Seedling desiccation tolerance of Leymus racemosus (Poaceae) (wild rye), a perennial sand-dune grass inhabiting the Junggar Basin of Xinjiang, China

2004 ◽  
Vol 14 (2) ◽  
pp. 233-239 ◽  
Author(s):  
Zhenying Huang ◽  
Yitzchak Gutterman
Keyword(s):  
Desiccation Tolerance ◽  
Sand Dune ◽  
Sand Dunes ◽  
Perennial Grass ◽  
Junggar Basin ◽  
Seedling Development ◽  
Ecological Implications ◽  
Leymus Racemosus ◽  
Seedling Desiccation Tolerance ◽  
Dune Grass

Leymus Racemosus, The Mammoth Wild Rye, Is A Rhizomatous Perennial Grass, Mainly Distributed In The Moving Or Semi-Stabilized Sand Dunes In Deserts Of The Junggar Basin In Xinjiang, China. The Revival Ability Of The Young Seedling After Periods Of Desiccation Can Be Influenced By Several Factors: (1) The Stage Of Seedling Development – The Later The Stage At Dehydration, The Longer The Root Length And The Lower Is The Percentage Of Seedlings That Survive; (2) The Length Of The Period Of Desiccation – The Longer The Period That The Seedlings Are Under Desiccation, The Lower Is The Percentage Of Seedlings That Survive; (3) Endosperm Size – The Smaller The Proportion Of Endosperm That Remains In The Caryopses, The Lower Is The Percentage Of Seedlings That Revive, Determined By (A) The Stage Of Seedling Development, And (B) The Proportion Of The Endosperm That Is Removed By Cutting; And (4) Caryopsis Size – The Larger The Polymorphic Caryopses, The Higher Is The Percentage Of Young Seedlings That Revive From Periods Of Desiccation. The Physiological And Ecological Implications Of L. Racemosus Seedling Desiccation Tolerance Are That Under Extreme Desert And Unpredictable Environmental Conditions, The Chances Of Seedling Establishment Are Increased.

Caryopsis dormancy, germination and seedling emergence in sand, of Leymus racemosus (Poaceae), a perennial sand-dune grass inhabiting the Junggar Basin of Xinjiang, China

2004 ◽  
Vol 52 (4) ◽  
pp. 519 ◽  
Author(s):  
Zhenying Huang ◽  
Ming Dong ◽  
Yitzchak Gutterman
Keyword(s):  
Seedling Emergence ◽  
Perennial Grass ◽  
Junggar Basin ◽  
Dry Weight ◽  
Germination Percentage ◽  
Burial Depth ◽  
Physiological Dormancy ◽  
Leymus Racemosus ◽  
Different Depths ◽  
Dune Grass

Leymus racemosus (Lam.) Tzvel. (Poaceae), wild rye, is an endangered, but economically important, perennial grass. It is mainly distributed in the moving or semistabilised sand in deserts of the Junggar Basin in Xinjiang, China. Freshly harvested caryopses are in non-deep physiological dormancy, causing slow and low germination. Six weeks of cold stratification at 5�C is required for the highest germination percentage to be reached at 25–30�C. Scarifying the fruit coat, or artificial removal of different proportions of the endosperm, also increases caryopsis germination. The greater the proportion of the endosperm that was removed, the higher the percentage of germination reached. However, the dry weight of the seedlings and the rate of root and shoot lengthening were significantly influenced by the proportion of the endosperm that remained on the caryopses.The influences of caryopsis size, or of the proportion of remaining endosperm, on germination and seedling emergence from different depths in sand were studied. The percentage of germination was negatively influenced by burial depth, but not by caryopsis size or the proportion of the endosperm that remained. Seedling emergence was negatively related to both burial depth and caryopsis or endosperm sizes. Seedlings from the smallest seeds or from caryopses with 75% endosperm removed did not emerge from 4 cm, and no seedlings from any of the treatments emerged from a depth of 8 cm.

Allelopathic potential of Artemisia campestris ssp. caudata on Lake Huron sand dunes

1997 ◽  
Vol 75 (11) ◽  
pp. 1903-1912 ◽  
Author(s):  
Kyeong W. Yun ◽  
M. A. Maun
Keyword(s):  
Seed Germination ◽  
Seedling Growth ◽  
Mycorrhizal Fungi ◽  
Sand Dune ◽  
Sand Dunes ◽  
Dry Weight ◽  
Fungal Colonization ◽  
Test Species ◽  
Allelopathic Potential ◽  
Artemisia Campestris

Greenhouse studies were conducted to test allelopathic effects of Artemisia campestris ssp. caudata on seed germination and seedling growth of several sand-dune species and colonization by mycorrhizal fungi. The aqueous extracts of A. campestris showed no inhibitory effect on seed germination, seedling elongation, or dry-weight growth of plants at lower concentrations (10 and 50%), but 100% concentration of the extracts caused varying degrees of inhibition depending on the test species. The mixing of dry leaves of seedlings of A. campestris to the sand showed severe inhibition of Elymus canadensis seedlings. The percent germination of test species in soil from the rhizosphere of A. campestris was significantly lower than that of the control. The leaf area and dry weight were also lower but the differences were not significant. The aqueous extract inhibited mycorrhizal fungal colonization in roots of three sand-dune grasses. Key words: allelopathy, Artemisia campestris ssp. caudata, seed germination, seedling growth, mycorrhizal fungi.

scholarly journals Modelling and  assessing driving factors of the spatial and temporal dynamics of the sand  dunes in the district of Errachidia, Morocco

2021 ◽  
Author(s):  
Tudal SINSIN ◽  
Fouad MOUNIR ◽  
Ahmed El ABOUDI
Keyword(s):  
Sand Dune ◽  
Temporal Dynamics ◽  
Moving Average ◽  
Sand Dunes ◽  
Ecological Factors ◽  
Temperature And Precipitation ◽  
Spatial And Temporal Dynamics ◽  
Combined Action ◽  
Landsat Satellite ◽  
Dune Dynamics

The desertification affects more than 250,000 ha in the district of Errachidia and results in the expansion of desert landscapes such as the Regs, Hamadas and the Dunes. The latter is a big concern in the district since it is the source of siltation, which threatens dwellings, cultivated lands and water bodies. It is of paramount importance to understand the causes and consequences of silting to develop strategies to combat it. Thus, first, we analysed the spatial and temporal dynamics of sand dunes until 2069 by applying the Seasonal Autoregressive Integrated Moving-Average (SARIMA) model on a time series of sand dune areas. These areas were calculated annually from 1987 to 2019 by computing the sand cover index (SCI) on Landsat satellite images. Furthermore, we evaluated the influence of different natural and human factors such as temperature, precipitation, wind, vegetation, and population growth, on sand dune dynamics using Spearman’s correlation test. The results indicated that the area of sand dunes will increase by 1.7% per year between 2019 and 2069 in the district of Errachidia. This increase would be mainly caused by the combined action of ecological factors, which vary from year to year. In general, temperature and precipitation act indirectly on wind and vegetation to influence the dynamics of sand dunes in hyper-arid areas where the soil is bare or poorly covered with vegetation, where precipitation is low and where temperature is high.

scholarly journals The Sources of Moisture in the Sand Dunes – The Example of the Western Sahara Dune Field

2014 ◽  
Vol 33 (3) ◽  
pp. 199-204 ◽  
Author(s):  
Elwira Żmudzka ◽  
Dariusz Woronko ◽  
Maciej Dłużewski
Keyword(s):  
Surface Layer ◽  
Moisture Content ◽  
Wind Velocity ◽  
Sand Dune ◽  
Sand Dunes ◽  
Shear Velocity ◽  
Meteorological Conditions ◽  
Aeolian Transport ◽  
Western Sahara ◽  
Dune Field

Abstract Climatic and meteorological conditions may limit the aeolian transport within barchans. An explanation of that issue was the main goal of the investigation held in Western Sahara dune fields located around Tarfaya and Laâyoune. Particular attention was paid to the factors causing the moisture content rising of the sand dune surface layer, which could influence the wind threshold shear velocity in the aeolian transport. The wetted surface layer of sand, when receiving moisture from precipitation or suspensions, reduces the aeolian transport, even in case of wind velocity above 4-5 m s-1. Fog and dew condensation does not affect the moisture of deeper sand layers, what occurs after rainfall.

Ecological aspects influencing the helminth community of the wood mouse Apodemus sylvaticus in Dunas de Mira, Portugal

2006 ◽  
Vol 51 (4) ◽  
Author(s):  
Catarina Eira ◽  
Jordi Torres ◽  
José Vingada ◽  
Jordi Miquel
Keyword(s):  
Species Richness ◽  
Sand Dune ◽  
Sand Dunes ◽  
Wood Mouse ◽  
Apodemus Sylvaticus ◽  
Habitat Characteristics ◽  
Helminth Community ◽  
Heligmosomoides Polygyrus ◽  
Ecological Aspects ◽  
Host Sex

AbstractThis paper presents the first extensive data on the helminth community of the wood mouse Apodemus sylvaticus in a coastal sand dune area in Portugal. The 557 hosts analysed in this study were trapped seasonally between autumn 2002 and summer 2005 across 6 habitat types. Twelve helminth species were detected among which, Taenia parva larvae, Angiostrongylus dujardini, Heligmosomoides polygyrus, Syphacia stroma and S. frederici constitute the component species, accounting for 98.7% of all worms. H. polygyrus was the most prevalent helminth parasite. Species richness varied according to habitat and season. The highest species richness was found in sand dunes during winter whereas the lowest was detected along lake margins also during the winter. Some differences in prevalence and mean intensity values were found in relation to year (T. parva larvae and H. polygyrus), habitat (A. dujardini), season (T. parva larvae, H. polygyrus, A. dujardini and S. stroma) and host sex (T. parva larvae and S. stroma). These differences are discussed both in view of the host’s biology and habitat characteristics.

Genetic basis of barley caryopsis dormancy and seedling desiccation tolerance at the germination stage

2004 ◽  
Vol 110 (3) ◽  
pp. 445-453 ◽  
Author(s):  
F. Zhang ◽  
G. Chen ◽  
Q. Huang ◽  
O. Orion ◽  
T. Krugman ◽  
...  
Keyword(s):  
Desiccation Tolerance ◽  
Genetic Basis ◽  
Seedling Desiccation Tolerance ◽  
Germination Stage

scholarly journals Integrated Geological, Hydrogeological, and Geophysical Investigations of a Barchan Sand Dune in the Eastern Region of Saudi Arabia

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 682
Author(s):  
Mohammed Benaafi ◽  
Sherif M. Hanafy ◽  
Abdullatif Al-Shuhail ◽  
Ammar El-Husseiny ◽  
Jack Dvorkin
Keyword(s):  
Grain Size ◽  
Saudi Arabia ◽  
Water Content ◽  
Sand Dune ◽  
Sand Dunes ◽  
Homogeneous Medium ◽  
Eastern Region ◽  
Large Area ◽  
Electrical Resistivity Survey ◽  
Dune Crest

In arid countries such as Saudi Arabia, aeolian sand often covers a large area of the country. Understanding the variations of sand properties in dunes, including grain size, sorting, mineral composition and water content, can be important for groundwater recharge, environmental, and construction applications. Earlier studies examined properties of sand dunes by collecting samples from the surface. This study aims to investigate variations of sand properties within a Barchan sand dune in the coastal area of Saudi Arabia, by collecting samples and measurements from two vertically drilled boreholes up to the ground water level; one drilled in the dune crest and another one in the limb. Representative samples were collected and analyzed for their texture parameters, water content, and mineralogy. Electrical resistivity survey data was also acquired to map water content variation in the dune limb, and for comparison with well bore data. The reported results show no vertical variations in grain size or sorting in the dune crest. In contrast, the upper 0.5 m of the dune limb shows a relatively poorer sorting than found in deeper parts of the dune. Laterally, no variations in minerology were observed between crest and limb sands while grain size tended to be slightly coarser in the dune limb compared to the crest. Regarding the water content, it was found to vary vertically, probably due to previous cycles of rainfall infiltration through the sand body. Such observed variation in water content is consistent with the measured resistivity profile which could clearly identify the water table and areas with higher water content. This study concludes that beyond the upper 0.5 m, the Barchan sand dune body can be treated as a homogeneous medium in terms of mineralogy and sorting while grain size increases slightly toward the limb side.

Adaptations of plants to burial in coastal sand dunes

1998 ◽  
Vol 76 (5) ◽  
pp. 713-738 ◽  
Author(s):  
M A Maun
Keyword(s):  
Sand Dune ◽  
Sand Dunes ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Threshold Level ◽  
Coastal Sand Dune ◽  
Bare Area ◽  
Plant Vigour ◽  
Storage Organs ◽  
Coastal Sand

One of the most obvious features on the foredunes and strands of coasts and lakes is recurrent burial in sand. Burial levels vary in different coastal sand dune systems and influence the physical and biotic microenvironment of the plant and soil. Foredune plants along coasts possess numerous adaptations to withstand burial. Studies show that below a certain threshold level of burial, the growth of all foredune plant species is stimulated probably because of multiple factors, namely improved soil resources, increase in soil volume, reactive plant growth, and enhanced mycorrhizal activity. However, as the level of burial increases, the positive response starts to decline until it becomes a negative value. For example, burial may reduce seed germination, seedling emergence, survival, and growth of seedlings and adult plants. At the community level, burial acts as a filter and selectively eliminates susceptible species, reduces the relative abundance of less tolerant species, and increases the abundance of tolerant and sand-dependent species. However, if sand deposition continues unabated, even the sand-dependent species are eliminated and a bare area is created. The emergence of a plant from a burial deposit primarily depends on the energy reserves in its storage organs and the speed, depth, and frequency of burial. Upon burial the plants shift resources from the belowground to the aboveground parts. Different plants show varied morphological responses to sand accretion. For example, the culms of grasses emerge by an increase in the number of nodes per culm and the elongation of internodes. Similarly, the emergent trunks and woody branches of tolerant trees and shrubs produce new buds and suckers at a higher level on the stem. In response to burial, the coastal sand dune species produce shootborne roots close to the new soil surface probably because of decreased oxygen levels.Key words: sand accretion, adaptations to burial, zonation of vegetation, burial of seeds, plant vigour, impact on communities, modes of emergence.

Macrofungi of sand dunes

1989 ◽  
Vol 96 ◽  
pp. 111-126 ◽  
Author(s):  
R. Watling ◽  
M. Rotheroe
Keyword(s):  
North America ◽  
Sand Dune ◽  
Sand Dunes ◽  
Dune Systems ◽  
Similarities And Differences

SynopsisOur knowledge of the macrofungi of British sand dune systems is outlined and similarities and differences are discussed, based both on intensive studies and scattered observations, particularly in Scotland and Wales. Comparisons are made with European sand dune communities, and much wider observations from as far afield as N.E. Australia and North America are presented. Several records new to Britain are documented.

Direct observation of fungal aggregates in sand dune soil

1978 ◽  
Vol 24 (3) ◽  
pp. 333-335 ◽  
Author(s):  
K. S. Clough ◽  
J. C. Sutton
Keyword(s):  
Sand Dune ◽  
Sand Dunes ◽  
Mycorrhizal Fungus ◽  
Lake Huron ◽  
Dominant Factor ◽  
Phaseolus Vulgaris L ◽  
External Mycelium ◽  
Grass Hosts ◽  
Dune Soil ◽  
Scanning Electron

The mycorrhizal fungus Glomus in association with bean hosts, Phaseolus vulgaris L., growing in pot cultures and grass hosts, Calamovilfa longiflora (Hook.) Scribn and Andropogon sp. growing on Lake Huron sand dunes produced extensive external mycelium. This mycelium was the dominant factor in the aggregation of soil particles. Light and scanning electron microscope studies indicated that the sand grains were attached to the hyphae. An amorphous deposit was often present at the interfaces of sand grains and hyphae. It appeared to act as an adhesive. Staining procedures indicated that this material contained polysaccharide. Other microorganisms were observed in association with the Glomus hyphae and the amorphous deposits.

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