Sand Fixing Research Articles

Isolation and Expression Analysis of Cu/Zn-Superoxide Dismutase Genes from ThreeCaraganaSpecies

Caragana is a native desert shrub with high forage values and stress tolerance, as well as sand fixing capabilities. Some Caragana species, including C. korshinskii, C. microphylla, and C. intermedia, are com monly used for vegetation restoration programs in the Loess Plateau region of northwestern China and are known to have ecological benefits and high commercial value. In this study, full length sequences of Cu/Zn SOD genes were isolated from three Caragana species using degenerate polymerase chain reaction (PCR) and rapid amplification of cDNA ends (RACE) techniques, and their expression under drought stress conditions were investigated. The cloned SOD cDNAs contained a predicted open reading frame (ORF) of 459 bp encoding a polypeptide of 152 amino acids with a theoretical molecular weight of 15.2 kD. Cu/Zn SOD cDNA of C. korshinskii and C. intermedia shared 100% sequence identity, implying a close relationship. A 24 bp specific sequence was found in the 3 UTR region of C. microphylla Cu/Zn SOD cDNA, and reverse tran scription RT PCR and genomic PCR confirmed the feasibility of the 24 bp sequence as a DNA marker for rapid variety identification of C. microphylla. RT PCR revealed that the expression of the Caragana Cu/Zn SOD genes was induced by PEG simulated drought stress and ABA. The three Caragana Cu/Zn SOD genes showed similar expression patterns, and no significant differences in transcriptional level were observed among the three genes. These results increase our understanding of the molecular mechanism of drought tol erance and can be used to improve vegetation restoration programs of Caragana plants.

The New Modes of Desert Governance

Desertification has caused great harms to the ecological environment and socio-economic. Through many years test in Xinjiang desert area, some useful modes of desert governance can be implemented: (1) making use of advanced water-saving irrigation technology; (2) combining reasonable cropping patterns with higher economic value plants like arbors, shrubs and medicinal herbs planted in the desert, which not only plays the roles of windbreak and sand fixing, but also can gain some economic, ecological and social benefits.

Effects of Artificial Sand Fixing on Community Characteristics of a Rare Desert Shrub

Eremosparton songoricum (Fabaceae) is a rare, native, clonal small shrub of the deserts of central Asia. Although human activities have greatly fragmented the distribution of E. songoricum, it occurs in areas where artificial sand fixing (AS) has been implemented. We sought to explore whether AS promotes survival and growth of E. songoricum. In the Gurbantunggut Desert of northwestern China in June 2010, we established 10 plots in an area where sand fixing occurred (5-10 years previously) and 11 plots on original sand substrate on which some plants had settled without fixing sand. Sand fixing changed soil properties and biological characteristics in sand-fixed plots. The soil surface where sand fixing occurred was covered by algal crusts and some lichen, but not bare sand (BS). Soil nutrients; water content of deep soil (30-150 cm); overall plant and herbaceous species richness, diversity, abundance, and cover; above- and belowground biomass; and cover, biomass, and height of E. songoricum in the sand-fixed plots were significantly greater than in plots of BS. However, distribution of E. songoricum individuals in the 2 types of plots did not differ. Our results indicate AS may enhance survival of E. songoricum and increase the overall diversity and stability of the desert plant community. We suggest AS as a way to protect this rare desert plant in situ.

Effects of Sand Burial Depth on Seedling Growth of <i>Caragana microphylla</i>

Caragana microphylla is a pioneer leguminous shrub species, and plays an important role in sand fixing and desertification control in the Horqin Sandy Land of Northern China. In this study, seedlings were buried by sand to depths of 0 (control), 1/3, 2/3, 1 and 4/3 of their mean height, and the effects of sand burial depth on seedling growth of Caragana microphylla were tested. Results show that with increasing burial depth, biomass allocation to leaves decrease, while stem biomass allocation increase, and both shoot and root growth of C. microphylla are stimulated and seedling biomass is the highest when burial depth is 2/3 of seedling height. Therefore, moderate burial could facilitate seedlings growth of C. microphylla

Study on Resistance of Wind/Sand Erosion Based on a Solidifying Composite Material of Hydrophilic Polyurethane

A novel solidifying composite material based on hydrophilic polyurethane (abbreviated as W-OH) is used as a sustainable sand-fixing material. The objective of this study was to investigate the actual function of desertification control using W-OH to fix sand from the Qinghai Lake basin. In the first experiment, the effects of sand fixing and resistance of wind/sand erosion were studied by wind tunnel testing. The wind/sand erosion modulus was measured and studied by setting the wind-sand flow velocity to 10m/s, 15m/s, 20m/s or 25m/s and the direction to 0°, 30° or 60°, respectively. A field demonstration was constructed in the Qinghai Lake basin to investigate the actual effects on sand fixation outdoors. The results of wind tunnel testing showed that W-OH can well fix the sand of the Qinghai Lake basin. The sand-fixing layer formed by a W-OH concentration of 3% remained intact under the action of a 25-m/s wind and sand flow. W-OH concentrations of 4% and 5% showed excellent resistance to wind/sand erosion. In the demonstration, the area without W-OH treatment had an amount of 15g/m2/h of windblown sand on average, and the area tacked with a W-OH concentration of 2% showed a reduced amount of windblown sand. However, the area was still seriously damaged by wind/sand erosion. The area treated with a W-OH concentration of 3% showed good resistance to wind/sand erosion without any damage during a 49-day test.

Controlling degradation and physical properties of chemical sand fixing agent‐poly(aspartic acid) by crosslinking density and composites

AbstractPoly(aspartic acid) (PASP) hydrogel crosslinked with 1,6‐ hexamethylene diamine was applied as sand fixing agent. The effect of crosslinking density of sand fixing agent on sand fixing property was studied. The relations between the degradation time and crosslinking density, sand fixing property, molecular weight, and mass loss were measured. It was found that the sand fixing property relied on the PASP crosslinking density and degradation time. The crust attained the maximal mechanical strength when the PASP crosslinking agent concentration was 0.0325 mol/L and the PASP hydrogel mass loss was 97.9% after 18 days. The composites added into PASP could increase mechanical property and prolong the degradation time when compared with the control. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Application and appreciation of chemical sand fixing agent-poly (aspartic acid) and its composites

The sand fixing agent-poly (aspartic acid) (PASP) and its composites were applied in the field by two forms (spraying around by PASP solution and PASP powder directly). It was found that the sand fixing effect in powder form was not as good as in solution form, but it was more practical in dry region. It needed 9, 6 and 7 days for PASP, xanthan gum-PASP (X2) and ethyl cellulose-PASP (E3) to attain the maximal mechanical strength after they were applied, respectively. The sand fixing effect decreased when the material was subjected to repeated hydration–dehydration cycles and the material had no negative influence on plant growth. The PASP and its composites had water-retaining ability and could reduce the water evaporation.

Present-day dune environment dynamics on the coast of the Świna Gate Sandbar (Polish West coast)

In present day Polish coastal dunes' development, heavy storms and human activity play a significant role. Natural or almost natural dune processes and accumulation of the coast is observed only in a few places, such as the Świna Gate Sandbar (also called barrier). As far as the spit number and morphology of the youngest ridges is concerned, they are different in the western, the middle and the eastern part. In the western part, ridges are smaller and closer to each other, thus depressions between them are narrower. Moreover, beach is widely covered by small hillocks. In the middle part, ridges are higher but narrower. Likewise, depressions between them are wider. The beach is wide and covered by large numbers of plants and dune hillocks. In the eastern part, dunes are also high but tend to be narrow, with steep seaside slope having the most frequent occurrence. Depressions and beach are narrow. The number of plants is not considerable compared with other parts. Since 1997 an increase of the new dune ridge on the still developing beach has been observed. Each year the beach is becoming wider and covered by larger number of plants. Plants lead to the development of new dunes and increase of the sandbar. The new foredune ridge consists of several hillocks joined into irregular ridge. This new first ridge is also shaped by storm waves but still becomes a real ridge. This development may be caused by continuous sand supply and by very strong north and west winds. A lot of different dune psammophyties on the beach are in favour of sand fixing on the increasing beach far from the first ridge. Only on part of spit with a tendency to erosion, accumulation of the dunes is not to be observed. Additionally, human activity stops aeolian accumulation and plant growth on the beach.

Osservazioni Anatomiche e FenologicheSu Diotis MaritimaDesf

Summary The Author studies the anatomy and phenology of Diotis maritima Desf. which grows along the sea shores of Messina (Sicily) as a sand fixing psammophyte.