Subjects: Biology >> Botany submitted time 2024-07-31 Cooperative journals: 《干旱区科学》
Abstract： Savanna, semi-deserts, and hot deserts characterize the Saharo-Arabian region, which includes Morocco, Mauretania, Algeria, Tunisia, Libya, Egypt, Palestine, Kuwait, Saudi Arabia, Qatar, Bahrain, the United Arab Emirates, Oman, Yemen, southern Jordan, Syria, Iraq, Iran, Afghanistan, Pakistan, and northern India. Its neighboring regions, the Sudano-Zambezian region belonging to the Paleotropical Kingdom and the Mediterranean and Irano-Turanian regions included in the Holarctic Kingdom, share a large portion of their flora with the Saharo-Arabian region. Despite the widespread acknowledgment of the region's global importance for plant diversity, an up to date list of the Saharo-Arabian endemics is still unavailable. The available data are frequently insufficient or out of date at both the whole global and the national scales. Therefore, the present study aims at screening and verifying the Saharo-Arabian endemic plants and determining the phytogeographical distribution of these taxa in the Egyptian flora. Hence, a preliminary list of 429 Saharo-Arabian endemic plants in Egypt was compiled from the available literature. Indeed, by excluding the species that were recorded in any countries or regions outside the Saharo-Arabian region based on different literature, database reviews, and websites, the present study has reduced this number to 126 taxa belonging to 87 genera and 37 families. Regarding the national geographic distribution, South Sinai is the richest region with 83 endemic species compared with other eight phytogeographic regions in Egypt, followed by the Isthmic Desert (the middle of Sinai Peninsula, 53 taxa). Sahara regional subzone (SS1) distributes all the 126 endemic species, Arabian regional subzone (SS2) owns 79 taxa, and Nubo-Sindian subzone (SS3) distributes only 14 endemics. Seven groups were recognized at the fourth level of classification as a result of the application of the two-way indicator species analysis (TWINSPAN) to the Saharo-Arabian endemic species in Egypt, i.e., I Asphodelus refractus group, II Agathophora alopecuroides var. papillosa group, III Anvillea garcinii group, IV Reseda muricata group, V Agathophora alopecuroides var. alopecuroides group, VI Scrophularia deserti group, and VII Astragalus schimperi group. It's crucial to clearly define the Saharo-Arabian endemics and illustrate an updated verified database of these taxa for a given territory for providing future management plans that support the conservation and sustainable use of these valuable species under current thought-provoking devastating impacts of rapid anthropogenic and climate change in this region.
Subjects: Biology >> Botany submitted time 2024-07-31 Cooperative journals: 《干旱区科学》
Abstract： The presence of invasive plant species poses a substantial ecological impact, thus comprehensive evaluation of their potential range and risk under the influence of climate change is necessary. This study uses maximum entropy (MaxEnt) modeling to forecast the likelihood of Leucaena leucocephala (Lam.) de Wit invasion in Saudi Arabia under present and future climate change scenarios. Utilizing the MaxEnt modeling, we integrated climatic and soil data to predict habitat suitability for the invasive species. We conducted a detailed analysis of the distribution patterns of the species, using climate variables and ecological factors. We focused on the important influence of temperature seasonality, temperature annual range, and precipitation seasonality. The distribution modeling used robust measures of area under the curve (AUC) and receiver-operator characteristic (ROC) curves, to map the invasion extent, which has a high level of accuracy in identifying appropriate habitats. The complex interaction that influenced the invasion of L. leucocephala was highlighted by the environmental parameters using Jackknife test. Presently, the actual geographic area where L. leucocephala was found in Saudi Arabia was considerably smaller than the theoretical maximum range, suggesting that it had the capacity to expand further. The MaxEnt model exhibited excellent prediction accuracy and produced reliable results based on the data from the ROC curve. Precipitation and temperature were the primary factors influencing the potential distribution of L. leucocephala. Currently, an estimated area of 216,342 km2 in Saudi Arabia was at a high probability of invasion by L. leucocephala. We investigated the potential for increased invasion hazards in the future due to climate change scenarios (Shared Socioeconomic Pathways (SSPs) 245 and 585). The analysis of key climatic variables, including temperature seasonality and annual range, along with soil properties such as clay composition and nitrogen content, unveiled their substantial influence on the distribution dynamic of L. leucocephala. Our findings indicated a significant expansion of high risk zones. High-risk zones for L. leucocephala invasion in the current climate conditions had notable expansions projected under future climate scenarios, particularly evident in southern Makkah, Al Bahah, Madina, and Asir areas. The results, backed by thorough spatial studies, emphasize the need to reduce the possible ecological impacts of climate change on the spread of L. leucocephala. Moreover, the study provides valuable strategic insights for the management of invasion, highlighting the intricate relationship between climate change, habitat appropriateness, and the risks associated with invasive species. Proactive techniques are suggested to avoid and manage the spread of L. leucocephala, considering its high potential for future spread. This study enhances the overall comprehension of the dynamics of invasive species by combining modeling techniques with ecological knowledge. It also provides valuable information for decision-making to implement efficient conservation and management strategies in response to changing environmental conditions.
Subjects: Biology >> Botany submitted time 2024-07-31 Cooperative journals: 《干旱区科学》
Abstract： Rising atmospheric CO2 (carbon dioxide) concentrations and salinization are manifestations of climate change that affect plant growth and productivity. Species with an intermediate C3-C4 type of photosynthesis live in a wide range of precipitation, temperature, and soil quality, but are more often found in warm and dry habitats. One of the intermediate C3-C4 photosynthetic type is C2 photosynthesis with a carbon concentration mechanism (CCM) that reassimilates CO2 released via photorespiration. However, the ecological significance under which C2 photosynthesis has advantages over C3 and C4 plants remains largely unexplored. Salt tolerance and functioning of CCM were studied in plants from two populations (P1 and P2) of Sedobassia sedoides (Pall.) Freitag & G. Kadereit Asch. species with C2 photosynthesis exposed to 4 d and 10 d salinity (200 mM NaCl) at ambient (785.7 mg/m3, aCO2) and elevated (1571.4 mg/m3, eCO2) CO2. On the fourth day of salinity, an increase in Na+ content, activity catalase, and superoxide dismutase was observed in both populations. P2 plants showed an increase in proline content and a decrease in photosynthetic enzyme content: rubisco, phosphoenolpyruvate carboxylase (PEPC), and glycine decarboxylase (GDC), which indicated a weakening of C2 and C4 characteristics under salinity. Treatment under 10 d salinity led to an increased Na+ content and activity of cyclic electron flow around photosystem I (PSI CEF), a decreased content of K+ and GDC in both populations. P1 plants showed greater salt tolerance, which was assessed by the degree of reduction in photosynthetic enzyme content, PSI CEF activity, and changes in relative growth rate (RGR). Differences between populations were evident under the combination of eCO2 and salinity. Under long-term salinity and eCO2, more salt-tolerant P1 plants had a higher dry biomass (DW), which was positively correlated with PSI CEF activity. In less salt-tolerant P2 plants, DW correlated with transpiration and dark respiration. Thus, S. sedoides showed a high degree of photosynthetic plasticity under the influence of salinity and eCO2 through strengthening (P1 plants) and weakening C4 characteristics (P2 plants).
Subjects: Biology >> Microbiology Subjects: Biology >> Botany submitted time 2024-07-10
Abstract： Plants evolved sophisticated genetic and metabolic mechanisms to shape their “core microbiome” under normal growth conditions. However, whether natural plant ecotypes re-shape a core “stress responsive microbiome” remains elusive. Considering that drought is the most serious abiotic stress worldwide, we conducted comparative microbiome analysis to study the potential conserved core root microbiome changes upon drought stress in natural Arabidopsis ecotypes. We screened the drought tolerance of 130 worldwide Arabidopsis ecotypes, and chose the extremely drought tolerant and sensitive ecotypes for comparative microbiome studies. We detected diverse differentially abundant ASVs , network driver taxa, as well as key functions pathways shared in diverse ecotypes upon drought stress, indicating the existence of some core drought-responsive microbiome changes. Our work unveiled the existence of a core drought-responsive microbiome and its critical role in enhancing plant fitness. This work also provided a research paradigm for guiding the discovery of stress-alleviating microbiomes in sustainable agriculture using natural ecotypes.
Peer Review Status:
Awaiting Review
Subjects: Biology >> Botany submitted time 2024-06-02 Cooperative journals: 《广西植物》
Abstract： To investigate the characteristics of the fungal community and potential key pathogens, ITS rDNA gene amplicon sequencing technology and FUNGuild analysis were used to study the fungal community composition, network characteristics and ecological function groups in rotting tubers of Dioscorea. sp. Additionally, potential pathogenic fungi were isolated and identified. The results were as follows: ( 1 ) In rotting tubers of Dioscorea sp., the dominant phylum was Ascomycota, and prevalent fungal genera included Penicillium, Colletotrichum, Fusarium, Talaromyces, Clonostachys, etc. The fungal molecular ecological network exhibited a clear modular structure with a high ratio of positive correlation edges (99.33%), suggesting that positive cooperation was strengthen between different fungi. ( 2 ) FUNGuild analysis indicated that 10 guilds were highly correlated with yam tuber rot. Among these guilds, the relative abundances of dung saprotroph-undefined saprotroph-wood saprotroph and endophyte-plant pathogen were 33.74% and 23.64%, respectively, and the representative genera were Penicillium and Colletotrichum, respectively. Additionally, three guilds were related to both plant pathogen and wood saprotroph, and occupied 13.67% of the ecological functional groups. Moreover, Fusarium was representative genus of all three guilds. Traits analysis showed that some fungi (Penicillium, Fusarium, etc.) in the fungal community were probably invovled in yam tuber rot. ( 3 ) A total of 22 strains were isolated and belonged to 6 genera, including Fusarium ( 9 strains ), Penicillium ( 5 strains ) and Aspergillus ( 4 strains ), etc. This study provides an important reference for understanding the pathogenesis of tuber rot in Dioscorea sp., and for the selection of appropriate pesticides and biocontrol microbes.
Subjects: Biology >> Botany submitted time 2024-06-02 Cooperative journals: 《广西植物》
Abstract： Diospyros dasyphylla Kurz and Diospyros sumatrana Miq. ( Ebenaceae ) are reported as newly recorded species in China. Their diagnostic characters, habitat and distribution of the two newly recorded species are provided. The endangered category of the two newly recorded species is assessed based on field survey. D. dasyphylla closely resembles D. xylocarpa Y. M. Shui, W. H. Chen & Sima, However, it can be distinguished by its young branchlets and leaves, which are densely covered with yellow-brown hairs. Another distinctive feature of D. dasyphylla is its mature fruit, approximately 6 cm in diameter, accompanied by a fruit calyx measuring 8 mm. D. sumatrana is similar to D. elliptifolia Merr., but differs in its white and urceolate corolla, fruit 2 cm in diameter and erected calyx. The voucher specimens are deposited in Herbarium of Guangxi Institute of Botany ( IBK ) and Museum of Beijing Forestry University ( BJFC ). These findings provide new basic data for the biodiversity research of Diospyros plants in China.
Subjects: Biology >> Botany submitted time 2024-06-02 Cooperative journals: 《广西植物》
Abstract： The green leaves, variegated leaves and yellow leaves of Yulania denudata with variegated leaf were used as experimental materials. The anatomical structure and photosynthetic characteristics of three types of leaves were compared from the aspects of photosynthetic pigment content, leaf anatomical structure and light response curve, the factor of photosynthetic characteristics of Y. denudata with variegated leaf was revealed from anatomy. The the result of research as follows: (1) The yellow leaf spots of Y. denudata with variegated leaf is chlorophyll-type leaf spots formed by the decrease of chlorophyll content due to the abnormal structure of chloroplasts. (2) The structure of the thylakoids in the yellow region of the flower and leaf Y. denudata with variegated leaf was abnormal, and ATP synthesis was blocked, which hindered the progress of photosynthesis. (3) The anatomical structure showed that the palisade tissue of the green leaf was developed, the chloroplast integrity and pigment content were higher than that of the variegated leaf and the yellow leaf, and the net photosynthetic rate was higher. (4) There was a significant difference in the maximum net photosynthetic rate and light saturation point between the green leaf and the variegated leaf, and the green leaf can withstand a wider range of bright light than the variegated leaf. This study further elucidates that that the chloroplast structure of Y. denudata with variegated leaf affected its photosynthetic characteristics, and the results provided references for the breeding of fine varieties.
Subjects: Biology >> Botany submitted time 2024-06-02 Cooperative journals: 《广西植物》
Abstract： In order to reveal the albino mechanism of gold-coloured mutant leaves of Cyclobalanopsis gilva, a naturally-occurring leaf-color mutant was used as experimental materials, and the metabolome and transcriptome of mutant leaves and normal green leaves were analyzed by UHPLC-Q Exactive HF-X and high-throughput RNA sequencing, respectively. The results were as follows: ( 1 ) 257 and 357 significantly changed metabolites ( SCMs ) were respectively identified under the positive ion mode and the negative ion mode. Compared with green leaves, the content of some flavonoids such as quercetin, leucoyanidin, myricetin and their derivatives (pyranodelphinin A, isorhamnetin 3-glucuronide, etc. ) increased significantly in mutant leaves, but the content of chlorophylls and carotenoids decreased significantly. ( 2 ) A total of 4 146 differentially expressed genes (DEGs) were detected, of which 1 711 were up-regulated and 2 435 were down-regulated. ( 3 ) KEGG enrichment analysis showed that SCMs and DEGs were mainly enriched in photosynthesis, porphyrin and chlorophyll metabolism and flavonoid biosynthesis. The research results indicate that inhibition of chlorophyll synthesis, chloroplast developmental abnormalities and promotion of flavonoid synthesis were the main factors driving the golden leaf coloration in the mutant C. gilva. In addition, the genes of the MYB and bHLH families were significantly up-regulated in mutant leaves, confirming these two types of transcription factors were involved in regulating flavonoid biosynthesis. This study provided new molecular insights into the phenomenon of leaf etiolation, and also provided reference for exploring leaf color-related functional genes and breeding of landscape plant.
Subjects: Biology >> Botany submitted time 2024-06-02 Cooperative journals: 《广西植物》
Abstract： The stability of phyllosphere microbial community is closely related to plant health. In order to understand the microecological characteristics of tobacco leaves infected with wildfire disease, community structure and diversity of phyllosphere microbiome in diseased spots and healthy tissues of tobacco leaves with different degrees of disease using high-throughput sequencing technology in this paper. The results showed that the dominant microorganisms in diseased and healthy tissues were Proteobacteria and Ascomycota, and their relative abundance in diseased tissues was significantly higher than that in healthy tissues. The dominant genera were Pseudomonas, Pantoea, Alternaria, Plectosphaerella and Conocybe, and only the relative abundance of Pseudomonas in diseased tissues was significantly higher than that in healthy tissues. The diversity and richness of bacterial communities in diseased spots were higher than those in healthy tissues, and the diversity index showed a trend of decreasing and then increasing with the increase of the degree of disease, and the richness index showed a trend of increasing and then decreasing. The richness and diversity index of fungal communities in diseased spots showed a trend of increasing and then decreasing with the increase of the disease degree, and the diversity and richness of fungal communities in diseased spots of mildly and moderately diseased leaves were higher than that in healthy tissues, but the diversity and richness of fungal communities in heavily diseased tissues were lower than those in healthy tissues. Gene functional information and relative abundance of bacteria in diseased spots and healthy tissues are generally similar, primarily related to metabolism, genetic information processing and environmental information processing. The dominant functional taxa of fungi were plant pathogen, animal pathogen-endophyte-plant pathogen-wood saprotroph, undefined saprotroph, wood saprotroph and plant pathogen-wood saprotroph. The results provide a reference for the understanding of evolutionary pattern of tobacco wildfire disease and characterization of the phyllosphere microbial community.
Subjects: Biology >> Botany submitted time 2024-06-02 Cooperative journals: 《广西植物》
Abstract： Bacterial wilt is a devastating soil-borne disease in tomato (Solanum lycopersicum) production. The pathogenic species are complex and tend to have a variation, while mlo caused by the recessive mutation of MLO genes has a broad-spectrum resistance. The previous study suggested that Slmlo1/6 may be involved in the resistance response to bacterial wilt in tomato. In order to further study the gene function of Slmlo1/6 in tomato bacterial wilt resistance, the genetic mutant plants were created by CRISPR/Cas9 technology and their phenotypes were identified followed. The results were as follows: ( 1 ) First, gRNA sequences of SlMLO1/6 were designed and assembled with the U6 promoters, then U6-gRNA1/6 fragments containing highly effective targets were ligated to CRISPR vector of pBGK via restriction enzyme Bsa I digestion, to construct the two-gene fusion knockout vector of pBGK-SlMLO1/6. The recombinant plasmid of pBGK-SlMLO1/6 was transformed into Escherichia coli DH5α competent cells and positive monoclonal clones were selected via plate cultivation. Using Agrobacterium tumefaciens GV3101 strains-mediated genetic transformation and resistance screening to hygromycin, a total of 9 edited tomato plants were obtained with the PCR and sequencing validation. ( 2 ) Target region sequencing showed that M2 and M8 plants had the 177 bp and 7 bp deletion of SlMLO1, respectively, M7 had the 12 bp deletion of SlMLO6, and M9 had a single base T insertion of SlMLO6. Except for 4 single gene homozygous mutants above, the other mutations were heterozygous. ( 3 ) RT-qPCR showed that compared with the wild type plant, SlMLO1/6 gene expression of the mutants was significantly decreased, especially M2, M7, and M8 plants. ( 4 ) Phenotypic identification indicated that SlMLO1/6 may be tomato bacterial wilt susceptibility genes. In a word, the knockout vector is successfully constructed for broad-spectrum resistance MLO genes and tomato transformation is also achieved. Further, a few homozygous gene edited plants acquire resistance to bacterial wilt to some extent. Amino acid deletion and frameshift mutation may be two crucial reasons for the gene function change of Slmlo1/6 in resistance. The results provide a theoretical basis and genetic engineering materials for the gene function study in resistance to bacterial wilt and disease resistance breeding in tomato.
Subjects: Biology >> Botany submitted time 2024-06-02 Cooperative journals: 《广西植物》
Abstract： Wild plants play a pivotal role in people’s daily lives, providing numerous necessities such as food, medicine, and living tools for survival. Zada County, located in the southwestern part of Ngari Prefecture (མངའ་རི, mngav-ri) , Xizang Autonomous Region of China, bordering India, serves as an important gateway for China’s access to South Asia. This region used to engage in prosperous and lively border trade. Characterized by a plateau sub-frigid arid climate, characterized by low annual average temperature, low oxygen concentration, cold winters, and cool summers. The Zang People here has amassed rich traditional knowledge on the utilization of wild plants in adapting to harsh environments. To comprehensively and systematically investigate, document, and study the traditional knowledge of the Zang People in Zada County on the utilization of wild plants, an ethnobotanical investigation methods were adopted. The research involved interviews with 173 informants, recording 3 639 utilization reports (URs), and conducting quantitative analyses using UV, CV, and CII metrics. The results were as follows: (1) The Zang People in Zada County possesses extensive traditional knowledge on the utilization of wild plants, employing 119 species belonging to 40 families and 83 genera. (2) The utilization categories of wild plants in this area are diverse, with 8 utilization categories, and multiple plants possessing two or more uses simultaneously. (3) The most significant plants in people’s lives are Carum carvi (UV=1.220), Artemisia stracheyi (UV=0.919), Rheum acuminatum (UV=0.890), Cupressus sp. (UV=0.769), and Urtica dioica (UV=0.757). Theses plants are intimately connected to the lives of the local Zang People and are deeply loved by them. (4) The intricate and diverse plateau environment significantly influences the utilization of wild plants in this region. This research not only comprehensively and systematically documents the utilization knowledge and characteristics of wild plants in Zada County, but also provides evidence for the further exploration and rational utilization of local plant resources, contributing to the sustainable development of the region. At the same time, it also helps to promote the inheritance and promotion of traditional knowledge, contributing to the prosperity of local culture. In addition, this research has positive implications for biodiversity conservation, helping to raise public awareness and protection consciousness towards biodiversity, and promoting the balance and harmonious development of the ecosystem.
Subjects: Biology >> Botany submitted time 2024-05-15 Cooperative journals: 《干旱区科学》
Abstract： Phyllosphere microorganisms are a crucial component of environmental microorganisms, highly influenced by host characteristics, and play a significant role in plant health and productivity. Nonetheless, the impact of host characteristics on shaping phyllosphere microbial communities of plants with different life forms remains ambiguous. Utilizing high-throughput sequencing technology, this study analyzed the diversity and community composition of phyllosphere epiphytic microorganisms (e.g., bacteria and fungi) of various plant life forms in the hinterland of the Gurbantunggut Desert, Northwest China. Functional annotation of prokaryotic taxa (FAPROTAX) and fungi function guild (FUNGuild) were employed to assess the ecological functions of microorganisms and to investigate the role of stochastic and deterministic processes in shaping phyllosphere microbial communities. Result showed a diverse array of phyllosphere epiphytic microorganisms in the desert plants, with Proteobacteria, Cyanobacteria, and Actinobacteriota dominating bacterial community, while Ascomycota and Basidiomycota were prevalent in fungal community. Comparison across different plant life forms highlighted distinct microbial communities, indicating strong filtering effects by plant characteristics. FAPROTAX prediction identified intracellular parasites (accounting for 27.44% of bacterial community abundance), chemoheterotrophy (10.12%), and phototrophy (17.41%) as the main functions of epiphytic bacteria on leaves of different life form plants. FUNGuild prediction indicated that phyllosphere epiphytic fungi primarily served as Saprotrophs (81.77%), Pathotrophs (17.41%), and Symbiotrophs (0.82%). Co-occurrence network analysis demonstrated a predominance of positive correlations among different microbial taxa. Raup-Crick dissimilarity index analysis revealed that deterministic processes predominantly influenced phyllosphere bacterial and fungal community assembly. Variance partitioning analysis and random forest modeling suggested that plant leaf functional traits significantly impacted both bacterial and fungal community composition, with fungal community composition showing a closer association with leaf nutrients and physiology compared with bacterial community composition. The distinct responses of bacterial and fungal communities to plant traits were attributed to the differing properties of bacteria and fungi, such as bacteria having higher potential dispersal rates and broader ecological niches than fungi. Overall, the results indicate that phyllosphere bacterial and fungal communities undergo similar community assembly processes, with fungi being more influenced by plant characteristics than bacteria. These findings offer novel insights into the ecology of phyllosphere microbial communities of desert plants.
Subjects: Biology >> Botany submitted time 2024-04-15 Cooperative journals: 《干旱区科学》
Abstract： Vegetation restoration and reconstruction are effective approaches to desertification control and achieving social and economic sustainability in desert areas. However, the self-succession ability of native plants during the later periods of vegetation restoration remains unclear. Therefore, this study was conducted to bridge the knowledge gap by investigating the regeneration dynamics of artificial forest under natural conditions. The information of seed rain and soil seed bank was collected and quantified from an artificial Caragana korshinskii Kom. forest in the Tengger Desert, China. The germination tests were conducted in a laboratory setting. The analysis of species quantity and diversity in seed rain and soil seed bank was conducted to assess the impact of different durations of sand fixation (60, 40, and 20 a) on the progress of vegetation restoration and ecological conditions in artificial C. korshinskii forest. The results showed that the top three dominant plant species in seed rain were Echinops gmelinii Turcz., Eragrostis minor Host., and Agropyron mongolicum Keng., and the top three dominant plant species in soil seed bank were E. minor, Chloris virgata Sw., and E. gmelinii. As restoration period increased, the density of seed rain and soil seed bank increased first and then decreased. While for species richness, as restoration period increased, it gradually increased in seed rain but decreased in soil seed bank. There was a positive correlation between seed rain density and soil seed bank density among all the three restoration periods. The species similarity between seed rain or soil seed bank and aboveground vegetation decreased with the extension of restoration period. The shape of the seeds, specifically those with external appendages such as spines and crown hair, clearly had an effect on their dispersal, then resulting in lower seed density in soil seed bank. In addition, precipitation was a crucial factor in promoting rapid germination, also resulting in lower seed density in soil seed bank. Our findings provide valuable insights for guiding future interventions during the later periods of artificial C. korshinskii forest, such as sowing and restoration efforts using unmanned aerial vehicles.
Subjects: Biology >> Botany submitted time 2024-04-15 Cooperative journals: 《干旱区科学》
Abstract： The maintenance of sand-fixing vegetation is important for the stability of artificial sand-fixing systems in which seed dispersal plays a key role. Based on field wind tunnel experiments using 11 common plant species on the southeastern edge of the Tengger Desert, China, we studied the secondary seed dispersal in the fixed and semi-fixed sand dunes as well as in the mobile dunes in order to understand the limitations of vegetation regeneration and the maintenance of its stability. Our results indicated that there were significant variations among the selected 11 plant species in the threshold of wind speed (TWS). The TWS of Caragana korshinskii was the highest among the 11 plant species, whereas that of Echinops gmelinii was the lowest. Seed morphological traits and underlying surface could generally explain the TWS. During the secondary seed dispersal processes, the proportions of seeds that did not disperse (no dispersal) and only dispersed over short distance (short-distance dispersal within the wind tunnel test section) were significantly higher than those of seeds that were buried (including lost seeds) and dispersed over long distance (long-distance dispersal beyond the wind tunnel test section). Compared with other habitats, the mobile dunes were the most difficult places for secondary seed dispersal. Buried seeds were the easiest to be found in the semi-fixed sand dunes, whereas fixed sand dunes were the best sites for seeds that dispersed over long distance. The results of linear mixed models showed that after controlling the dispersal distance, smaller and rounder seeds dispersed farther. Shape index and wind speed were the two significant influencing factors on the burial of seeds. The explanatory power of wind speed, underlying surface, and seed morphological traits on the seeds that did not disperse and dispersed over short distance was far greater than that on the seeds that were buried and dispersed over long distance, implying that the processes and mechanisms of burial and long-distance dispersal are more complex. In summary, most seeds in the study area either did not move, were buried, or dispersed over short distance, promoting local vegetation regeneration.
Subjects: Biology >> Botany submitted time 2024-01-12 Cooperative journals: 《干旱区科学》
Abstract： Wolfberry (Lycium barbarum L.) is important for health care and ecological protection. However, it faces problems of low productivity and resource utilization during planting. Exploring reasonable models for water and nitrogen management is important for solving these problems. Based on field trials in 2021 and 2022, this study analyzed the effects of controlling soil water and nitrogen application levels on wolfberry height, stem diameter, crown width, yield, and water (WUE) and nitrogen use efficiency (NUE). The upper and lower limits of soil water were controlled by the percentage of soil water content to field water capacity (θf), and four water levels, i.e., adequate irrigation (W0, 75%–85% θf), mild water deficit (W1, 65%–75% θf), moderate water deficit (W2, 55%–65% θf), and severe water deficit (W3, 45%–55% θf) were used, and three nitrogen application levels, i.e., no nitrogen (N0, 0 kg/hm2), low nitrogen (N1, 150 kg/hm2), medium nitrogen (N2, 300 kg/hm2), and high nitrogen (N3, 450 kg/hm2) were implied. The results showed that irrigation and nitrogen application significantly affected plant height, stem diameter, and crown width of wolfberry at different growth stages (P<0.01), and their maximum values were observed in W1N2, W0N2, and W1N3 treatments. Dry weight per plant and yield of wolfberry first increased and then decreased with increasing nitrogen application under the same water treatment. Dry weight per hundred grains and dry weight percentage increased with increasing nitrogen application under W0 treatment. However, under other water treatments, the values first increased and then decreased with increasing nitrogen application. Yield and its component of wolfberry first increased and then decreased as water deficit increased under the same nitrogen treatment. Irrigation water use efficiency (IWUE, 8.46 kg/(hm2•mm)), WUE (6.83 kg/(hm2•mm)), partial factor productivity of nitrogen (PFPN, 2.56 kg/kg), and NUE (14.29 kg/kg) reached their highest values in W2N2, W1N2, W1N2, and W1N1 treatments. Results of principal component analysis (PCA) showed that yield, WUE, and NUE were better in W1N2 treatment, making it a suitable water and nitrogen management mode for the irrigation area of the Yellow River in the Gansu Province, China and similar planting areas.
Subjects: Biology >> Botany Subjects: Biology >> Microbiology submitted time 2023-11-17
Abstract： Drought is one of the most serious abiotic stresses which also shifts the composition of root associated microbiomes. However, there is a lack of genetic evidence regarding whether and how plant genetic effects positively reshape drought induced microbiome changes. Root hairs play essential roles in water uptaking, but whether root hairs also orchestrate microbiome re-shaping process during drought stress is unknown. By utilizing genetic mutants with enhanced or decreased root hair densities, we detected a significant effect of plant genetic effect on drought induced microbiome changes. In addition, the hairy mutant (gl2) triggers a deterministic process during drought induced microbiome re-assembly, which further confirms the involvement of host effects in re-shaping drought induced microbiome changes. Rhizobiaceae strains were detected as key biomarker species positively correlated with root hair densities. Moreover, the gl2 mutant also shapes more complex microbiome co-occurrence networks, with more Rhizobiaceae hubs. Our findings unveil the novel roles of root hairs in shaping microbiome structure and network interactions upon drought stress, particularly through regulating the abundance and network centrality of Rhizobiaceae strains. Root hair related mutants also broadly affect root metabolome upon drought stress. Understanding the physiological and microbial ecological basis of host mediated microbiome re-shaping under drought helps develop microbiome engineering approaches to combat climate changes.
Peer Review Status:Awaiting Review
Subjects: Biology >> Botany submitted time 2023-11-13 Cooperative journals: 《干旱区科学》
Abstract： Endophytes, as crucial components of plant microbial communities, significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts, promote plant growth, and degrade pathogenic fungal mycelia. In this study, an experiment was conducted in August 2022 to explore the growth-promoting potential of endophytic bacterial strains isolated from two medical plant species, Thymus altaicus and Salvia deserta, using a series of screening media. Plant samples of Thymus altaicus and Salvia deserta were collected from Zhaosu County and Habahe County in Xinjiang Uygur Autonomous Region, China, in July 2021. Additionally, the inhibitory effects of endophytic bacterial strains on the four pathogenic fungi (Fusarium oxysporum, Fulvia fulva, Alternaria solani, and Valsa mali) were determined through the plate confrontation method. A total of 80 endophytic bacterial strains were isolated from Thymus altaicus, while a total of 60 endophytic bacterial strains were isolated from Salvia deserta. The endophytic bacterial strains from both Thymus altaicus and Salvia deserta exhibited plant growth-promoting properties. Specifically, the strains of Bacillus sp. TR002, Bacillus sp. TR005, Microbacterium sp. TSB5, and Rhodococcus sp. TR013 demonstrated strong cellulase-producing activity, siderophore-producing activity, phosphate solubilization activity, and nitrogen-fixing activity, respectively. Out of 140 endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta, 104 strains displayed anti-fungal activity against Fulvia fulva, Alternaria solani, Fusarium oxysporum, and Valsa mali. Furthermore, the strains of Bacillus sp. TR005, Bacillus sp. TS003, and Bacillus sp. TSB7 exhibited robust inhibition rates against all the four pathogenic fungi. In conclusion, the endophytic bacterial strains from Thymus altaicus and Salvia deserta possess both plant growth-promoting and anti-fungal properties, making them promising candidates for future development as growth-promoting agents and biocontrol tools for plant diseases.
Subjects: Biology >> Botany Subjects: Biology >> Biochemistry submitted time 2023-10-23
Abstract： The protein-protein interactions (PPIs) have a pivotal role in plant cells. There are numerous methods, in vivo or in vitro, have been developed to investigate the PPIs. The yeast mating-based Split-Ubiquitin System (mbSUS) is an alternative method of classic yeast-two-hybrid (Y2H) method. The mbSUS assay is not only as fast and inexpensive as the Y2H method, but also suitable for membrane proteins investigation with lower false positive rate. The recently improved mbSUS assay is suitable for the determination of PPIs among membrane proteins and soluble proteins, and successful used for detecting the interaction between ion channels and vesicle traffic proteins. Here, we describe the principles, protocols and experiment notes for mbSUS assay, providing an alternative method for PPI research in plants.
Peer Review Status:Awaiting Review
Subjects: Biology >> Botany submitted time 2023-10-17 Cooperative journals: 《干旱区科学》
Abstract：Tiger nut is a bioenergy crop planted in arid areas of northern China to supply oil and adjust the planting structure. However, in the western region of Inner Mongolia Autonomous Region, China, less water resources have resulted in a scarcity of available farmland, which has posed a huge obstacle to planting tiger nut. Cultivation of tiger nut on marginal land can effectively solve this problem. To fully unlock the production potential of tiger nut on marginal land, it is crucial for managers to have comprehensive information on the adaptive mechanism and nutrient requirement of tiger nut in different growth periods. This study aims to explore these key information from the perspective of nutrient coordination strategy of tiger nut in different growth periods and their relationship with rhizosphere soil nutrients. Three fertilization treatments including no fertilization (N:P (nitrogen:phosphorous)=0:0), traditional fertilization (N:P=15:15), and additional N fertilizer (N:P=60:15)) were implemented on marginal land in the Dengkou County. Plant and soil samples were collected in three growth periods, including stolon tillering period, tuber expanding period, and tuber mature period. Under no fertilization, there was a significant correlation between N and P contents of tiger nut roots and tubers and the same nutrients in the rhizosphere soil (P<0.05). Carbon (C), N, and P contents of roots were significantly higher than those of leaves (P<0.05), and the C:N ratio of all organs was higher than those under other treatments before tuber maturity (P<0.05). Under traditional fertilization, there was a significant impact on the P content of tiger nut tubers (P<0.05). Under additional N fertilizer, the accumulation rate of N and P was faster in stolons than in tubers (P<0.05) with lower N:P ratio in stolons during the tuber expansion period (P<0.05), but higher N:P ratio in tubers (P<0.05). The limited availability of nutrients in the rhizosphere soil prompts tiger nut to increase the C:N ratio, improving N utilization efficiency, and maintaining N:P ratio in tubers. Elevated N levels in the rhizosphere soil decrease the C:N ratio of tiger nut organs and N:P ratio in stolons, promoting rapid stolon growth and shoot production. Supplementary P is necessary during tuber expansion, while a higher proportion of N in fertilizers is crucial for the aboveground biomass production of tiger nut.
Subjects: Biology >> Botany submitted time 2023-10-17 Cooperative journals: 《干旱区科学》
Abstract：Root pullout performance of plants is an important mechanical basis for soil reinforcement by plant roots in the semi-arid areas. Studies have shown that it is affected by plant factors (species, ages, root geometry, etc.) and soil factors (soil types, soil moisture, soil bulk densities, etc.). However, the effects of loading rates on root pullout performance are not well studied. To explore the mechanical interactions under different loading rates, we conducted pullout tests on Medicago sativa L. and Hippophae rhamnoides L. roots under five loading rates, i.e., 5, 50, 100, 150, and 200 mm/min. In addition, tensile tests were conducted on the roots in diameters of 0.52.0 mm to compare the relationship between root tensile properties and root pullout properties. Results showed that two root failure modes, slippage and breakage, were observed during root pullout tests. All M. sativa roots were pulled out, while 72.2% of H. rhamnoides roots were broken. The maximum fracture diameter and fracture root length of H. rhamnoides were 1.22 mm and 7.44 cm under 100 mm/min loading rate, respectively. Root displacement values were 4.63% (0.43%) and 8.91% (0.52%) of the total root length for M. sativa and H. rhamnoides, respectively. The values of maximum pullout force were 14.6 (0.7) and 17.7 (1.8) N under 100 mm/min for M. sativa and H. rhamnoides, respectively. Values of the maximum pullout strength for M. sativa and H. rhamnoides were 38.38 (5.48) MPa under 150 mm/min and 12.47 (1.43) MPa under 100 mm/min, respectively. Root-soil friction coefficient under 100 mm/min was significantly larger than those under other loading rates for both the two species. Values of the maximum root pullout energy for M. sativa and H. rhamnoides were 87.83 (21.55) mmN under 100 mm/min and 173.53 (38.53) mmN under 200 mm/min, respectively. Root pullout force was significantly related to root diameter (P0.05). Root pullout strength was greater than root tensile strength for the two species. The results suggested that there was no need to deliberately control loading rate in root pullout tests in the semi-arid soil, and root pullout force and pullout strength could be better parameters for root reinforcement model compared with root tensile strength as root pullout force and pullout strength could more realistically reflect the working state of roots in the semi-arid soil.
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