Search Results (53)

Ammopiptanthus mongolicus is a relict species from the ancient Mediterranean of the Tertiary period and the only strong xerophytic evergreen broad-leaved shrub in the central Asian desert. Foliar endophytic and epiphytic bacteria jointly form phyllosphere microorganisms that influence plant health. This study investigated the dynamic changes in foliar endophytic bacterial communities across four leaf growth stages (Young, Mature, Old1, and Old2). Illumina 16S region (V5–V7) amplicon sequencing was used to analyze community composition, function, construction process, and environmental driving factors. The Old1 and Old2 stages were clearly separated from the Young and Mature stages, which demonstrated closer clustering. Community diversity and evenness first increased from the Young to Mature stages, declined at the Old1 stage, and finally reached maximum values at the Old2 stage; richness increased gradually. Total amplicon sequence variant (ASV) numbers, stage-specific ASVs, and their proportion increased with leaf development, whereas the proportion of shared ASVs between adjacent, interval, and all stages decreased. Dominant genera were Rhodococcus (Young), unclassified_f__Comamonadaceae (Mature), Rhodococcus (Old1), and Bacillus (Old2). Co-occurrence networks became progressively simpler, with reduced inter-node and positive connectivity. Functional predictions revealed that chemoheterotrophy and aerobic chemoheterotrophy decreased initially and then increased, with the lowest values at Old1. N, C/P, N/P, and SOD reached maximum at the Old2 stage. P was maximum at the Mature stage. P, C/P, and N/P were significantly positively correlated with the Young stage, N with the Mature stage, and SOD with the Old2 stage (p < 0.05). These findings enhance understanding of the diversity, composition, function, and plant–endophyte relationships in xerophytic relict species, particularly evergreen desert shrubs. Full article

Understanding how cultivated xerophytic shrubs physiologically regulate canopy water loss under anomalously wet conditions is crucial for predicting ecohydrological responses and for providing practical guidance in landscape restoration under the ongoing warming–wetting trend on the northern Loess Plateau. This study tested hypotheses concerning the hierarchy of atmospheric and soil-water controls on canopy transpiration (E_c), stomatal conductance (g_s), the strength of canopy–atmosphere coupling, and species-specific soil-water sensitivities and water-use strategies in Caragana korshinskii and Salix psammophila. Concurrent measurements of branch-level sap flow, meteorological variables, and soil water content (SWC) at multiple depths were conducted in two adjacent stands during the wet season of a climatically wet year (July–September 2017). Meteorological factors, particularly vapor pressure deficit (VPD), were the dominant drivers of daily E_c and g_s, whereas SWC exerted secondary but species-specific influences. Both shrubs were strongly coupled to the atmosphere, with consistently low decoupling coefficients (Ω ≈ 0.11–0.15) on daily scales. C. korshinskii maintained stable water use through access to deeper soil, whereas S. psammophila responded sensitively to fluctuations in shallow SWC. These contrasting patterns indicate depth-partitioned water-use strategies and a context-dependent continuum between isohydric and anisohydric behavior rather than fixed species traits. The findings support improved parameterization of shrub water use in ecohydrological models, more effective water-use management, and informed species selection and nursery practices for landscape restoration in semi-arid regions experiencing warming–wetting climatic shifts. Full article

Climate change and global warming are deeply impacting natural foraging dependent upon rain fall. To understand how xerophytes cope with these dramatic changes, comparative transcriptomic profiling of Atriplex halimus and Atriplex leucoclada was investigated under drought stress. The data revealed both shared and species-specific adaptive mechanisms. Differentially expressed genes (DEGs) clustered into major conserved gene families, including stress signaling, transcriptional regulation, antioxidant defense, metabolism, transport, and hormone signaling. In A. halimus, drought tolerance was characterized by strong transcriptional regulation, redox balance, and energy homeostasis, highlighted by the up-regulation of WRKY, MYB, and SET-domain transcription factors, calcium transporters, SnRK1 kinases, and stress-protective proteins such as HSPs and LEAs. On the other hand, A. leucoclada exhibited broader signaling flexibility and structural reinforcement through enrichment of MAPKs, CDPKs, 14-3-3 proteins, and cell wall-modifying enzymes (XTHs, expansins, chitinase-like proteins), as well as high expression of transporters and hormone-responsive genes. Such patterns indicated distinct drought adaptation strategies: A. halimus relied on rapid transcriptional and redox adjustments suited for fluctuating moisture regimes, while A. leucoclada employed multi-layered, constitutive defenses for persistent arid conditions. Together, these results elucidate complementary molecular strategies enabling ecological divergence and drought resilience among closely related halophytes. Full article

The xerophyte medicinal species Crithmum maritimum was investigated for its physiological and antioxidant responses under increasing salinity stress and foliar biostimulant application. At moderate salinity (10 dS/m sodium chloride NaCl), plant growth and photosynthetic activity were enhanced, whereas high salinity (20 dS/m) led to significant reductions in biomass, photosynthetic efficiency, and water use efficiency. Salinity-induced oxidative stress was confirmed by elevated levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), in upper plant tissues. Foliar application of two bioactive compounds—Aquamin and Cultisano—partially mitigated the detrimental effects of high salinity. Treated plants maintained higher photosynthetic parameters and exhibited improved antioxidant profile compared to untreated controls. Furthermore, GC–MS analysis of essential oils revealed that salinity altered the composition of key volatile components, notably increasing γ-terpinene and reducing p-cymene content. Biostimulant treatments counteracted these changes, enhancing terpene components such as p-cymene, and thymol-methyl-ether. Overall, the findings highlight the potential of biostimulants to enhance both salt tolerance as well as the phytochemical value of C. maritimum, suggesting promising applications in sustainable agriculture and high-value plant product development under saline conditions. It was concluded that the type of biostimulant significantly influenced the physiological and quality characteristics of sea fennel plants. Further study on this topic is proposed, aiming at the improvement of antioxidant activity, which is beneficial to human health. Full article

Global climate change has intensified land desertification in the arid and semi-arid regions of northwestern China, highlighting the urgent need to cultivate plant species with ideal architecture and well-developed root systems to combat ecosystem degradation. Amorpha fruticosa is widely used as a windbreak and sand-fixation shrub; however, its rapid growth and high transpiration during the early planting stage often result in excessive water loss, low survival rates, and limited vegetation restoration effectiveness. Plant growth retardants (PGRts) are known to suppress apical dominance and promote branching. In this study, one-year-old A. fruticosa seedlings were treated with different combinations of paclobutrazol (PP₃₃₃) and uniconazole (S₃₃₀₇) to investigate their effects on plant morphology and biomass allocation; it aims to determine the optimal formula for cultivating shrub structures with excellent windbreak and sand-fixation effects in land desertification areas. The results showed that both PP₃₃₃ and S₃₃₀₇ significantly inhibited plant height while promoting basal stem diameter, branching, and root development. Among all treatments, the S₃₃₀₇ 200 mg·L⁻¹ + PP₃₃₃ 200 mg·L⁻¹ combination (SD3) was the most effective, resulting in the greatest increases in basal diameter, branch number, total root length, and root-to-shoot ratio, while significantly reducing height increment, leaf length and leaf area (p < 0.05). Under the S₃₃₀₇ 200 mg·L⁻¹ + PP₃₃₃ 300 mg·L⁻¹ treatment (SD4), leaf width and specific leaf area were reduced by 17.92% and 38.89%, respectively, compared with the control. Correlation analysis revealed significant positive or negative relationships among most growth traits, with leaf length negatively correlated with other morphological indicators. Fresh and dry weights of both aboveground and root tissues were significantly positively correlated with basal diameter (R = 0.38) and branch basal diameter (R = 0.33). Principal component analysis demonstrated that the SD3 treatment achieved the highest comprehensive score (2.91), indicating its superiority in promoting a compact yet robust plant architecture. Overall, the SD3 treatment improved drought resistance and sand-fixation capacity of A. fruticosa by “dwarfing and strengthening plants while optimizing root–shoot allocation.” These findings provide theoretical support for large-scale cultivation and vegetation restoration in arid and semi-arid regions and offer a technical reference for growth regulation and windbreak and sand-fixation capacity in other xerophytic shrub species. Full article

Plants inhabiting arid regions often harbor microbial communities that contribute to their resilience under extreme conditions. Yet, the genomic diversity and functional potential of bacterial endophytes associated with desert-adapted plants, particularly in Africa, remain largely unexplored. In this study, we investigated Microbacterium endophytes from the xerophytic cucurbit Citrullus colocynthis L. (Cucurbitaceae), collected in a semi-arid environment in central Morocco. Using culture-based isolation, phenotypic characterization, and whole-genome sequencing, we analyzed three representative isolates from leaf and root tissues. Genome-based taxonomy combined with polyphasic analyses identified two novel species, Microbacterium xerophyticum sp. nov. and Microbacterium umsixpiens sp. nov., with genome sizes of approximately 4.0 Mb and 3.9 Mb, respectively. Functional annotation revealed traits consistent with endophytism in water-limited ecosystems, including oxidative and osmotic stress responses, metal homeostasis, and high-affinity phosphate uptake. Differences in siderophore acquisition and nitrogen metabolism suggest niche partitioning between the two species. These findings document two novel bacterial species from a medicinal plant native to arid ecosystems, broaden the known diversity of plant-associated Microbacterium, and provide region-specific genomic references with adaptive traits relevant to host resilience under arid conditions. Full article

Background: As a typical xerophyte, H. halodendron can not only grow in desert sandy areas but also serves as an excellent nectar source and ornamental plant. However, research on its molecular and physiological mechanisms underlying drought tolerance remains limited. Methods: This study systematically investigated its drought resistance characteristics by integrating physiological parameters and Illumina transcriptome sequencing, and further validated key genes involved in the drought resistance mechanisms. Results: A total of 46,305 functional genes were identified, among which 6561 were differentially expressed genes (DEGs). These DEGs were significantly enriched in chloroplast function, photosynthesis, proline biosynthesis, and peroxidase activity. Under drought stress, the net photosynthetic rate, stomatal conductance, chlorophyll content, and transpiration rate decreased. Under severe drought conditions, only 5 out of 80 photosynthesis-related DEGs were up-regulated, while the rest were down-regulated, indicating that reduced chlorophyll content impaired light absorption, carbon reactions, and photosynthetic efficiency. Additionally, the contents of proline, soluble sugars, and soluble proteins, as well as the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), increased. The identification of 35 osmotic regulation-related and 39 antioxidant enzyme-related DEGs suggests that H. halodendron enhances osmotic adjustment substance synthesis and reactive oxygen species (ROS) scavenging capacity to counteract osmotic stress. Conclusions: Physiological, biochemical and gene expression analyses under drought stress provide a basis for the study of the drought tolerance characteristics of H. halodendron, which is of great significance for ecological environment governance using H. halodendron. Full article

Desert ecosystems pose extreme challenges to plant survival. This study explores the adaptive strategies of two xerophytic halophytes, Alhagi sparsifolia and Nitraria roborowskii, in Xinjiang’s Ebinur Lake wetland, focusing on their plant–soil–microbe (PSM) coupling systems across desert gradients. Results revealed significant interspecific and gradient-dependent differences in plant functional traits: A. sparsifolia showed high growth plasticity with a fast-growth strategy, while N. roborowskii adopted a conservative strategy. Rhizosphere soil physicochemical properties and microbial community structure exhibited strong spatial heterogeneity and host specificity, with N. roborowskii having a more complex microbial network and A. sparsifolia showing higher modularity. Multivariate factor analysis elucidated couplings among plant traits, soil properties, enzymes, and microbes. The two species form distinct interaction systems adapted to desert saline–alkali stress, advancing the understanding of ecological adaptation and informing restoration. Full article

The present study investigates the antimicrobial, antioxidant, and in vitro antidiabetic potential of cold infusions prepared from different parts of the Greek carob tree (Ceratonia siliqua L.), which is a xerophytic species. Carob samples, including green and ripe pods and leaves, were collected from an urban area of Attica, Greece, and extracted using food-grade solvents (water and a water–ethanol mixture, 90:10, v/v). The extracts were evaluated for antibacterial activity against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 6538 using automated turbidometry. In addition, total phenolic content and antioxidant and antiradical activities were determined via spectrophotometry; the phenolic profile was analyzed using liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-QToF-MS), and α-amylase inhibitory activity was assessed through an in vitro assay. All extracts exhibited statistically significant (p < 0.05) bacteriostatic effects, with green pods and leaves showing the highest activity. Ripe pods demonstrated the most potent α-amylase inhibition (up to 96.43%), especially when extracted with water–ethanol mixture (90:10, v/v). Liquid chromatography coupled with tandem quadrupole/time-of-flight mass spectrometry (LC-QToF-MS) analysis revealed a rich phenolic profile across all samples. While carob leaves showed no α-amylase inhibition, their phenolic profile suggests other potential health-related bioactivities. These findings support the development of carob-based functional food products and highlight the nutritional and pharmaceutical potential of this resilient Mediterranean crop. Full article

This paper shows the results of a study on the ecological structure and spatial distribution of communities of the protected steppe ground beetle Carabus hungaricus Fabricius, 1792 (Coleoptera: Carabidae), in Bulgaria. It also points some phenological data and details about the species activity. In the period May 2021–December 2023, we explored 42 sample plots in xerophytic landscapes in central–western Bulgaria, representing the southernmost limits of the steppe fauna in Eurasia. With 252 pitfall traps, 69,903 effective trap-days were realised, and 15,333 carabid individuals from 184 species were identified. Carabus hungaricus was established in seven sites (frequency of occurrence, F = 16.7%), with a total of 198 specimens (1.3% of all carabids and almost 4% of the total dynamic density). In these seven sites, we found 57 species, mostly open habitat dwellers. The tribe Harpalini had 33% of the species. The most species-rich genera were Harpalus (13 species), Amara (8) and Carabus (6). Calathus distinguendus was superdominant with more than 71% of all carabid specimens. Euconstant species, collected in all seven sites (F = 100%), were Carabus coriaceus and Calathus distinguendus. The two classes of life forms had almost equal proportions, 28 (49.1%) Zoophagous and 29 (50.9%) Mixophytophagous species, which is extraordinary for Bulgaria, but typical for the Eurasian steppe zone. Macropterous beetles comprised 56% of the species and brachypterous were 25%, which is comparable only with typical montane habitats. Concerning humidity preferences, mesoxerophilous carabids predominated (25 species, 44%). In relation to its ground beetle fauna, the studied complex of habitats is quite remarkable for Bulgaria and appears to be stable and characteristic for the steppe biome. Full article

Moroccan vegetation faces significant pressure particularly from human activities and climate change, while most ecosystems lack detailed assessments. Phytoecological studies and species assessments are implemented using vegetation sampling, analysis of climate data, geological substrate maps, and the Digital Elevation Model (DEM). The study area hosts 565 plant species distributed into 74 families, with Asteraceae being the most abundant family, representing 17.7%. In addition, the correspondence analysis test demonstrates that species are grouped into six distinct blocks. Block 1 comprises a set of Quercus ilex forests. Block 2 encompasses Juniperus phoenicea lands and transition zones between Quercus ilex and Juniperus phoenicea. Block 3 represents Pinus halepensis forests and pine occurrences within Quercus ilex and Juniperus phoenicea stands. Block 4 indicates the emergence of xerophytic species alongside the aforementioned species; it forms the upper limits of Blocks 1, 2, and 3. Block 5 corresponds to formations dominated by Juniperus thurifera in association with xerophytes. Block 6 groups together a set of xerophytic species characteristic of high mountain environments. Additionally, Quercus ilex colonizes the subhumid zones and prefers limestone substrates, Juniperus phoenicea and Tetraclinis articulata, and Pinus halepensis occupies the hot part of the semi-arid in limestone, clays, and conglomerates, while the Juniperus thurifera and xerophytes inhabit the cold parts and limestone substrates. The thermo-Mediterranean vegetation level occupies low altitudes, dominated by Tetraclinis articulata, Juniperus phoenicea, and Olea europaea. The meso-Mediterranean level extends to intermediate altitudes, dominated by Quercus ilex and Juniperus phoenicea. While the supra-Mediterranean level is dominated by Quercus ilex, Arbutus unedo, and Cistus creticus. The mountain Mediterranean level, located in the high mountains, is dominated by Juniperus thurifera associated with xerophytes. Finally, the oro-Mediterranean level, found at extreme altitudes, is dominated by xerophytes. Some species within this region are endemic, rare, and threatened. Consequently, the implementation of effective conservation and protection policies is recommended. Full article

This study investigates the anatomical adaptations and ecological plasticity of C. ambiguus in extreme environmental conditions by analyzing the structural characteristics of its leaves and annual shoots collected from 12 populations in the arid regions of Mangystau, including Western Karatau, Northern Aktau, and the Tyubkaragan Peninsula. Microscopic and statistical analyses revealed significant variability in key anatomical traits, including epidermal thickness, collenchyma, primary cortex, and vascular bundle area, highlighting the species’ adaptive responses to drought, high solar radiation, and limited water availability. The epidermal thickness ranged from 14.85 µm (Pop_12 Botakan) to 22.51 µm (Pop_6 Samal), demonstrating xeromorphic adaptations for reducing transpiration. At the same time, the vascular bundle area varied from 286.06 × 10⁻³ mm² (Pop_3 Emdikorgan) to 528.51 × 10⁻³ mm² (Samal), indicating differences in water transport efficiency across populations. Despite substantial anatomical variation, the low coefficients of variation (0.31%–6.31%) suggested structural stability, reinforcing C. ambigua’s ability to maintain functional integrity under environmental stress. Canonical Correlation Analysis (CCA) confirmed that environmental factors such as soil type, elevation, and water availability significantly influenced anatomical traits. Floristic analysis revealed distinct patterns of species richness, with the highest diversity recorded in Pop_4 and Pop_7, while Pop_12 and Pop_9 exhibited lower diversity, indicating potential vulnerability. Furthermore, the identified anatomical traits could serve as key markers for selecting drought-resistant genotypes in afforestation and restoration programs. This study also highlighted the need for the long-term monitoring of C. ambigua populations to assess the impact of climate change on structural adaptations. These findings offer a framework for integrating ecological and genetic studies to refine conservation strategies for xerophytic species. Full article

Haloxylon ammodendron plays a pivotal role in combating aeolian desertification and restoring degraded arid ecosystems. Strategic afforestation protocols for this xerophytic species offer dual benefits in ecological stabilization and socioeconomic development, particularly in ecotonal zones between desert and oasis ecosystems, as exemplified by the Jilantai Salt Lake region. This investigation employs allometric scaling analysis to elucidate biomass allocation strategies in H. ammodendron plantations under three distinct silvicultural approaches: soil moisture retention afforestation, water flushing afforestation, and mechanical hole afforestation. Key findings demonstrate that water flushing afforestation treatment induced significant biomass enhancement (total biomass: 1718.69 ± 214.28 g), with phylloclade (photosynthetic branch) and vegetative organ biomass increasing by 29.03% and 60.34%, respectively, compared to conventional methods. Conversely, soil moisture retention afforestation preferentially promoted lignification processes, maximizing biomass allocation to structural components (stems: 15.2% increase) and reproductive structures (inflorescences: 22.7% elevation). Standardized major axis regression revealed differential scaling exponents among organ pairs under varying treatments (stem-phylloclade: 1.798; inflorescence-phylloclade: 1.752; vegetative-reproductive: 1.672; p < 0.001), indicating treatment-specific allometric allocation patterns. Notably, soil moisture retention afforestation induced lateral crown expansion through enhanced meristematic activity in secondary branches (p < 0.01), contrasting with the apical dominance observed in water flushing afforestation and mechanical hole afforestation specimens. These morphological divergences suggest resource allocation trade-offs between vertical exploration and horizontal exploitation strategies. The differential growth trajectories were strongly correlated with edaphic moisture redistribution patterns (R² = 0.83, p < 0.001), as quantified using soil water potential measurements. This study provides mechanistic insights into phenotypic plasticity responses to silvicultural interventions. These findings advance our understanding of allometric growth regulation in a psammophyte and establish an empirical basis for optimizing desert afforestation strategies in arid transitional ecotones. Full article

Riparian zones, acting as transitional areas between aquatic and terrestrial ecosystems, boast a rich diversity of plant species. However, alterations in river hydrological regimes can significantly impact plant growth and distribution. In this study, seven typical reaches of Yongding River Basin were selected, and xylem water, soil water at different depths, and river water were collected in May and August. By measuring δ²H and δ¹⁸O values and combining with MixSIAR model, the proportion of water utilization by plants from different sources was quantified. The findings revealed that δ²H and δ¹⁸O values of river water, soil water, and plant xylem water were higher in August compared to May. While there was no significant difference in δ²H and δ¹⁸O values between river and soil water during different periods (p > 0.05), significant differences were observed in δ¹⁸O in plant xylem water (p = 0.022). Regardless of whether it was May or August, herbaceous plants utilized river water more extensively than trees and shrubs, and hydrophytes exhibited a higher dependence on river water compared to mesophytes and xerophytes. Some hygrophytes (P. anserina, etc.) utilized river water for over 90% of their total water intake. There were significant differences between herbs and trees and shrubs in the proportion of river water usage in August (p = 0.001). Moreover, considerable variations existed in the proportion of river water usage among different water ecotypes in both May (p = 0.005) and August (p < 0.001). Our findings provide a scientific basis for the rational allocation of plants in the process of riparian vegetation restoration. Full article

Pollen rain studies are rare in arid and semi-arid regions worldwide. Interpretations related to the dynamics of plant communities and possible paleoclimatic changes in these areas face significant limitations due to this lack of data. The global biome of Seasonally Dry Tropical Forests and Shrublands (SDTFS) is represented in Northeast Brazil by the caatinga, which is composed of xerophytic vegetation. This study aimed to generate information about the pollen rain in this area and to understand its relationship with species flowering, pollination syndromes, life forms, and climatic aspects. A caatinga area in Canudos, Bahia, Brazil (09°54′ S 39°07′ W), was selected for this purpose. Artificial pollen collectors were installed and exchanged monthly over two years for palynological analyses of the collected material, using standard palynological techniques. A total of 124 pollen types were identified, with approximately 8823 pollen grains deposited per cm² over the two years. Several vegetation components were represented in the pollen rain, reflecting local plant diversity, life forms, and physiognomies. A positive relationship was observed between increased temperature and pollen production from trees and shrubs, and new pollen types were associated with indicator species of caatinga vegetation. Full article