R. platypodum (Rhododendron platypodum) is an endangered alpine species with a highly restricted distribution in the southwestern region of China, which possesses significant ornamental and horticultural value. In this study, the high-quality genome assembly of R. platypodum at the chromosomal level is reported. The total genome size was determined to be 642.25 Mb, with a contig N50 of 25.64 Mb, and it contains 36,522 predicted genes. Comparative genomic analysis between R. platypodum and other species revealed the expansion of gene families, such as those related to transition metal ion binding and sodium ion transport, as well as the contraction of gene families involved in the recognition of pollen and pollen–pistil interaction. These findings might explain the adaptation of R. platypodum to rocky habitats and contribute to its endangered status. Furthermore, a heat stress experiment was conducted on R. platypodum, followed by transcriptome sequencing and physiological co-analysis to construct a co-expression network. This analysis identified the candidate gene TAR1-A and other transcription factors exhibiting differential expression under heat stress. The whole-genome sequencing, transcriptome analysis, and physiological co-analysis of R. platypodum provide valuable resources for its conservation and offer insights into its mechanisms of heat stress.

Water environment quality is profoundly driven by a series of landscape characteristics. However, current knowledge is limited to the independent response of water quality to single landscape elements; this has led to poor knowledge of the potential role of structural coupling within landscapes in driving water quality changes, especially in those agroforestry-mixed mountainous watersheds with highly embedded forest-clustered landscapes and abundant headstreams. Given this fact, this study aims to evaluate whether and how the source–sink coupling structure of forest-clustered landscapes systematically drives headstream quality dynamics. We first systematically assessed the association pattern of source and sink structures within forest-clustered landscapes, and then innovatively proposed and constructed a functional framework of source–sink coupling structure of landscapes across 112 agroforestry-mixed mountainous sub-watersheds in Chongqing, China. On this basis, we further evaluated the driving pattern and predictive performance of the source–sink coupling structure of landscapes behind headstream quality dynamics. We report three findings: (1) headstream quality varied across agroforestry-mixed sub-watersheds, mapping out the source–sink structures and functions of landscapes; (2) there was significant functional coordination between source–sink structures of the forest-clustered landscapes, which significantly drove headstream quality dynamics; (3) the structural positioning and differences of the forest-clustered landscapes along the multivariate functional axes directly corresponded to and predicted headstream quality status. These findings together highlight a key logic that the response of water quality dynamics to landscapes is essentially that to the functional coupling between the source–sink structures of landscapes, rather than the simple combination of a single landscape contribution. This is the first study on the landscape–runoff association from the perspective of source–sink structural coupling, which helps to deepen understanding of the correlation mechanism between water dynamics and landscape systems, and provides a new functional dimension to the development of future landscape ecological management strategies from a local to a global scale.

Unstable roadside slopes in mountainous forested regions pose significant challenges for ecological restoration and the maintenance of forest ecosystem integrity. While passive (spontaneous) vegetation recovery offers a low‐cost and sustainable strategy, the underlying ecological drivers—particularly the role of adjacent forests and propagule sources—remain poorly understood. In this study, we examined 14 naturally restored roadside slopes and their adjacent forests in the subtropical mountains of southwestern China. Across 126 slope plots and 252 forest plots, we recorded 249 vascular plant species and assessed species composition, dispersal traits, and phylogenetic similarity between habitats. We found that 95.9% of slope species were native, with 80.0% exhibiting long‐distance dispersal traits, mainly through wind and birds. Approximately 65.3% of slope species were shared with adjacent forests, and the average phylogenetic similarity was relatively high (0.589), indicating that nearby forests act as key propagule sources. Structural equation modeling showed that species overlap and phylogenetic similarity were significantly influenced by forest species richness, forest cover, distance to core protected areas, and plant dispersal strategies. Phylogenetic dissimilarity between slope and forest communities was largely driven by lineage turnover, with nestedness contributing particularly in slope–forest pairs with close spatial proximity. These findings underscore the ecological importance of conserving adjacent forest habitats to facilitate spontaneous vegetation recovery on disturbed slopes. They also demonstrate that forest proximity, propagule pressure, and dispersal efficiency are critical to the success of passive restoration. From a management perspective, strategies should focus on maintaining forest connectivity and promoting landscape‐scale seed flow to enhance biodiversity recovery and slope stability in mountainous forest ecosystems.