[Research and Application Progress of Biochar in Amelioration of Saline-Alkali Soil].

Saline-alkali land， as one of the farmland problems that seriously threatens grain yield in the 21st century， is widely distributed and has great potential for development. Biochar is a relatively efficient novel soil amendment， which can play an important role in alleviating the soil acid-base barrier， soil pollution control， carbon sequestration， and fertilizer slow release and has a great prospect in promoting sustainable agricultural development. In recent years， the research and application of biochar to improve saline-alkali soil have attracted much attention. However， due to the complexity and heterogeneity of the structural components of biochar， the improvement effect of biochar on saline-alkali soil is highly uncertain， and there is also a lack of systematic summary and in-depth discussion of the key mechanisms， which limits the further popularization and application of biochar technology in the improvement of saline-alkali soil. This study comprehensively analyzed the effects of biochar on physicochemical properties， nutrient availability， and biological characteristics of saline-alkali soil； summarized the improvement effects of biochar and modified biochar on saline-alkali soil and their effects on quality and efficiency； and elucidated the possible mechanism of biochar in the improvement of saline-alkali soil. The future research prospect of biochar was discussed in order to provide reference for further research and development of green， efficient， and accurate improvement technology of biochar in saline-alkali soil and its popularization and application.

Application of a hospital-community-family trinity rehabilitation nursing model combined with motor imagery therapy in patients with cerebral infarction.

BACKGROUND: Rehabilitation nursing is considered an indispensable part of the cerebral infarction treatment system. The hospital-community-family trinity rehabilitation nursing model can provide continuous nursing services across hospitals, communities, and families for patients. AIM: To explore the application of a hospital-community-family rehabilitation nursing model combined with motor imagery therapy in patients with cerebral infarction. METHODS: From January 2021 to December 2021, 88 patients with cerebral infarction were divided into a study (n = 44) and a control (n = 44) group using a simple random number table. The control group received routine nursing and motor imagery therapy. The study group was given hospital-community-family trinity rehabilitation nursing based on the control group. Motor function (FMA), balance ability (BBS), activities of daily living (BI), quality of life (SS-QOL), activation status of the contralateral primary sensorimotor cortical area to the affected side, and nursing satisfaction were evaluated before and after intervention in both groups. RESULTS: Before intervention, FMA and BBS were similar (P > 0.05). After 6 months' intervention, FMA and BBS were significantly higher in the study than in the control group (both P < 0.05). Before intervention, BI and SS-QOL scores were not different between the study and control group (P > 0.05). However, after 6 months' intervention, BI and SS-QOL were higher in the study than in the control group (P < 0.05). Before intervention, activation frequency and volume were similar between the study and the control group (P > 0.05). After 6 months' intervention, the activation frequency and volume were higher in the study than in the control group (P < 0.05). The reliability, empathy, reactivity, assurance, and tangibles scores for quality of nursing service were higher in the study than in the control group (P < 0.05). CONCLUSION: Combining a hospital-community-family trinity rehabilitation nursing model and motor imagery therapy enhances the motor function and balance ability of patients with cerebral infarction, improving their quality of life.

[Identification of Bacterial Flora and Metabolic Function of Sediments in Different Channels of Duliujian River Basin, Tianjin].

Bacterial communities are highly sensitive to environmental changes, but their metabolic functions may be convergent under similar ecological conditions. In order to test this environmental attribute of the bacterial community and verify the feasibility in using the bacterial metabolic data to divide functional units at the river basin scale, the surface sediments in three continuous spatial units of the main stream (MS), left tributary (LT), and right tributary (RT) of the Duliujian River basin were selected as the research objects. Therefore, 16S rDNA high-throughput sequencing and the PICRUSt platform were used to analyze the bacterial diversity and metabolic function of sediments in different units. The results showed that there were no significant differences for the Shannon and Simpson indices between the different river channels (P>0.05); however, the bacterial diversity indices of Chao1, ACE, Observed_species, and PD_whole_tree of LT and RT were significantly higher than those of the MS (P<0.05). Moreover, the dominant bacterial phyla were not significantly different among the different river channels. In the present study, a total of 41 metabolic pathways were predicted based on the KEGG database, among which 34 metabolic pathways such as membrane transport, amino acid metabolism, and carbohydrate metabolism were significantly different. The functional metabolic abundance was higher in MS than that in RT and LT (P<0.05); however, there was no significant difference between those of RT and LT (P>0.05). Except for exchangeable phosphorus and nitrate nitrogen, there were no significant differences in other physicochemical properties among the different river channels (P>0.05). Furthermore, pH and iron/aluminum-phosphorus were found to significantly affect the bacterial structure, and SOM and TN were found to significantly affect the bacterial metabolic function. Overall, the sediments of MS and tributaries (LT and RT) of the river were clearly divided into level-1 and level-2 groups, indicating that the metabolic abundance of the bacterial community can be used as the key indicator in the division of functional units at the river basin scale. This study provided a theoretical basis and technical support for ecological functional division and management in coastal river basins.

[Characteristics and Factors of Soil Enzyme Activity for Different Plant Communities in Yellow River Delta].

Soil enzymes play key roles in the construction and succession of coastal wetland communities, while the driving mechanism of their activities under water and salt stress conditions is still unclear. The activities and distributions of sucrase, phosphatase, catalase, and urease in the rhizosphere and non-rhizosphere soils of Suaeda salsa, Phragmites australis, and Tamarix chinensis communities were studied in the Yellow River Delta. Moreover, the changes in soil enzyme activities and their influencing factors during the succession of halophytic plant communities were discussed in combination with changes in the physicochemical properties of soil. The results showed significantly higher soil enzyme activities and soil fertility parameters in the rhizosphere soils of S. salsa, P. australis, and T. chinensis communities than those in the non-rhizosphere soils (P<0.05). In the rhizosphere soils, the activities of phosphatase and catalase increased in the order of S. salsa < P. australis < T. chinensis, while they increased in the order of T. chinensis < S. salsa < P. australis for sucrase activity, and S. salsa < T. chinensis < P. australis for urease activity. Further, significant differences were found in the physicochemical properties of rhizosphere soils between different halophyte communities (P<0.05), which indicated that plant types and their rhizosphere effects could affect soil enzyme activities and fertility characteristics. Furthermore, a two-way analysis of variance showed that the rhizosphere effect was greater than that of vegetation type. The soil sucrase activity was significantly positively correlated with available potassium (AK), available phosphorus (AP), and ammonium nitrogen (NH4+-N) (P<0.05). Meanwhile, urease activity was significantly positively correlated with total nitrogen (TN), organic matter (SOM), AK, AP, NH4+-N, and nitrate nitrogen (NO3--N) (P<0.01). Both of the two enzymes were negatively correlated with soil electrical conductivity (EC) (P<0.01). The phosphatase and catalase activities were found to be significantly positively correlated with soil water content (MC), total carbon (TC), TN, total phosphorus (TP), SOM, AK, and NH4+-N (P<0.05). Additionally, parameters of pH, total potassium (TK), and NO3--N were also significantly associated with catalase activity. Finally, the redundancy analysis (RDA) revealed that main factors affecting the overall soil enzyme activity were TC (P<0.01), SOM (P<0.01), MC (P<0.01), TN (P<0.05), NH4+-N (P<0.05), and EC (P<0.05). The findings suggested that soil fertility, water, and salinity are the most influential factors of soil enzyme activity in different halophytic plant communities of the Yellow River Delta.

Nutrient enrichment alters impacts of Hydrocotyle vulgaris invasion on native plant communities.

Nutrients may affect the invasiveness of alien plants and the invasibility of native plant communities. We performed a greenhouse experiment to investigate the interactive effect of invasion by a clonal herb Hydrocotyle vulgaris and nutrient enrichment on biomass and evenness of native plant communities. We established three types of plant communities (H. vulgaris alone, native plant communities without or with H. vulgaris) under low and high levels of nutrients. Native communities consisted of eight native, terrestrial species of three functional groups, i.e. four grasses, two legumes, and two forbs. Invasion of H. vulgaris had no effect on biomass of the native community, the functional groups, or the individual species. High nutrients increased biomass of grasses, but reduced evenness of the community. High nutrients also decreased the competitive effect, and the relative dominance index of H. vulgaris. Therefore, high nutrients reduced the competitive ability of H. vulgaris and enhanced the resistance of the native community to invasion. The results provide a basis for management strategies to control the invasion and spread of H. vulgaris by manipulating resource availability to support native communities.

[Photosynthetic capacity and water use efficiency of tropical montane rainforest seedlings or saplings in Hainan Island].

By using a Li-6400 portable photosynthesis system, this paper measured the maximal photosynthetic capacity (P(max)) and water use efficiency (WUE) of the seedlings or saplings of 150 species of tropical montane rainforest in Hainan Island. The results showed that among the test 150 species, Quercus bambusifolia (Fagaceae) had the highest P(max) (13.27 micromol x m(-2) x s(-1)) and Macaranga denticulate (Euphorbiaceae) had the highest WUE (5.99 mmol x mol(-1)), while Decaspermum cambodianum (Myrtaceae) had the lowest P(max) (1.35 micromol x m(-2) x s(-1)) and Sapium discolor (Euphorbiaceae) had the lowest WUE (2.4 mmol x mol(-1)). The average P(max) was the highest in Moraceae but the lowest in Myrtaceae, and the average WUE was the highest in Symplocaceae but the lowest in Moraceae. However, there were no significant differences (P > 0.05) among the families. No significant differences (P > 0.05) in P(max) and WUE were also observed among arbors and shrubs. The P(max) value increased significantly (P < 0.05) with the widening of families' geographical distribution range, in the order of narrow distribution families < medium distribution families < wide distribution families, while no significant differences were existed among their WUE (P > 0.05). The P(max) value also increased with the widening of species' geographical distribution range, in the order of endemic species in Hainan Island < tropical species < tropical-subtropical species < tropical-subtropical-temperate species, but WUE was opposite to P(max), namely, in the order of endemic species in Hainan Island > tropical-subtropical species > tropical species > tropical-subtropical-temperate species.