Wetlands are crucial ecosystems that provide a wide range of ecological services, such as water purification, flood control, and carbon sequestration, where the diversity of wetland plants is fundamental to maintaining these functions. Phragmites australis is a globally widespread wetland grass with a high genetic diversity, exhibiting strong intraspecific variation across environmental gradients. While both phenotypic plasticity and genetic variation are recognized drivers of plant adaptation, their relative importance in mediating the growth and decomposition traits of wetland plants remains debated. Here, we surveyed the growth and litter traits of two lineages (haplotypes) of P. australis in two common gardens in eastern China. The leaf litter of P. australis was also collected from the field in two provinces where the two common gardens are located. Microcosm experiments were carried out to explore the litter decomposition ability. We found that the common garden (growth environment) significantly affected the growth performance (shoot diameter and height), leaf litter stoichiometric traits (contents of N and P), and the leaf decomposition over 180 days. The N content in the leaf litter from the higher-latitude province of Liaoning was greater than that from the lower-latitude province of Shandong, regardless of whether it was collected from the field or the common garden. The litter N and P contents were the key factors affecting the decomposition during the 180-day experiment. However, we did not find the effects of lineage (genetic variation) on the variation of these traits. The climatic factors of the genotype origin were significantly correlated with the growth traits but not the litter traits or decomposition rates. The findings indicate that P. australis in eastern temperate China primarily adapts through phenotypic plasticity rather than genetic variation, which is crucial for wetland resilience in a changing climate. This study underscores the pivotal role of environmental factors and phenotypic plasticity in P. australis growth and decomposition, suggesting that conservation efforts should prioritize the local environment over genetic variation for effective wetland management.

Salinization and eutrophication are increasingly severe pollution problems in wetlands. Myriophyllum spicatum is a cosmopolitan species widely used for pollution control, but its physiological responses under combined stressors remain largely unknown. Here, we used mesocosms to investigate the ecophysiological responses of M. spicatum to three ammonia nitrogen concentrations (0, 1.5, and 3 mg L⁻¹) and two salt concentrations (0 and 5 g L⁻¹). Shoot and stem biomass were significantly affected by both salinity and nitrogen, whereas leaf phosphorus and stem nitrogen responded only to salinity (two-way ANOVA, p < 0.05). A significant salinity–nitrogen interaction was observed for stem biomass (p < 0.05); specifically, low nitrogen alone caused no significant reduction, but under saline conditions it markedly exacerbated biomass suppression. A significant salt–nitrogen interaction was detected for stem biomass (p < 0.05), such that low nitrogen alone did not significantly reduce stem biomass but exacerbated its suppression under saline conditions. These indicate potential synergistic environmental effects and suggest that even low nutrient inputs may aggravate stress under salt exposure. Stem biomass was significantly negatively correlated with malondialdehyde content (Pearson analysis, p < 0.05). Salt–nitrogen co-stress significantly increased malondialdehyde content (Tukey HSD test), indicating enhanced lipid peroxidation and associated oxidative damage, which may represent a physiological mechanism underlying growth inhibition in M. spicatum. Our findings demonstrate the complex adaptive responses of M. spicatum and emphasize the need to consider salt–nutrient interactions in conservation and restoration practices.

Understanding morphological descriptions of plants documented by ancient peoples over 1000 years ago and identifying the species they described are critical for reconstructing the natural geographic distribution of plant taxa, tracking taxonomic variations, and inferring historical climate dynamics. Analyzing shifts in plant communities and climatic conditions during this period is essential to unravel the interplay among floristic composition, climate fluctuations, and anthropogenic impacts. However, research in this field remains limited, with greater emphasis placed on plant taxa from hundreds of millions of years ago. Investigations into flora and climate during the last two millennia are sparse, and pre-millennial climatic conditions remain poorly characterized. In this study, a historical text written 1475 years ago was analyzed to compile plant names and morphological features, followed by taxonomic identification. The research identified three gymnosperm species (one in Pinaceae, two in Cupressaceae), 1 Tamaricaceae species (dicotyledon), and 19 dicotyledon species. However, three plant groups could only be identified at the genus level. Using textual analysis and woody plant coexistence methods, the climate of 1475 years ago in western Henan Province, located in the middle-lower Yellow River basin in East Asia, was reconstructed. Results indicate that the mean temperature of the coldest month (MTCM) was approximately 1.3 °C higher than modern values. In comparison, the mean temperature of the warmest month (MTWM) and mean annual temperature (MAT) were lower than present-day levels. This suggests slightly cooler overall conditions with milder seasonal extremes in ancient Luoyang—a finding supported by contemporaneous studies. Furthermore, annual precipitation (AP), precipitation of the warmest quarter (PWQ), and precipitation of the coldest quarter (PCQ) in the Luoyang region 1475 years ago exceeded modern measurements, despite the area’s monsoonal climate. This suggests significantly higher atmospheric moisture content in ancient air masses compared to today. This study provides floristic and climatic baseline data for advancing our understanding of global climate variability at millennial scales.

Accurately understanding the morphological descriptions of plants by ancient people more than 1,000 years ago, and determining the plant species that people described, is of great value in understanding the natural geographic distribution of plant taxa, the var-iation of plant taxa, and climate change. The variation on the plant group and the climate at that time is critical for understanding the change of combination of plant taxa and the climate and the impact of human activity. However, there is limited research in this area. More studies have focused on plant taxa from billions of years ago or money millions of years ago. Research on the plants and flora of this period is limited. And little was known about climates prior to the millennium. In this study, the special text was selected, and the plant names, plants' morphological features were gathered and plant taxonomy were carried out. The study identified 3 species of gymnosperms, namely Pinaceae and Cu-pressaceae, one species of Tamaricaceae monocotyledon, and 19 species of dicotyledons. However, three plant groups could only be identified to the level of genus. In our study, we reconstruct the climate of 1.475 millennia ago through plant textual research and woody plant coexistence analysis in the western section of Henan Province in eastern Asia, in the middle and lower reaches of the Yellow River. The results showed that the mean temperature of the coldest month was around 1.3°C higher than that in modern times, the mean temperature of the warmest month and mean annual temperatures were lower than the corresponding modern values 1.475 millennia ago, implying that tem-peratures in the Luoyang region were slightly lower with a respective mild change at the time, which was supported by other studies of the same period. At the same time, the study concluded that 1.475 millennia ago, the ancient Luoyang region, located in the interior of central East Asia, had high temperatures and rainfall in the summer and low temperatures in the winter, but the mean annual precipitation, the hottest seasonal pre-cipitation, and the coldest seasonal precipitation were all higher than those in the modern Luoyang region. Despite East Asia's predominantly monsoonal climate, the water con-tent of air currents was significantly higher than it is today. This study provides high-resolution plant and climate background information for rebuilding the ecological environment in East Asia.