In arid desert areas, Haloxylon ammodendron plays an important role in maintaining the ecological balance of desert oases. However, there are few studies on the physiological characteristics of Haloxylon ammodendron under an environmental gradient. Here, we studied the changes in the morphological and photosynthetic characteristics and their correlations in Haloxylon ammodendron in the four habitats of the Ebinur Lake wetland. Our results show that in high-water and high-salt habitats, photosynthesis is affected by “stomata restriction,” while in other habitats, photosynthesis is mainly affected by “non-stomata restriction.” In addition, when the soil conditions were good, Haloxylon ammodendron chose leaf construction featuring high specific leaf area, while when the soil conditions were worse, it chose an opposite leaf construction model to ensure the optimal allocation of carbon assimilation products in heterogeneous habitats. This study will deepen our understanding of the trade-off strategy between the accumulation and distribution of plant photosynthate in special habitats in arid areas. The results are of theoretical value for analysis of the ecological adaptation mechanisms of plants in arid desert areas.

Desert shrubs play an important role in the stability of arid and fragile desert ecosystems. However, despite their significant ecological importance, limited research has been performed on shrub drought tolerance strategies at the morphological, physiological, and molecular levels. Therefore, this study focused on the typical desert shrub, Calligonum leucocladum, and analyzed its morphology, physiology, and protein expression under two different habitats: moist low-salt and arid low-salt. The results indicate that drought stress inhibited the growth of C. leucocladum, leading to significant reductions in its plant height, base diameter, and crown width by 14.93%, 49.57%, and 48.49%, respectively. Drought stress triggered a 30% decline in stomatal conductance, whereas homeostasis was observed in net photosynthesis, intercellular CO₂, and transpiration. The soluble sugar content significantly increased by 13.43%, while the starch, soluble protein, and proline content significantly decreased by 20.32%, 10.67%, and 55.61%, respectively. In addition, under drought stress, membrane peroxidation products, reactive oxygen species metabolites, and antioxidant enzyme activities significantly increased. Weighted gene co-expression network analysis revealed 40 proteins that were significantly enriched in the photosynthesis and oxidative phosphorylation pathways through KEGG enrichment analysis. In addition, C. leucocladum maintains photosynthetic homeostasis by enhancing PSII repair (PsbE, PsbL, PsbH) and electron transfer chain efficiency (PetD, nad 2, nad 9), thereby compensating for the insufficient carbon dioxide supply caused by stomatal limitation. This study integrated multidimensional data from morphology, physiology, and proteomics to reveal that C. leucocladum drives a coupled network of photosynthesis, antioxidant, and carbon metabolism through chloroplast translation reprogramming. It maintains photosynthetic homeostasis and osmotic balance under a 30% decrease in stomatal conductance, elucidating the cross-scale regulatory strategy of desert shrubs adapting to extreme drought.

Growth is restricted by both water and phosphorus (P), and balancing the relationship between non−structural carbohydrates (NSCs) and carbon: nitrogen: phosphorus (C:N:P) is essential for Haloxylon ammodendron to adapt to arid habitats. The survival and growth strategies of the dominant species H. ammodendron in a desert ecosystem were examined in order to better serve the restoration of degraded ecosystems and desertification control. Three water and salt gradients (high water and high salinity, medium water and salinity, and low water and low salinity) in the Aibi Lake Reserve were selected. We analyzed the accumulation and distribution of NSCs in the assimilation branches and secondary branches of H. ammodendron and the changes in the measurement ratio characteristics of C:N:P, as well as the soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) content. The results showed that: (1) With the decrease of soil water and salt content, the basal diameter, plant height, crown area, and NSC content of H. ammodendron significantly decreased. This morphological adjustment in the aboveground part is similar to a “self thinning” behavior, aimed at reducing transpiration area and balancing carbon distribution in the body. The carbon accumulation in the body helps the H. ammodendron to resist the dual stresses of drought and salt. (2) With the decrease of water and salt content, the C content of assimilating branches increased significantly, while there was no significant change in secondary branches. However, the N and P content of both branches decreased significantly, and the N: P of both branches was greater than 16, indicating that it was mainly limited by P. (3) The NSC of the two branches was significantly negatively correlated with C, and significantly positively correlated with N and P, and there was a strong positive correlation between the assimilation branches NSC: C: P and NSC: C: P. The synthesis and accumulation of NSC of H. ammodendron were influenced by the content and relationship of C, N, and P, and the abundance of P content transported by the root system to the aboveground portion may have an important and decisive role in regulating nutrient balance and non-structural carbon dynamics.

Haloxylon ammodendron and Haloxylon persicum are ecologically and economically important drought-tolerant plants, often referred to as “desert guardians” owing to their remarkable abilities to withstand conditions of drought and salinity. We conducted a chromosome-level genome assembly using PacBio HiFi long-read sequences and Hi-C technology in order to gain a deeper understanding of their adaptive mechanisms and resource potential. The final assembled genome sizes were 2.32 Gb (contig N50 = 5.11 Mb; Scaffolds N50 = 257.59 Mb) for H. ammodendron and 1.32 Gb (contig N50 = 9.55 Mb; Scaffolds N50 = 143.67 Mb) for H. persicum, with 97.84% and 95.45% of the respective sequences anchored to nine pseudochromosomes. The BUSCO integrity scores were 88.40% and 84.00% for H. ammodendron and H. persicum, respectively. Gene annotation revealed that H. ammodendron contained 69,844 protein-coding genes, while H. persicum had 66,859 protein-coding genes, with repeat elements constituting 57.42% and 52.88% of their genomes, respectively. The reference genomes of Haloxylon serve as invaluable resources for exploring the ecological and economic significance of desert plants.

Global climate change-driven drought aggravation seriously threatens the survival and distribution of desert shrubs. Nitraria sibirica Pall. has outstanding drought tolerance, yet its growth adaptation strategies and internal regulatory mechanisms under different soil moisture conditions lack systematic research. This study combined physiological determination with transcriptome and metabolome analyses to investigate its physiological responses and molecular regulation mechanisms at different growth stages and habitats. Nitraria sibirica from riparian habitats exhibited lower leaf organic carbon and higher total nitrogen. Desert-grown N. sibirica possessed far more drought-responsive differentially expressed genes and metabolites than riparian ones. Hormone signal transduction and lipid metabolism dominated regulation in riparian habitats, whereas secondary metabolite biosynthesis and amino acid metabolism—especially flavonoid biosynthesis and tryptophan metabolism—were core in desert habitats. Its drought response displayed distinct stage-specificity, with hormone signal transduction most enriched in drought-responsive genes across growth periods. This study clarifies the stress adaptation mechanisms of desert shrubs and provides theoretical support for germplasm evaluation and vegetation restoration in arid regions.

Water limits plant growth and development in arid and semi-arid regions. The coordination among plant anatomy, stoichiometry, and non-structural carbohydra