Climate warming is reshaping alpine and tundra vegetation, but its effects on shrub radial growth and vessel anatomy remain unclear. We used a five-year open-top chamber experiment on Changbai Mountain to examine radial growth and vessel traits in the evergreen Rhododendron aureum and the deciduous Vaccinium uliginosum. Warming increased ring width (RW), vessel number (VN), and total vessel area (TVA) in R. aureum, whereas no significant changes occurred in V. uliginosum. However, the interactions of species and treatment were not significant. Mean vessel area (MVA), vessel density (VD), hydraulic diameter (Dh), and theoretical hydraulic conductivity (Kh) did not respond significantly to warming in either species. Repeated measures correlations showed that RW was positively correlated with MVA and Dh only under ambient conditions in R. aureum, but under both treatments in V. uliginosum. Under ambient conditions, RW and vessel traits were correlated mainly with temperature in R. aureum and soil moisture in V. uliginosum. Fewer significant correlations with environmental variables were detected under warming. Mixed effects models showed positive associations of RW with MVA and Dh in R. aureum and a negative association with VD in V. uliginosum. Overall, warming increased radial xylem production in R. aureum without marked changes in vessel dimensions and density, whereas V. uliginosum maintained relatively stable radial growth and vessel anatomy. Our study provides experimental evidence that stem xylem anatomical traits can help explain shrub responses to warming in alpine tundra ecosystems.
Saline–alkaline soils constrain grassland productivity and forage utilization, but intraspecific variation in plant responses to these conditions remains insufficiently understood. Here, two Leymus chinensis cultivars with contrasting leaf-color phenotypes, the gray-green cultivar Xilamuren (GG) and the yellow-green cultivar Huanggangliang (YG), were compared under the same saline–alkaline field conditions. The field experiment comprised three independent plots per cultivar. Phenological progression, morphological traits across six developmental stages, lignin characteristics, physiological and biochemical traits, and integrated transcriptomic and metabolomic profiles were evaluated during the 2024 growing season. YG initiated regreening approximately 26 d earlier than GG and exhibited a distinct seasonal growth trajectory. At heading, lignin content was 30.9% higher in YG than in GG; by full maturity, the relative difference between the cultivars had narrowed to 14.0%. At heading, GG exhibited higher photosynthetic performance and a more favorable shoot nutrient status, whereas at full maturity, YG maintained higher antioxidant enzyme activities and lower lipid peroxidation. Transcriptomic analysis identified 5551 upregulated and 954 downregulated genes in YG relative to GG. Integrated transcriptomic and metabolomic analyses further revealed marked differences in phenylpropanoid and flavonoid metabolism, accompanied by contrasting expression patterns of lignin- and flavonoid-related genes. These results demonstrate that the two cultivars differ in the temporal coordination of growth-related traits, lignification, physiological regulation, and secondary metabolism under saline–alkaline field conditions.
Plants’ capacity to detect and react to changes in water availability and temperature is essential for their physiological tolerance and is a crucial ecological trait with significant evolutionary consequences. Understanding the capacity of threatened species to rapidly acclimate and adjust their metabolism is critical for guiding restoration and conservation strategies. This study evaluated Dyckia rariflora's responses to combined water deficit and high-temperature stress under controlled conditions. Dyckia rariflora is a threatened and endemic species from the ferruginous outcrops (canga ecosystems) of the Iron Quadrangle in Brazil. Four treatments were applied: (i) well-watered (WW); (ii) WW + high temperature (32/27 °C day/night); (iii) water deficit (WD) under ambient temperature; and (iv) WD + high temperature. Morphological adjustments, including leaf rolling and hypodermis reinforcement, occurred alongside reduced water status, especially in WD and WD + HT. The arrangement of peltate scales in rows along the intercostal grooves of the abaxial epidermis protects stomata from excessive radiation and heat, and may also slow water loss in vapor form. Enhanced photoprotection (carotenoid accumulation), activation of antioxidant pathways, and increased synthesis of sugars, amino acids, and polyols constituted the main lines of defense against the combined stress. Upregulation of the shikimate and phenylpropanoid pathways, leading to elevated levels of phenolic acids, flavonoids, and phytosterols, indicated a major metabolic reconfiguration that maintained cellular integrity. These findings can guide management strategies for the species reintroduction in canga environments, helping to determine the best planting times and enhance long-term survival.
Drought is one of the major constraints limiting wheat productivity, yet the molecular mechanisms underlying contrasting drought-response strategies remain incompletely understood. Here, we combined physiological phenotyping with quantitative subcellular proteomics to investigate drought responses in two winter wheat cultivars exhibiting contrasting water-use strategies: the water-saving cultivar Baletka and the water-spending cultivar Tobak. Nuclear- and chloroplast-enriched protein fractions were analysed by LC-MS/MS during short-term drought, prolonged drought, and recovery, and integrated with biomass and physiological measurements. Both cultivars exhibited extensive drought-induced proteome remodelling; however, their responses differed markedly in organization and physiological coordination. Water-saving Baletka showed stronger integration between proteomic and physiological responses, with enhanced regulation of proteins involved in stress signalling, redox homeostasis, protein protection, and transcriptional control, supporting maintenance of leaf water status and photosynthetic performance. In contrast, water-spending Tobak displayed broader remodelling of chloroplast proteins associated with photosynthesis, carbon metabolism, and protein turnover, reflecting a greater requirement for repair under prolonged water deficit. Integration of protein abundance with physiological traits identified cultivar-specific regulatory networks linking nuclear and chloroplast functions with drought adaptation. Germin-like proteins emerged as key candidates associated with oxalate metabolism and intercellular CO₂ concentration, supporting a potential role for oxalate-derived CO₂ recycling during drought. Together, these findings demonstrate that subcellular proteomics provides mechanistic insight into genotype-dependent drought acclimation by revealing compartment-specific regulatory processes that are not apparent from whole-leaf analyses. The identified proteins and pathways represent promising targets for improving drought resilience in wheat.
