Clonality is the ability of an organism, in natural conditions, to spontaneously produce independent or potentially independent offspring with the same genotype as their parents via clonal growth or clonal reproduction. Plants that possess clonality are clonal plants. They are ubiquitous in various types of ecosystems and dominate many ecosystems such as grasslands, tundra, wetlands and bamboo forests and play vital roles therein. Therefore, exploring clonal plants’ responses to and effects on changing environments and then their adaptive significances can deepen our understanding of the key processes and factors determining ecosystem composition, structure, functions and services, and help establish reliable natural solution-based ecosystem conservation and restoration techniques and programs. Starting from concept of plant clonality and clonal traits and in conjunction with over 40 years of progress in clonal plant ecology, we systematically tease out ecological responses of clonal plants to environmental changes, review the effects of clonal plants on ecosystems’ composition, structure, functions and services, and summarize basic and applied aspects of clonal plant ecology in the background of sustainable development. Finally, we propose future research directions of clonal plant ecology: using trait-based response-effect approach as new paradigm for clonal plant ecology/plant clone ecology; conducting clonal plant research in the context of vital eco-environmental challenges such as global climate change, land degradation, environmental pollution, biological invasion, and biodiversity loss; answering clonal plant ecology, plant clone ecology and and other-related scientific questions, at multiple organizational levels from individual to ecosystem; strengthening clonal plant research at the level of community/ecosystem; exploring phylogenetic pattern and molecular evolution process of plant clonality.

Changes in subsurface ecological processes in the context of global change have become one of the hot issues of concern in the field of ecology. Mycorrhiza are symbiotic relationships between plant roots and mycorrhizal fungi, widely distributed in terrestrial ecosystems. As two major types of mycorrhizal fungi related to trees, arbuscular mycorrhizal fungi and ectomycorrhizal fungi exhibit significant differences in morphology and function. Root exudates, as an important medium for exchange of matter, energy, and information between plants and soil, play a crucial role in soil carbon dynamics. The root exudates of tree species associated with different mycorrhizal types can actively respond to environmental changes by continuously adjusting their quantity and chemical composition, and influence the belowground carbon dynamics and cycling processes of forest ecosystems. Currently, the composition and function of root exudates from different types of mycorrhizal fungi, as well as the variation and impact on plant and soil, remain unclear. Therefore, the article combines current frontier dynamics in the field both domestically and internationally, and summarizes the root exudate characteristics, influencing mechanisms, and rhizosphere effects of tree species associated with different mycorrhizal types. This review is expected to provide references for further research on the response and adaptation mechanism of root systems and exudates to global changes. In addition, it also proposes directions for future research on root exudates among different types of mycorrhizal fungi that require further investigation: (1) strengthening systematic research on root exudates among different types of mycorrhizal fungi; (2) studying the influence mechanism of mycorrhizal type on root exudates in combination with other environmental factors; (3) using more precise technological means to comprehensively understand the changes in root exudate characteristics among different types of mycorrhizal fungi; (4) deeply revealing the influencing mechanism of root exudates among different types of mycorrhizal fungi from the perspective of plant physiology and metabolism; (5) conducting long-term dynamic monitoring and simulation experiments on different types of mycorrhizal fungi to predict their impact on soil ecological processes.

In the context of carbon sequestration and emission reduction and the "Dual Carbon" goals, currently, the impact of climate change, characterized by the combined changes of elevated atmospheric carbon dioxide (CO2) concentration and warming, on the dynamic changes of soil organic carbon (SOC) has become a research hotspot. The interaction and coupling mechanism between climate change and SOC pools have always been a difficult issue in academic research. Most previous studies have examined the driving processes and mechanisms of climate change on SOC pool changes from the perspectives of plant growth, litter substrate quality, soil physicochemical properties, organic carbon physical/chemical components, and microbial community structure. Moreover, research on the impact of climate change on terrestrial ecosystem carbon processes is still based on a single factor of elevated CO2 concentration or warming. Based on the research progress at home and abroad, this review summarizes the effect and mechanism of elevated CO2 concentration and warming on soil organic carbon accumulation. We combine the coupling effects of soil organic carbon fractions, molecular composition, structural characteristic, differences in response between topsoil and subsoil, and organic carbon stability, so as to reveal the intrinsic mechanism of elevated CO2 concentration and warming on organic carbon accumulation and transformation. On this basis, future research should focus on (1) clarifying the coupling relationship between SOC end inputs, molecular composition, as well as structural characteristic, and (2) revealing the impact mechanism of long-term climate change on the stability and burial potential of SOC in multiple ecosystems. To clarify soil carbon source/sink functions, it is necessary to comprehensively and deeply understand the biogeochemical processes of SOC sources, transformation, burial, and decomposition in terrestrial ecosystems under climate change, aiming to provide scientific theoretical basis for soil carbon neutrality management decisions in the future.

Aims Mongolian Plateau grasslands are the core of the Eurasian grassland ecosystem and an important ecological barrier in northern China. Climate change has led to a significant increase in the intensity, frequency, and duration of drought events on the Mongolian Plateau. Therefore, quantitatively assessing the resistance and resilience of the Mongolian Plateau grasslands helps to deepen our understanding of grassland responses to climatic anomalies. However, few studies have explored the resilience and resistance of different grassland types on the Mongolian Plateau to consecutive droughts. Methods In this study, based on long-term series data of the Standardized Precipitation Evapotranspiration Index (SPEI) and Net Primary Productivity (NPP) from 2000 to 2020, we quantified the resistance and resilience of the Mongolian Plateau grassland ecosystem to consecutive droughts (1–4 years) and its spatiotemporal variations. Furthermore, we compared the differences in the responses of three main types of grasslands (meadow steppe, typical grassland, and desert steppe) to extreme and moderate droughts. Important findings Our results show that: (1) except for two consecutive years of drought, the resistance of grasslands under moderate drought is generally higher than that under extreme drought, but the opposite is true for resilience. (2) As the number of consecutive drought years increases, the resistance of grasslands under both extreme and moderate droughts shows a declining trend, but resilience shows an increasing trend under extreme drought and a decreasing trend under moderate drought. (3) Among the three different grassland types, meadow steppe has the highest resistance, followed by typical steppe and desert steppe. Conversely, desert steppe has the highest resilience, followed by meadow steppe. (4) Over time, the resistance of grasslands was higher in 2011–2020 than in 2001–2010, but with the opposite trend for resilience. With the increase in consecutive drought years, the resistance of the three types of grasslands shows a declining trend in both 2000–2010 and 2011–2020, but the resilience shows an increasing trend first (2000–2010) and then a decreasing trend (2011–2020). This study is of great significance for maintaining the important ecological barrier of the Mongolian Plateau, ensuring its ecological service functions, and promoting regional and global ecological security and sustainable development.

Aims The accumulation of nutritional components in plants is critically linked to their survival capacity and productivity. Investigating how arbuscular mycorrhizal fungi (AMF) inoculation regulates drought tolerance in plants through nutrient component changes in various organ will establish a theoretical framework for applying AMF to improve crop resilience under water-limited conditions. Methods A controlled pot experiment employing two water regimes (75% vs.55% field capacity) with AMF inoculation was conducted using oat (Avena sativa) cultivar Bayou 1. Mycorrhizal colonization rates were quantified at jointing and filling stages, followed by analysis of non-structural carbohydrates (NSC), C, N, P in root, stem, and leaf. Grain yield was recorded at the maturity stage. Important findings In oat plants inoculated with AMF under drought stress, the AMF colonization rate, plant height, and root-to-shoot ratio were significantly enhanced, resulting in 13.31% increase in grain yield. Notably, these improvements in growth parameters and yield exceeded those observed in AMF-inoculated plants under well-watered conditions. Furthermore, AMF inoculation under drought stress increased soluble sugar accumulation in stem and leaf. Concurrently, the contents of C, N, P in root, stem, leaf, as well as the leaf C:N significantly increased, especially the contents of P in leaf. In contrast, the leaf N:P significantly declined. Redundancy analysis revealed that the contents of leaf soluble sugars, and stem C, root N content served as key indicators explaining variations in growth traits and grain yield under drought stress and AMF inoculation, respectively. Overall, AMF inoculation under drought conditions enhanced oat drought tolerance and hence improved grain yield, primarily attributed to increase AMF colonization rate, which facilitated synergistically the accumulation of soluble sugar and C, N, P in organs, and modulated the leaf stoichiometric ratios (C:N and N:P).

Aims With the development of precision agriculture, real-time monitoring and accurate prediction of crop growth status and yield have become crucial. However, traditional monitoring methods are often limited by factors such as time, manpower, and cost, making it difficult to meet the needs of modern agricultural management. The aim of this study was to use PhenoCam to monitor the growth of artificial forage and extract phenological metrics to estimate the yield. Methods GCC, NDVI and LCI were extracted from phenological photos and UAV images of silage maize and oat under different fertility treatments. The phenological metrics were calculated by fitting and combining the vegetation growth curves of GCC. The relationship between phenological metrics and plant height and yield of two kinds of artificial forage was studied by linear fitting, and the best fitting model of phenological metrics to harvest characteristic was constructed. Important findings (1) Nitrogen application rate drove the phenological metrics and harvest characteristic of artificial forage. The growing period length of maize silage under high fertilizer treatment and oat under medium fertilizer treatment was the longest (68?5 days and 59?1 days), and the corresponding yield was the highest (1903.22?284.62 kg/ mu and 345.38?129.27 kg/ mu, respectively). (2) GCC and LCI had the best correlation with the plant height of artificial forage, especially before GCC reached the peak POP (pre-POP R2 was 0.86 and 0.49), and GCC had the smallest deviation in dynamic capture of plant height of silage maize. (3) The phenological metrics of artificial herbage can effectively predict the measured maximum plant height and final yield (R2 of silage maize were 0.328 and 0.829, and R2 of oat were 0.995 and 0.935). This study confirmed the effectiveness of phenological metrics based on Phenocam and UAV images in monitoring the growth status and yield of artificial forage grass.

Aims Intra-annual radial growth monitoring using the micro-coring method provides high-resolution and dynamic tree growth information, which is essential for understanding the trees’ responses to climate change. Methods In this study, we utilized the micro-coring method to monitor the seasonal growth dynamics of Pinus koraiensis and Ulmus japonica in the mixed broadleaf-Korean pine forest of Changbai Mountain. Important findings Our comparative analysis revealed the following: (1) The cell enlargement onset for U. japonica (day of the year (DOY) 116.0 ± 4.7) occurred earlier than for P. koraiensis (DOY 125 ± 2.64), with both species showing a similar trend of initial increase followed by a decrease in cell enlargement length. (2) The onset of the growth rate peak for P. koraiensis occurred earlier than for U. japonica, but the growth duration of U. japonica was longer than that of P. koraiensis. The average xylem growth rate of P. koraiensis was 3.4 μm·d–1, with a maximum rate of 9.4 μm·d–1, whereas for U. japonica, the respective rates were 11 and 23 μm·d–1. (3) Both species exhibited highly consistent response trends to environmental factors, although the response intensity of U. japonica to climatic factors was lower than that of P. koraiensis. The radial growth lengths of both species showed significant positive correlations with mean temperature, maximum temperature, minimum temperature, relative humidity, and soil temperature, and significant negative correlations with photosynthetically active radiation and vapor pressure deficit. No significant correlations were observed with soil moisture content and precipitation. The temperature is consistently the primary climatic factor influencing the radial growth of P. koraiensis and U. japonica during the year, with soil temperature being the most critical climatic factor.

Aims This study aimed to investigate intraspecific variation in seed morphology and germination traits of Primula denticulata across elevational gradients in a mountain ecosystem, providing insights into ecological adaptations of plants to environmental changes. Methods Seeds from 13 P.denticulata populations were collected along an elevational gradient of 2180–3451 m in the Gaoligong Mountains of southwestern Yunnan in China. Seed traits, including length, width, width-to-length ratio, perimeter, area, optimum germination temperature (To), germination percentage (GP), mean germination time (MGT), variance in germination rate (VGR) and germination synchronization (GS) at the optimum temperature of seeds, were assessed. Relationships between seed morphology and elevation, as well as between germination traits and elevation, were also determined. Important findings Results showed that: (1) Seed width, area and 100-seed mass of P.denticulata increased significantly with increasing elevation, while seed length, width-to-length ratio and perimeter showed no significant change. (2) To decreased significantly with increasing elevation. At To, the MGT increased significantly and GS decreased significantly with increasing elevation. However, GP and VGR were not markedly impacted by elevation. (3) Elevation had a significant positive effect on seed width, area, and 100-seed mass, with these morphological variations contributing to longer MGT and reduced GS along the elevational gradient. These findings indicate that the width and mass of P.denticulata seeds increased with elevation, leading to delayed germination and lower synchronization. This suggests that high-elevation populations tend to adopt a “long bet”germination strategy.

Aims In-depth research on the hydraulic traits of plant xylem and leaf functional traits would be helpful to reveal their adaptation strategies to the environment, providing a theoretical basis for vegetation management and restoration. Methods This study focuses on three typical shrub species in the mixed Pine-Quercus forests of Beijing mountains areas: Vitex negundo, Grewia biloba, and Morus mongolica. Leaf functional traits (e.g., leaf area, net photosynthetic rate, leaf water potential, etc.) are determined through outdoor measurements and indoor experiments, while the xylem anatomical structure of the roots, stems, and branches of the three shrub species (e.g., vessel diameter, vessel density, etc.) is observed through sectioning, and hydraulic traits (e.g., specific hydraulic conductivity, hydraulic vulnerability index) are calculated, so as to understand the plant hydraulic structure and leaf functions and to reveal the adaptation strategies of these three shrub species to the shaded understory environment. Important findings (1) Significant differences in leaf morphology, hydraulics, and functional traits are observed among the three shrubs; Vitex negundo has smaller leaf area but greater specific leaf mass, with the highest specific leaf mass and net photosynthetic rate; Grewia biloba has the largest vein volume but the lowest net photosynthesis and transpiration rates; Morus mongolica has the largest leaf area and midday leaf water potential. (2) Notable differences are found in the xylem vessel characteristics and hydraulic traits of the roots, stems, and branches of the three shrubs; Vitex negundo’s aboveground water transport efficiency exceeds that of its underground part; Grewia biloba maintains a balanced water transport efficiency across all xylem parts, with the strongest resistance to embolism; Morus mongolica maintains high water transport efficiency in all parts, with the weakest resistance to embolism. (3) Correlation analysis indicates that the xylem hydraulic traits of the three shrubs influence most of the variations in leaf structural traits and hydraulic traits. (4) Principal component analysis reveals that Grewia biloba tends towards a conservative slow strategy, Morus mongolica leans towards a water-consuming fast strategy, and Vitex negundo’s adaptation strategy lies between the former two.

This study investigated the physiological and biochemical characteristics and adaptability of Rhododendron tomentosum in four forest types (Betula platyphylla forest, Larix gmelinii forest, the mixed coniferous broad leaved forest where the dominant species in the tree layer is B. platyphylla and L. gmelinii, and Pinus pumila forest), and conducted a fuzzy evaluation of each forest type to comprehensively investigate the physiological and ecological characteristics and adaptability of Rhododendron tomentosum under different forest types. The results showed that different forest types had significant effects on the photosynthetic physiological characteristics of R. tomentosum. In B. platyphylla forest, R. tomentosum showed strong photosynthetic ability, high photosynthetic pigment content, high antioxidant enzyme activity, relatively high total polyphenols and total flavonoids content, and strong photosynthetic growth and stress resistance, which indicated that R. tomentosum was better adapted to this forest type. In mixed coniferous broad forest and L. gmelini forest, R. tomentosum had high volatile oil content, and the rest of the indexes were in the moderate level, and the adaptability was moderate. However, in P. pumila forest, the photosynthetic capacity of R. tomentosum was weak, the antioxidant enzyme activity was low, and the stress tolerance was relatively weak, but its total polyphenols and total flavonoids and anthocyanins content was high to adapt to the high alpine environment, which showed a certain degree of adaptability to the environment. This study provides a theoretical basis for the in-depth understanding of the growth pattern and adaptive mechanism of R. tomentosum under different forest types, and also provides theoretical support and practical guidance for the ecological protection, resource utilization and forestry production of R. tomentosum.

Aims Loquat (Eriobotrya japonica) is evergreen tree that often suffers photoinhibition or photodamage at low temperature in winter, which affects its growth. Therefore, this study explored the photoinhibition of two photosystems of loquat leaves in winter. Methods In this study, the photoinhibition of two photosystems of loquat leaves in winter was compared using simultaneous measurements of chlorophyll fluorescence and 820 nm light reflection. Important findings From autumn to winter, the maximum quantum yield of photosystem II (PSII) (Fv/Fm) in loquat leaves decreased significantly, while the photosynthetic electron transfer capacity at both the donor and acceptor sides of PSII did not change. The activity of photosystem I (PSI) did not change either. However, the actual photochemical efficiencies of both PSII and PSI decreased significantly. Non-photochemical quenching decreased significantly under high light. From winter to spring, the value of Fv/Fm in loquat leaves increased significantly. The electron transfer capacity at the acceptor side of PSII and the activity of PSI also decreased. Moreover, the actual photochemical efficiency of PSII increased significantly, while that of PSI remained unchanged. Non-photochemical quenching increased significantly under high light. These results indicate that the photoinhibition of PSI occurred later than PSII in loquat leaves in winter. The activity of PSI also recovered slowly. Photoinhibition of PSII occurred earlier, and its activity recovered earlier.

Aims Long-term grazing profoundly affects the external environment for plant growth and development in grassland ecosystems, and plants adapt to environmental changes through interactions with rhizosphere microbes. However, there is limited research on how grazing affects the rhizosphere microbial diversity of plants with different survival strategies in grasslands. Methods In this study, based on the long-term grazing experimental platform of typical grasslands in Inner Mongolia, we selected the dominant plant species Stipa grandis and Cleistogenes squarrosa as research subjects. Using high-throughput sequencing technology, we explored the trends in rhizosphere bacterial diversity under different grazing intensities (control, light: 1.5 sheep·hm–2, moderate: 4.5 sheep·hm–2, and heavy: 7.5 sheep·hm–2), and analyzed the differences in the responses of two dominant plant rhizospheric bacteria and their intrinsic connection with plant functional traits. Important findings The results showed that: (1) Heavy grazing significantly reduced the rhizosphere bacterial richness (8.97%) and Chao1 index (9.48%) in Stipa grandis, but had no significant effect on the rhizosphere bacterial α-diversity of Cleistogenes squarrosa. Additionally, the α-diversity of Stipa grandis was significantly lower than that of Cleistogenes squarrosa. Moreover, heavy grazing significantly altered the bacterial community composition of both plant species, with the change being more pronounced in Stipa grandis than in Cleistogenes squarrosa. (2) As grazing intensity increased, Stipa grandis was enriched with both plant growth promoting rhizobacteria and biocontrol agents, Cleistogenes squarrosa whereas was primarily enriched with plant growth promoting rhizobacteria. (3) Changes in the diversity and relative abundance of rhizosphere bacterial communities in Stipa grandis were significantly correlated with its larger root diameter, lower specific leaf area, and lower specific root length, which reflect grazing avoidance and resource-conserving strategies. In contrast, changes in the bacterial communities of Cleistogenes squarrosa were significantly correlated with its higher C/N ratio in aboveground biomass and larger specific leaf area, which reflect grazing tolerance and resource-consuming strategies. In conclusion, this study demonstrated that the responses of rhizosphere bacterial communities in different dominant plant species to grazing pressure are closely related to their survival strategies, enriching our understanding of the synergistic adaptations between plants and rhizosphere microbial communities in the context of long-term grazing.