and considering the soil water constants: field capacity, soil water moisture, and soil wilting point for all the different types of soils of the region. The obtained soil water deficit and surplus are considered as triggers of extreme hydrologic events. Annual threshold values of 200 mm of soil water deficit and 300 mm of soil water surplus were considered for drought and flood, respectively. It was found that almost the 25% of the floods are severe and extreme while the 50% of droughts were of these intensities. Mann-Kendall statistical test was performed, and significance trends at level 0.1 were found for drought and for two periods, one of twenty years (1991–2010) and the other of ten years (2001–2010). As a sample of the temporal evolution of both events and their trends, the results of one locality (Junin) were deeply analyzed.

Study on The Extraction Method and Spatial-temporal Characteristics of Irrigated Land in Zhangjiakou City

2020 ◽  
Author(s):  
Zijuan Zhu ◽  
Lijun Zuo ◽  
Zengxiang Zhang ◽  
Xiaoli Zhao ◽  
Feifei Sun ◽  
...  
Keyword(s):  
Decision Tree ◽  
Extraction Method ◽  
Large Scale ◽  
Group Development ◽  
Development Trend ◽  
Mountainous Areas ◽  
Vegetation Growth ◽  
Vegetation Water Content ◽  
Decision Tree Classification ◽  
Vegetation Water

&lt;p&gt;In order to balance the economic and ecological interests, suitable farmland structures in different regions need be established which require understanding the current distribution pattern of irrigated and dry croplands, as well as the evolution rules and reasons of that. In this paper, irrigated croplands in 1985, 2000 and 2015 in Zhangjiakou city which is in the northwest from Beijing were extracted. The study area was divided into Bashang and Bxia aeras depending climate, terrain and agrotype. NDVIs and NDWIs from May to August reflecting vegetation growth and water indexes reflecting vegetation water content were adopted and decision tree classification method was employed. As a result, classification accuracies were high and meet the replying demand with 80.05% and 93.00% in Bashang and Baxia areas respectively. The classification results show that the area of irrigated lands was extended lightly, increasing about 12.73%, reached to 686127 km&lt;sup&gt;2&lt;/sup&gt;. Among them, there was 331438 km&lt;sup&gt;2&lt;/sup&gt; converted from dryland with the proportions as 54.45%. By contrast, about 272419 km&lt;sup&gt;2&lt;/sup&gt; irrigated croplands were transformed to drylands. But the plots areas of irrigated croplands were larger, showing a group development trend which is related to the large-scale development of the local vegetable industry in Bashang area. The total area of irrigated croplands was become bigger in intermontane plain around the rivers, while decreased in mountainous areas in Baxia area.&lt;/p&gt;

Influence of water deficit and rewatering on the components of the ascorbate–glutathione cycle in four interspecific Prunus hybrids

Plant Science ◽  
2005 ◽  
Vol 169 (2) ◽  
pp. 403-412 ◽  
Author(s):  
Adriano Sofo ◽  
Angelo Carmine Tuzio ◽  
Bartolomeo Dichio ◽  
Cristos Xiloyannis
Keyword(s):  
Water Deficit ◽  
Influence Of Water ◽  
Glutathione Cycle

scholarly journals Changes in carbohydrates accumulation in Viguiera discolor Baker in response to water deficit

Hoehnea ◽  
2019 ◽  
Vol 46 (4) ◽  
Author(s):  
Rodrigo Fazani Esteves Sanches ◽  
Ana Paula Oliveira da Silva ◽  
Vanessa Pires da Costa ◽  
Maria Ângela Machado de Carvalho ◽  
Emerson Alves da Silva
Keyword(s):  
Water Deficit ◽  
Osmotic Adjustment ◽  
Water Status ◽  
Soluble Sugars ◽  
Water Suppression ◽  
Adaptive Responses ◽  
Close Relationship ◽  
Relative Water ◽  
Influence Of Water ◽  
Response To Water

ABSTRACT Water stress is an environmental factor that can regulate growth, limit production and lead to physiological and biochemical changes. Plants present a series of adaptive responses to drought, such as osmotic adjustment, in which carbohydrates play an important role. To evaluate the influence of water deficit on carbohydrates accumulation in V. discolor, the plants were divided into two groups: daily watering and water suppression for 14 days being re-watering after this period. Leaves and roots were collected at 0, 3, 6, 9, 12, 15 and 18 days, for ecophysiological and biochemical analyzes. Variations in carbohydrate contents in V. discolor showed a close relationship with changes in the plant water status, with higher concentrations of soluble sugars, total fructans, oligosaccharides, reducing sugars coinciding with the lower values of soil moisture and leaf water potentials and relative water content. In the tuberous roots, there is an increase in carbohydrate concentrations after re-watering. The increase of these low molecular weight carbohydrates is involved in osmotic adjustment and therefore acts to protect against dehydration.

Sign in / Sign up

Export Citation Format

Share Document