Based on the fundamental principles of spatial heterogeneity and landscape ecology, landscape mosaic (LM) offers a more effective method for capturing variations in landscape spatial components, patterns, and ecological functions compared to land use and land cover (LULC). This advantage is particularly pronounced when employing the InVEST model to evaluate habitat quality (HQ), as field surveys often yield highly variable results that challenge the accuracy and applicability of LULC-based assessments. This paper focuses on the Taihang Mountain area in Hebei Province as the study region, utilizing the Principal Component Analysis (PCA), Self-Organizing Map (SOM), and Euclidean Distance (ED) model to achieve LM classification of the area. Based on this, the InVEST-HQ assessment is conducted, employing both OLS and GWR models to analyze the correlation between HQ and LM landscape patterns. The results indicate that (1) seven major LULC types were reclassified into nine pillar LM types and eleven transitional LM types, with a significant number of ecotone types emerging between different LULC types, among which cultivated land plays the most prominent role; (2) from 2000 to 2020, the overall HQ in the study area exhibited a continuous deterioration trend, particularly marked by a notable increase in functional areas of HQ areas classified as Level I; (3) factors such as the complexity of patch edges, the continuity between patches, and the diversity of patch types all significantly impact HQ. This study introduces an innovative methodological framework for HQ assessment using LM classifications within InVEST model, offering a robust foundation for comprehensive biodiversity monitoring and informed ecological management in the study area.

HKT proteins are the conserved voltage-gated ion channel proteins that act on the transmembrane transport of positive ions, but the evolutionary history of the HKT gene family is not clear. To create comparative HKT resources, we collected 134 HKT sequences in different phylogenetic lineages ranging from algae to angiosperms, encompassing fifty distinct taxonomic species. The evolutionary history of the HKT gene family was revisited through phylogenetic reconstruction. Phylogenetic reconstruction and comparative genomic analysis suggested that the HKT gene family originated from land plants and had a large number of tandem duplications. The evolution of HKT genes was mostly linear in non-seed plants. The genome duplication event was a potential factor in the change of the HKT gene copies in seed plants. In eudicots, the contraction event of HKT genes occurred every time the plant underwent a whole-genome duplication event after the ancient triplication. Amino acid sequence variations in the HKT transporters of TrkH domain influence their tertiary protein structure. Meanwhile, six HKT genes, represented by the Vitis vinifera, exhibit tissue-specific expression patterns and respond differentially to salt and drought stress. Frequent gene and genome duplications contributed significantly to the expansion/contraction of the HKT gene family. Our findings regarding the origin and evolution of HKT offer unique backgrounds and new insight into the functional evolution of this gene family.

Melatonin, a potent endogenous antioxidant, holds promise for enhancing stress tolerance in woody plants, yet its molecular mechanism under saline–alkali stress remains poorly understood. This study systematically investigated the effects of exogenous melatonin on Ulmus pumila ‘Zhonghua Jinye’ by integrating physiological assays, transcriptomics, and metabolomics. Two-year-old cuttings were subjected to 150 mmol·L⁻¹ saline–alkali stress and treated with varying melatonin concentrations (0, 50, 100, 200, 400 μmol·L⁻¹; three replicates). Physiological evaluations identified 100 μmol·L⁻¹ melatonin (SMT100) as optimal, significantly enhancing antioxidant enzyme activities (SOD, CAT, APX, GR) by 28.7–41.5% and reducing reactive oxygen species (H₂O₂ by 31.5%; O_2⁻ by 38.2%) compared to untreated stressed controls. Integrated omics analysis (CK, S, SMT100 groups) revealed that saline–alkali stress suppressed the flavonoid biosynthesis pathway, down-regulating key genes such as UpANS1 (10.74-fold), UpANS2, UpHCT1, and UpDFR2, thereby reducing the accumulation of protective flavonoids like quercetin and kaempferol. Conversely, melatonin treatment reactivated this pathway, significantly up-regulating UpANS1 (17.36-fold induction), UpDFR2 (5.55-fold), UpCHS1, UpF3H6, and UpLAR2. This genetic reconfiguration promoted the synthesis of antioxidant flavonoids, enhancing the plant’s overall stress resilience, thus identifying UpANS1 as candidates associated with treatment response. The study provides a scientific basis for cultivating U. pumila ‘Zhonghua Jinye’ in saline–alkali soils and clarifies the molecular mechanism by which melatonin alleviates combined saline–alkali stress via flavonoid pathway regulation.