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.

Agronomic performance of drought-resistance rice cultivars grown under alternate wetting and drying irrigation management in southeast China

Compared to drought-susceptible rice cultivars(DSRs),drought-resistance rice cultivars(DRRs)could drastically reduce the amount of irrigation water input and simultaneously result in higher grain yield under water-saving irrigation conditions.However,the mechanisms underlying these properties are unclear.We investigated how improved agronomic traits contribute to higher yield and higher water use efficiency(WUE)in DRRs than in DSRs under alternate wetting and drying(AWD).Two DRRs and two DSRs were field-grown in 2015 and 2016 using two different irrigation regimes:continuous flooding(CF)and AWD.Under CF,no statistical differences in grain yield and WUE were observed between DRRs and DSRs.Irrigation water under the AWD regime was 275–349 mm,an amount 49.8%–56.2% of that(552–620 mm)applied under the CF regime.Compared to CF,AWD significantly decreased grain yield in both DRRs and DSRs,with a more significant reduction in DSRs,and WUE was increased in DRRs,but not in DSRs,by 9.9%–23.0% under AWD.Under AWD,DRRs showed a 20.2%–26.2% increase in grain yield and an 18.6%–24.5% increase in WUE compared to DSRs.Compared to DSRs,DRRs showed less redundant vegetative growth,greater sink capacity,higher grain filling efficiency,larger root biomass,and deeper root distribution under AWD.We conclude that these improved agronomic traits exert positive influences on WUE in DRRs under AWD.

Development Prospect and Strategies of Water-saving and Drought-resistance Rice

Water-saving and drought-resistance upland rice has become a preferable choice for cotton farmlands ready for changing crops or paddy fields with water in short,because simplified and mechanical cultivation can be applied for the rice varieties of drought resistance and high yield.At present,it has been applied with an area of 400 000 hm2 in Hunan Province and the area continues growing.The research bred and introduced the relevant cultivation technology standard applicable to local water-saving and drought-resistance rice varieties in order to improve farmer＇s benefits.

Long-Term No-Tillage Direct Seeding Mode for Water-Saving and Drought-Resistance Rice Production in Rice-Rapeseed Rotation System

To study the effects of long-term no-tillage direct seeding mode on rice yield and the soil physiochemical property in a rice-rapeseed rotation system, a comparative experiment with a water-saving and drought-resistance rice （WDR） variety and a double low rapeseed variety as materials was conducted under no-tillage direct seeding （NTDS） mode and conventional tillage direct seeding （CTDS） mode for four years, using the CTDS mode as the control. Compared with the CTDS mode, the actual rice yield of WDR decreased by 8.10% at the first year, whereas the plant height, spikelet number per panicle, spikelet fertility, 1000-grain weight, grain yield, actual yield, and harvest index increased with no-tillage years, which led to the actual yield increase by 6.49% at the fourth year. Correlation analysis showed that the panicle length was significantly related to the actual yield of WDR. Compared with the CTDS mode in terms of the soil properties, the pH value of the NTDS mode decreased every year, whereas the contents of soil organic matter and total N of the NTDS mode increased. In the 0-5 cm layer of the NTDS mode, the soil bulk decreased, whereas the contents of soil organic matter, total N, and available N increased. In the 5-20 cm layer of the NTDS mode, the available N and K decreased, whereas the soil bulk, contents of soil organic matter, and total N increased. In summary, the NTDS mode increased the rice yield, and could improve the paddy soil fertility of the top layer.

Comparison of Drought-Resistance about Three Wild Rocky-Grasses

In this experiment, using the methods of drought-stress in the pot and PEG simulative drought-stress, three native rocky-slope grasses Pogonatherum panideum（Lam.） Hack, Erioophorum comosum nees and Cynodon dactylon cultivated in the pots were selected as materials to study their drought-resistance by analyzing the indexes such as the leaf area index, the drying roots accumulation, the holding water ability of leaf, the relative conductance of leaf, the soluble protein, chlorophyll. At the same time, by comparing with membership function value of each index, the order of each grass drought-resistance was decided. The results showed that the drought-resistance of Erioophorum comosum nees was stronger than Cynodon dactylon and drought-resistance of Cynodon dactylon was stronger than Pogonatherum panideum （Lam.） Hack. The purpose of the experimental results was to find theoretical foundations for selecting and cultivating native protecting-slope vegetations to adapt to rocky slopes.

玉米苗期抗旱性鉴定指标的研究

通过盆栽试验,以14个玉米杂交种(京科308、四单19、辽单565、吉单261、京科25、京单28、京科508、郑单958、京科516、DH3719、丹玉39、中丹808、农大108、京玉6为试验材料,研究了玉米苗期反复干旱对玉米株高、干物质积累、过氧化物酶活性、丙二醛含量、脯氨酸含量等的影响。分析表明,反复干旱胁迫下玉米各杂交种幼苗存活率与株高、干物质积累、POD含量呈正相关,与丙二醛含量、脯氨酸含量呈负相关,上述指标和幼苗反复干旱后存活率的相关性都达到显著水平。鉴定玉米苗期抗旱性以幼苗反复干旱后存活率为主,结合其他5项指标进行综合评价。

豌豆种质资源抗旱性鉴选与利用价值分析

为了鉴定筛选抗旱的豌豆种质资源及适宜在旱作雨养农业区生产中应用的优良品种(系),2008～2009年,在定西市旱农中心旱地试验地,采用田间自然鉴定方法,对来自全国主要豌豆产区七个省(市)的78份材料进行了抗旱性鉴定及筛选,以确定不同品种(系)在干旱条件下的抗旱性、综合农艺性状及产量表现。结果表明:17份材料属典型抗旱材料,6份为抗旱材料,10份为中等抗旱材料;在所有抗旱材料中,有8份材料各项筛选指标均较高,属抗旱性强、稳产性好的材料。

不同类型玉米杂交种的抗旱性和丰产性研究

利用半干旱区自然降水少的特点,采用田间直接鉴定法,在正常供水、干旱胁迫2种条件下,对不同类型玉米品种进行了抗旱性和丰产性研究,结果表明,在拔节前至大喇叭口期严重缺水124.4mm,干旱胁迫强度达0.20的情况下,密植型玉米品种总体上比稀植型品种表现出更好的抗旱性和丰产性。密植型品种抗旱指数平均达0.92,稀植型品种抗旱指数平均达0.74;正常供水条件下,密植型品种平均产量达11047kg/hm2,稀植型品种平均产量为9503kg/hm2。密植型品种抗旱和丰产的主要原因是在正常供水、干旱胁迫2种条件下,能形成较多的穗粒数。

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.

Advances in Research on the Approaches of Improving Water Utilization Efficiency in Rice

Water shortage is increasingly an important factor limiting the sustainable development of global economy, posing a hugethreat to social security and human existence. Water usage in agriculture accounts for about 70% of total water consumptionin the world, and rice cultivation is in turn the largest water user, which accounts for about 50% of total water usage inagriculture. Therefore, it is quite important to improve water utilization efficiency to reduce water consumption in rice.Water stress causes severe inhibition of plant growth and development as well as yield reduction, however the extent ofinhibition or reduction varies greatly with the growth stages, duration and severity of stress, and plant genotypes. In rice,drought resistance and water utilization efficiency might be improved by developing stress resistant cultivars and conductingproper agronomic practices. It is hence imperative to determine the suitable criteria in morphological and physiologicaltraits for drought resistance and water utilization efficiency in conventional breeding of rice. At present, leaf rolling, leafwater potential and carbon isotope discrimination are commonly used criteria for the evaluation and identification ofgermplasm with high drought resistance or water utilization efficiency. With rapid development of molecular biology,marker-assisted selection has been used in rice breeding against water stress. In this review, therefore, the agronomicaspect of water saving techniques such as selection of suitable rice cultivars, planting pattern, mulching, deficit irrigationand alternative drying and moist irrigation are discussed and effective approaches are also recommended.

Physiological Indices and Selection of Methods on Rapid Identification for Sweet Potato Drought Resistance

The relationships between the changes of relative water content （RWC）, malondialdehyde （MDA） contents, superoxide dismutase （SOD） activity and free proline contents in sweet potato leaves, and drought resistant ability under different concentration of polyethylene glycol （PEG） treatment applied at rhizosphere of sweet potato seedlings were studied. A highly positive correlation between RWC and drought resistance （r =0.783, P〈0.01）, a highly negative correlation between MDA contents and drought resistance （r = -0.848, P〈0.01）, a highly positive correlation between SOD activity and drought resistance （r = 0.777, P〈0.01） was observed. Free proline contents in leaves was not related obviously to the sweet potato drought resistance under 25% PEG treatment. The stronger the drought resistance of variety, the less decrease of RWC and increase of MDA contents, the more increase of SOD activity. By determining these physiological indices in sweet potato leaves under 25% PEG treatment, rapid identification of drought resistant ability of different varieties can be obtained in the lab.

Status and Perspectives of the Researches on Lawn

There is a rapid development of lawn industry, however, the researches on lawn culture, maintenance and its mechanisms lag behind. Studies of drought-resistance, fertilization, management and maintenance of lawn are discussed in this paper. Besides, problems with the research on lawn culture and its maintenance in China are also analyzed. For example, soil has been destroyed seriously by the production of wrapping sward, but the studies on turf medium are deficient. Besides, the maintenance and management of lawn have not a standard due to the shortage of studies on turf quality assessment; applications of high-technique to lawn sciences are inadequate too. The developing tendency of lawn research in China is suggested at the end of this paper to help for the further studies in this field.

Study on Diversity of Soybean Germplasm with Drought Resistance in Huang-Huai-Hai Region

Fifty soybean germplasms with drought resistance selected from Huang-Huai-Hai Region were studied under field drought condition. The results showed that there was a diversity of drought resistance at different growth stages. Some varieties had drought resistance in whole growing period, but some only at one stage or several stages. Some varieties had both drought resistance and higher yield characters, some with drought resistance but lower yield. It was also found in present study that some drought resistant germplasms

A new method to select the drought resistance azuki bean germplasm

120 azuki bean germplasms from different regions of China were selected for drought-resistance. Results showed that there is a significant positive correlation between drought-resistance and photooxidation-resistance. So, the detecting technique for photooxidation-resistance should be suggested as a reference method to select the drought-resistance germplasms in azuki bean.

Effect of Soil Drying Intensity During an Experimental Drying-Rewetting Event on Nutrient Transformation and Microbial Community Composition

Soil drying-rewetting(DRW) events affect nutrient transformation and microbial community composition; however, little is known about the influence of drying intensity during the DRW events. Therefore, we analyzed soil nutrient composition and microbial communities with exposure to various drying intensities during an experimental drying-rewetting event, using a silt loam from a grassland of northern China, where the semi-arid climate exposes soils to a wide range of moisture conditions, and grasslands account for over 40% of the nation's land area. We also conducted a sterilization experiment to examine the contribution of soil microbes to nutrient pulses. Soil drying-rewetting decreased carbon(C) mineralization by 9%–27%. Both monosaccharide and mineral nitrogen(N) contents increased with higher drying intensities(drying to ≤ 10% gravimetric water content), with the increases being 204% and 110% with the highest drying intensity(drying to 2% gravimetric water content), respectively, whereas labile phosphorus(P)only increased(by 105%) with the highest drying intensity. Moreover, levels of microbial biomass C and N and dissolved organic N decreased with increasing drying intensity and were correlated with increases in dissolved organic C and mineral N, respectively,whereas the increases in labile P were not consistent with reductions in microbial biomass P. The sterilization experiment results indicated that microbes were primarily responsible for the C and N pulses, whereas non-microbial factors were the main contributors to the labile P pulses. Phospholipid fatty acid analysis indicated that soil microbes were highly resistant to drying-rewetting events and that drought-resistant groups were probably responsible for nutrient transformation. Therefore, the present study demonstrated that moderate soil drying during drying-rewetting events could improve the mineralization of N, but not P, and that different mechanisms were responsible for the C, N, and P pulses observed during drying-rewetting events.