Desertification and Its Control along the Qinghai-Tibet Railway

The Qinghai-Tibet Railway is a magnificent project in the twenty first century. However, the problem of land desertification has arisen during the operation of the railway. Many sections of the railway roadbed are buried by sand. The ecological safety along the railway and the safe operation of the railway have attracted worldwide attention. This chapter will focus on the current situation of desertification along the Qinghai-Tibet Railway, such as key desertification sections and the temporal and spatial characteristics of the occurrence of desertification. At the same time, it introduces the characteristics of the dynamic conditions of railway desertification and the source of sand material. It is divided into two parts: biological measures and engineering measures to introduce desertification control along the railway. The biological measures focus on the selection of Lolium perenne, Festuca sinensi, Elymus breviaristatus, Elymus nutans and Poa crymophila, and other alpine native sand-fixing plant materials. The engineering measures will introduce the railway desertification comprehensive prevention and control technology system that combines solidification, resistance, and transportation.

Soil Microbial Differences under Unpalatable Stellera Chamaejasme and Neighboring Palatable Elymus Nutans in Alpine Meadows

Stellera chamaejasme L. is a fast-spreading unpalatable poisonous plant that grows in the alpine grasslands of the Qinghai-Tibetan Plateau (QTP). The impacts of unpalatable plant species spread on animal health and plant community have been well studied, but studies into their effects on belowground organisms and processes are rare. We carried out a soil metabarcoding study using Illumina MiSeq sequencing to investigate whether the soil bacteria and fungi communities of Stellera are different to the soil microbiome of neighboring palatable grass Elymus nutans Griseb. Total carbon and nitrogen, the ratio of carbon to nitrogen, ammonium nitrogen, and microbial biomass carbon were all significantly greater in Stellera soil compared to Elymus soil, while no significant differences were observed for gravimetric soil moisture, pH or nitrate nitrogen. There were no significant differences in bacterial and fungal abundance between Stellera and Elymus soil. The bacterial species richness was significantly lower in Stellera soil but no significant difference was observed for fungal species richness. The beta diversity and community composition of bacteria and fungi were markedly different between soils. The presence of bacterial phyla Actinobacteria and Verrucomicrobia, and fungal phyla, Basidiomycota and Glomeromycota, were significantly greater under Stellera soil. This study demonstrated that the spread of undesirable unpalatable plants can potentially disrupt existing plant-soil-microbe associations with potential consequences for grassland soil biodiversity and ecosystem functioning.

Comprehensive evaluation of the allelopathic potential of Elymus nutans

Drooping wildryegrass (Elymus nutans) has been widely planted together with other perennial grasses for rebuilding degraded alpine meadow atop the Tibetan Plateau. However, the rebuilt sown pastures begin to decline a few years after establishing. One of the possible causes for degradation of sown grassland may come from allelopathy of planted grasses. The purpose of this study was to examine allelopathic potential of drooping wildryegrass. Three types aqueous extracts from drooping wildryegrass and its root zone soil were prepared and 5 highland crops and 5 perennial grasses were used as recipient plants. Drooping wildryegrass exhibited strong allelopathic potential on germination and seedling growth of 5 crops germination and growth, but different crops or perennial grasses respond to the extracts differently. The pieces extract has stronger inhibition than others. Hulless barley, oat and Chinese fescue were the most affected, while quinoa and Siberian wildryegrass were the least affected. Drooping wildryegrass presented less influence on Kentucky bluegrass and crymophylla bluegrass than on Chinese fescue. It is recommended that the species combination of mixture for restoration should consider allopathic effects of the co-seeding and decrease the seeding rate ratio of drooping wildryegrass. The annual dicot crop quinoa and rape seeds can be used as alternative subsequent crop for seed field of drooping wildryegrass monoculture.

The effect of Elymus nutans sowing density on soil reinforcement and slope stabilization properties of vegetation–concrete structures

Elymus nutans is an herbaceous plant that can be used to restore degraded alpine and subalpine ecosystems. Here, we evaluated how sowing density affects soil reinforcement and slope stabilization properties of vegetation–concrete structures. To investigate the optimal sowing density of E. nutans in vegetation–concrete applications for slope protection, six experimental treatments were established with different plant densities: control, I (1100 seeds/m2), II (2200 seeds/m2), III (3300 seeds/m2), IV (4400 seeds/m2), and V (5500 seeds/m2). Several parameters of plant growth in addition to soil reinforcement and slope stabilization properties were measured in each treatment, as well as the associations among parameters. As density increased, aboveground biomass continually increased, and plant heights, root surface areas, root lengths, and underground biomass all first increased and then decreased. In contrast, tiller numbers and the average root diameter gradually decreased with increasing density. Increased density also resulted in increased maximum water interception levels by aboveground stems and leaves. The maximum water interception by the aboveground stems and leaves was 41.75% greater in the highest density treatment (V) compared to the lowest density treatment (I). However, the enhancement of erosion resistance and soil shear strength first increased and then decreased as density increased, with maximal values observed in the medium-high density treatment (IV). Sowing density was highly correlated with aboveground biomass, plant heights, tiller numbers, and the maximum level of water interception by stems and leaves. Thus, sowing density directly influenced soil reinforcement and slope stabilization properties of aboveground plant components. However, density was not significantly correlated with belowground biomass, root lengths, root surface areas, the enhancement of erosion resistance, and soil shear strengths. Therefore, sowing density indirectly influenced soil reinforcement and slope stabilization of belowground plant components. Following from these results, we suggest that the optimal sowing density of E. nutans is approximately 4400 plants/m2 in their application within vegetation–concrete structures used for slope protection.

Effects of three-dimensional soil heterogeneity on seed germination in controlled experiments

Aims Seed germinations react to their local growing conditions, but the impacts of soil heterogeneity on seed germinations are not well known. Methods Effects of three-dimensional soil heterogeneity on seed germinations of grasses species were explored, where two levels of such soil heterogeneity were created via alternatively filling nutrient-poor and nutrient-rich substrate in pot in all directions. Patch sizes of the two heterogeneity levels are around 7.5 and 15 cm, respectively. Fifty seeds of each of the grasses species (Lolium perenne and Elymus nutans) were set either in these heterogeneous soils or in petri dishes with distilled water. Seed germinations of these species were daily recorded. Important Findings We found that pots with smaller patches had relatively lower germination rate, which is consistent with our expectation that shorter distance between nutrient-rich and nutrient-poor patches in pots with smaller patches allows plants to reduce their germination rates and delay their germination, in order to reduce the negative impacts of the strong variation of soil resources in these pots. Our results also revealed that pots with smaller patches yielded more heterogeneous seed germination, i.e. seed germinations highly diverged among these pots. These findings highlight that the realistic three-dimensional design can improve our understanding of seed germination as driven by soil spatial heterogeneity.

Recognizing Proteins with Binding Function in Elymus nutans Based on Machine Learning Methods

Background: We research the binding function proteins in Elymus nutans. Recognition for proteins is essential for study of biology. Machine learning methods have been widely used for the prediction of proteins. Methods: We used BLAST software for the function annotations of Elymus nutans. Besides, we used machine learning methods to recognize proteins which are not annotated by the software. In the process, we focused on identifying the proteins with binding functions. In our research, features are extracted by four algorithms, and then selected by mutual information estimator. Here three classifiers are constructed based on K-nearest neighbour algorithm and gradient boosting algorithm. Results and Conclusion: Experimental results show that there are 848 proteins with ATP binding function, 113 proteins with heme binding function, 315 proteins with zinc-ion binding function, 135 proteins with GTP binding function and 21 proteins with ADP binding function. Furthermore, we have successfully predicted the functions of 10 special protein sequences whose function annotations cannot be obtained by making sequence alignment with seven famous protein databases. Among them, seven sequences have ATP binding functions, one sequence has heme binding function, one sequence has zinc-ion binding function and the other one has GTP binding function.