Application Research of Water-saving and Drought-resistant Landscape Plants:A Case Study of Inner Mongolia Drought-resistant Mongolian Grasses

Construction of "water-saving landscape architecture" is a crucial content of building "conservation-minded society'',an important approach of ensuring the sustainable development of landscaping industry.It targets at exploring a reasonable means of using the nature,so as to improve ecological conditions and environment,save resources and energies,and promote the harmonious coexistence of man and nature.Landscape plant is a significant component of landscape architecture,it is a key section to choose proper drought-resistant plant species for the landscape construction.

Application of Drought-resistant Varieties in Urban Green Spaces

As the connotations of urban green spaces and urban eco-green spaces have been more realized,drought-resistant green spaces have become a unique development trend,and drought-resistant flowers have been more applied in green spaces.This paper summarized characteristics of drought-resistant flowers,foreign and domestic researches in this field,advantages and disadvantages of their application in urban green spaces,and proposed key directions of the future researches.

Changes in DNA Methylation Pattern at Two Seedling Stages in Water Saving and Drought-Resistant Rice Variety after Drought Stress Domestication

Recent studies revealed that DNA methylation plays an important role in plant growth and development. In this study, a water-saving and drought-resistant rice variety Huhan 3 was subjected to drought stress from tillering to grain-filling stages in six successive growth cycles. The variations in DNA methylation pattern between the original generation （Go） and the sixth generation （G6） were analyzed by using methylation sensitive amplification polymorphism method. The results revealed that the methylated loci accounted for 34.3% to 34.8% of the total loci. Among these methylated loci, 83.1% to 84.8% were full- and hyper-methylated and 15.2% to 16.9% were hemi-methylated. The DNA methylation level decreased from the three-leaf to four-leaf stages in Huhan 3. Differentially methylated loci （DML） between generations or/and between different developmental stages accounted for 4.0% of the total loci, most of which were only related to plant development （57.9%）. Compared to Go, the DNA methylation pattern of G8 changed after drought domestication, at the three-leaf stage, de-methylation accounting for 59.1%, while at the four-leaf stage, re-methylation for 47.9%. Genome-wide alternations of DNA methylation were observed between the two seedling stages, and DML mainly occurred on the gene＇s promoter and exon region. The genes related to DML involved in a wide range of functional biology and participated in many important biological processes.

Responses of Drought-Resistant Mutant vem1 to Stress and Cloning of VEM1 Gene in Arabidopsis

[ Objective] This study aimed to investigate the responses of drought-resistant mutant veml to stress and clone VEM1 gene in Arabidopsis. [ Method] A drought-resistant mutant veml was isolated from the Arabidops/s mutant pool. The germination rates of wild-type （WT） and mutant veml were detected to investigate the responses of mutant veml to mannitol, NaCl and ABA stress. [ Result] The mutant veml was resistant to mannitol and NaC1 stress but sensitive to ABA stress. VEM1 gene was cloned by Tail-PCR technology and sequenced. The sequencing result was submitted to NCBI for sequence alignment and gene mapping using BLAST. Database analysis suggested that VEM1 gene was a transposable clement gene. [ Conclusion] This study laid the foundation for functional analysis of drought-resistant gene VEM1.

Effects of Water-Collecting and -Retaining Techniques on Photosynthetic Rates, Yield, and Water Use Efficiency of Millet Grown in a Semiarid Region

Field experiments were conducted in 2003 and 2004 to study the effects of plastic ridges and furrow film mulching （plastic film on sowing, as well as plastic film on flat soil and hole sowing） and chemicals （a drought resistant agent and a water- retaining agent） on growth, photosynthetic rate, yield, and water use efficiency （WUE） of spring millet （Setaria italica L.）. The experimental results showed that water-collecting and -retaining techniques can effectively increase soil moisture content, the leaf photosynthetic rate and crop growth. Due to increased soil moisture under the plastic-covered ridge and furrow water-collecting in July and August, dry matter and plant height had a increase at the booting stage （late growth advantage）. However, the plastic-covered flat soil and hole sowing reduced soil evaporation during early growth, the increase of dry matter and plant height appeared at the seedling stage （early growth advantage）. Plastic-covered ridge and furrow sowing supplemented with chemical reagents had significant positive effects on water collection and soil moisture retention. Improvement of soil moisture resulted into the increase of the photosynthetic rate, dry matter accumulation yield and WUE. The water-collecting and -retaining techniques can improve WUE and enhance crop yield. Correlation analysis demonstrated that the photosynthetic rate under the water-collecting and -retaining techniques was significantly associated with the soil moisture, but had no significant relationship with leaf chlorophyll content. Plastic- covered ridge and furrow sowing supplemented with chemical reagents increased the yield and WUE by 114% and 8.16 kg ha-1 mm-1, respectively, compared with the control; while without the chemical reagents the yield and WUE were 95% and 7.42 kg ha-1 mm-1 higher, respectively, than those of the control.

Cloning of the Soybean sHSP26 Gene and Analysis of Its Drought Resistance

Exploring the molecular mechanism of soybean response to drought stress,providing a basis for genetic improvement and breeding of heat-resistant varieties,relying on the transcriptome sequencing data of unpollinated ovary at the seven-leaf stage of soybean Jinong 18(JN18)and Jinong 18 mutant(JB18)soybeans,using reverse transcription,one gene in the sHSP family was cloned using PCR(RT-PCR)and it was named sHSP26.In this experiment,the soybean sHSP26 gene was successfully cloned by RT-PCR,the protein encoded by the sHSP26 gene was analyzed by bioinformatics,and the sHSP26 gene overexpression vector and CRISPR/Cas9 gene-editing vector were constructed.The positive plants were derived from Agrobacterium-mediated transformation of soybean cotyledon nodes,and T2 plants were identified through conventional PCR,QT-PCR,and Southern blot hybridization.Finally,through the determination of drought-related physiological and biochemical indicators and the analysis of agronomic traits,further research on gene function was conducted.The results indicated that the overexpression vector plant GmsHSP26 gene expression increased.After stress,the SOD and POD activities,and the PRO content of the transgenic overexpression plants increased,while the MDA content decreased.The reverse was true for soybean plants with genetically modified editing vectors.A survey of agronomic traits indicated that the fourpod ratio and yield per plant of the transgenic overexpression plants were higher than those of the control and transgenic editing vector soybean plants.It indicates that the expression of the sHSP26 gene can enhance drought resistance and soybean yield.The soybean sHSP26 gene cloning and its functional verification have not yet been reported.This is the first report where PCR amplification of soybean sHSP26 genes and gene expression vector were applied.It lays the foundation for creating new drought-resistant transgenic soybean lines through genetic engineering technology and is essential for improving soybean yield and quality.

Creation of an Agricultural Security System: An Effective Model of Sustainable Land Use

The article discusses the effective use of degraded foothill lands of the Kamashy district of the Kashkadarya region of Uzbekistan. Sustainable land use in the arid lands of the foothill zone, due to water conservation, growing seedlings of nut and fruit trees, growing fodder crops in row spacing, allows local livestock breeders to create a rational model of agroforestry system of land use. The organization and development of agroforestry will ensure sustainable land use, create additional jobs, increase household incomes and improve the standard of living of the population.