scholarly journals Phenology and nurse plant of Sotoa confusa (Garay) Salazar (Orchidaceae) in the Southern Potosino Zacatecano Highlands

2019 ◽  
pp. 13-17
Author(s):  
Alejandro Muñoz-Urias ◽  
Claudia Aurora Uribe-Mú ◽  
Francisco Martín Huerta Martínez ◽  
Cecilia Neri-Luna
Keyword(s):  
Life History ◽  
Bare Soil ◽  
Negative Association ◽  
Arid Land ◽  
Survival Strategy ◽  
Arid Environments ◽  
Nurse Plant ◽  
Dodonaea Viscosa ◽  
Terrestrial Orchid ◽  
Semi Arid

Sotoa confusa is a little conspicuous terrestrial orchid that is distributed in arid and semi-arid land of Mexico and south of USA, its life history is poorly known, so phenology and interaction of this species with shrubs was studied; its bloom occurs in March and fructifies in April (the driest period of the year), latter, from July to September it develops leaves, which disappear in October, so this orchid remains eight months without leaves. By other hand, S. confusa does not grow in areas with bare soil, so it shows preference to grow under the canopy of plants such as Dodonaea viscosa, Opuntia imbricata, O. robusta, O. leucotricha and Pittocaulon praecox; however, it shows a negative association with Jatropha dioica. The survival strategy of this plant in arid environments is to grow under the canopy of other plants that provide a favorable microclimate and develop leaves only during rainy seasons.

scholarly journals Mosaic versus dual source approaches for modelling the surface energy balance of a semi-arid land

1999 ◽  
Vol 3 (2) ◽  
pp. 247-258 ◽  
Author(s):  
G. Boulet ◽  
A. Chehbouni ◽  
I. Braud ◽  
M. Vauclin
Keyword(s):  
Surface Energy ◽  
Bare Soil ◽  
Surface Fluxes ◽  
Surface Energy Budget ◽  
Arid Land ◽  
Data Sets ◽  
Sparse Vegetation ◽  
Land Surfaces ◽  
Using Data ◽  
Semi Arid

Abstract. Two-layer parameterisation of the surface energy budget proves to be realistic for sparse but homogeneously distributed vegetation. For semi-arid land surfaces however, sparse vegetation is usually interspersed by large patches of unshaded bare soil which may interact directly with the atmosphere with little interference with the vegetation. Therefore such surfaces might not be realistically represented by a two-layer parameterisation. The objective of this study is to investigate the issue of representing water and energy transfer processes in arid and semi-arid regions. Two different surface schemes, namely the classic two layer (one-compartment) approach and a two adjacent compartment ("mosaic") approach are used. The performance of both schemes is documented using data sets collected over two sparsely vegetated surfaces in the San Pedro river basin: homogeneously distributed grassland and heterogeneously distributed shrubs. In the latter case the mosaic scheme seems to be more realistic given the quality of the temperature estimates. But no clear statement can be made on the efficiency of both schemes for the total fluxes. Over each site, we investigate the possibility of artificially modifying some of the surface parameters in order to get the surface fluxes simulated by the one-compartment scheme to reproduce the two-compartment ones. The "cost" associated with this process in terms of surface temperature estimates is eventually discussed.

Small-scale patterns of abundance of mosses and lichens forming biological soil crusts in two semi-arid gypsum environments

2006 ◽  
Vol 54 (4) ◽  
pp. 339 ◽  
Author(s):  
I. Martínez ◽  
A. Escudero ◽  
F. T. Maestre ◽  
A. de la Cruz ◽  
C. Guerrero ◽  
...  
Keyword(s):  
Biological Soil Crust ◽  
Aggregate Stability ◽  
Bare Soil ◽  
Biological Soil Crusts ◽  
Small Scale ◽  
Arid Environments ◽  
Soil Variables ◽  
Constrained Ordination ◽  
Soil Crusts ◽  
Semi Arid

Despite important advances in the understanding of biological soil crusts and their key role in ecosystem processes in arid and semi-arid environments, little is known about those factors driving the small-scale patterns of abundance and distribution of crust-forming lichens and mosses. We used constrained ordination techniques (RDAs) to test the hypothesis that the spatial patterning of lichens and mosses is related to surface and subsurface soil variables in two semi-arid gypsum environments of Spain. Our results show that the abundance of mosses and lichens forming biological soil crusts was related to a limited set of variables (cover of bare soil and litter, soil respiration, potassium content and aggregate stability). Moreover, they provide some insights into the importance of these variables as drivers of biological soil-crust composition and abundance in semi-arid gypsum environments.

scholarly journals Exogenously Used 24-Epibrassinolide Promotes Drought Tolerance in Maize Hybrids by Improving Plant and Water Productivity in an Arid Environment

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 354
Author(s):  
El-Sayed M. Desoky ◽  
Elsayed Mansour ◽  
Mohamed M. A. Ali ◽  
Mohamed A. T. Yasin ◽  
Mohamed I. E. Abdul-Hamid ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Agronomic Traits ◽  
Water Productivity ◽  
Positive Association ◽  
Net Photosynthesis ◽  
Antioxidant Enzyme Activities ◽  
Severe Drought ◽  
Arid Environments ◽  
Maize Hybrids ◽  
Semi Arid

The influence of 24-epibrassinolide (EBR24), applied to leaves at a concentration of 5 μM, on plant physio-biochemistry and its reflection on crop water productivity (CWP) and other agronomic traits of six maize hybrids was field-evaluated under semi-arid conditions. Two levels of irrigation water deficiency (IWD) (moderate and severe droughts; 6000 and 3000 m3 water ha−1, respectively) were applied versus a control (well-watering; 9000 m3 water ha−1). IWD reduced the relative water content, membrane stability index, photosynthetic efficiency, stomatal conductance, and rates of transpiration and net photosynthesis. Conversely, antioxidant enzyme activities and osmolyte contents were significantly increased as a result of the increased malondialdehyde content and electrolyte leakage compared to the control. These negative influences of IWD led to a reduction in CWP and grain yield-related traits. However, EBR24 detoxified the IWD stress effects and enhanced all the above-mentioned parameters. The evaluated hybrids varied in drought tolerance; Giza-168 was the best under moderate drought, while Fine-276 was the best under severe drought. Under IWD, certain physiological traits exhibited a highly positive association with yield and yield-contributing traits or CWP. Thus, exogenously using EBR24 for these hybrids could be an effective approach to improve plant and water productivity under reduced available water in semi-arid environments.

Changing perceptions of the effect of plant phenolics on nutrient supply in the ruminant

1996 ◽  
Vol 47 (6) ◽  
pp. 829 ◽  
Author(s):  
JB Lowry ◽  
CS McSweeney ◽  
B Palmer
Keyword(s):  
Phenolic Compounds ◽  
Acute Toxicity ◽  
Protein Interactions ◽  
Nutrient Supply ◽  
Arid Environments ◽  
Plant Phenolics ◽  
Ruminant Nutrition ◽  
Forage Plants ◽  
Hydrolysable Tannins ◽  
Semi Arid

Mammalian metabolism of plant phenolics, initially studied in monogastric animals, gave an emphasis to their toxic and antinutrient effects. Subsequent studies in tropical ruminants and wild herbivores have highlighted the high levels than can occur in some diets and the extensive microbial modification and degradation that can occur in the tract. This paper reviews aspects of plant phenolics as they relate to ruminant nutrition in tropical or semi-arid environments in which some forage plants contain high levels of phenolic compounds. Effects range from occasional acute toxicity of hydrolysable tannins, to acetate-releasing microbial degradations that apparently enable certain phenolics to act as nutrients. The most important and complex effects are those due to tannin-protein interactions. Although these can clearly reduce feed intake, nutrient digestibilities, and protein availability, many of the interactions are still not understood. The diverse effects of plant phenolics on nutrient flow probably result from the balance between adverse effects on some organisms and the rate at which they are degraded or inactivated by other organisms, and improved animal performance can likely be obtained by manipulation of rumen microbial metabolism.

scholarly journals Modelling water utilization patterns in apple orchards with varying canopy sizes and different growth stages in semi-arid environments

2021 ◽  
Vol 283 ◽  
pp. 110051
Author(s):  
Nompumelelo Thelma Mobe ◽  
Sebinasi Dzikiti ◽  
Timothy Dube ◽  
Dominic Mazvimavi ◽  
Zanele Ntshidi
Keyword(s):  
Growth Stages ◽  
Arid Environments ◽  
Apple Orchards ◽  
Water Utilization ◽  
Utilization Patterns ◽  
Different Growth Stages ◽  
Semi Arid

scholarly journals Trade-off between reservoir yield and evaporation losses as a function of lake morphology in semi-arid Brazil

2016 ◽  
Vol 88 (2) ◽  
pp. 1113-1125 ◽  
Author(s):  
José N.B. Campos ◽  
Iran E. Lima Neto ◽  
Ticiana M.C. Studart ◽  
Luiz S.V. Nascimento
Keyword(s):  
Water Yield ◽  
Prediction Errors ◽  
Arid Environments ◽  
Triangle Diagram ◽  
Trade Off ◽  
The Real ◽  
Lake Morphology ◽  
Evaporation Losses ◽  
Semi Arid ◽  
Reservoir Yield

This study investigates the relationships between yield and evaporation as a function of lake morphology in semi-arid Brazil. First, a new methodology was proposed to classify the morphology of 40 reservoirs in the Ceará State, with storage capacities ranging from approximately 5 to 4500 hm3. Then, Monte Carlo simulations were conducted to study the effect of reservoir morphology (including real and simplified conical forms) on the water storage process at different reliability levels. The reservoirs were categorized as convex (60.0%), slightly convex (27.5%) or linear (12.5%). When the conical approximation was used instead of the real lake form, a trade-off occurred between reservoir yield and evaporation losses, with different trends for the convex, slightly convex and linear reservoirs. Using the conical approximation, the water yield prediction errors reached approximately 5% of the mean annual inflow, which is negligible for large reservoirs. However, for smaller reservoirs, this error became important. Therefore, this paper presents a new procedure for correcting the yield-evaporation relationships that were obtained by assuming a conical approximation rather than the real reservoir morphology. The combination of this correction with the Regulation Triangle Diagram is useful for rapidly and objectively predicting reservoir yield and evaporation losses in semi-arid environments.

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