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Microbial leftovers, known as necromass, are key players in storing carbon in the soil around plant roots (i.e. rhizosphere), a zone characterized by high‐efficiency microbial anabolism. Yet, the extent and mechanisms through which the rhizosphere contributes to soil organic carbon (SOC) via microbial necromass, especially under changing environments remain unclear. We aimed to evaluate the contributions of microbial necromass to SOC and influencing factors from the rhizosphere perspective. We collected the rhizosphere and bulk soil from 39 alpine coniferous forest sites on the eastern Tibetan Plateau to assess the extent of microbial necromass contribution to SOC in the rhizosphere from a dynamic perspective by calculating the ratio of increased amino sugars (AS) to increased SOC in the rhizosphere relative to that in bulk soil (RAS/SOC). We also collected climate data and determined nutrient concentrations and microbial physiological traits in rhizosphere soil to elucidate the factors affecting RAS/SOC. The results showed that across all sampling sites, the average concentrations of SOC‐normalized AS in the rhizosphere were significantly higher than those in the bulk soil. Furthermore, the average RAS/SOC was greater than 1, indicating a faster microbial necromass accumulation than SOC accumulation in the rhizosphere. These results implied that the rhizosphere sustains a greater capacity for microbial necromass contribution to the SOC pool than the bulk soil does. Soil nutrient availability was the primary factor affecting RAS/SOC, and precipitation indirectly affected microbial anabolism and RAS/SOC by changing soil nutrient status. Additionally, with increasing rhizosphere soil nutrient availability, microbial carbon‐use efficiency and growth rate increased but the biomass‐specific enzyme activity declined, indicating that microorganisms tended to exhibit high‐yield strategies with increasing soil nutrient availability. Synthesis. Our findings underpin the vital effect of microbial necromass in SOC accumulation from the rhizosphere perspective and offer valuable insights into mechanisms underlying microbial C metabolic processes in rhizosphere SOC accumulation under changing environments. [ABSTRACT FROM AUTHOR]

Summary: Non‐structural carbohydrates (NSCs), as the labile fraction and dominant carbon currency, are essential mediators of plant adaptation to environments. However, whether and how NSC coordinates with plant economic strategy frameworks, particularly the well‐recognized leaf economics spectrums (LES) and root economics space (RES), remains unclear.We examined the relationships between NSC and key plant economics traits in leaves and fine roots across 90 alpine coniferous populations on the Tibetan Plateau, China.We observed contrasting coordination of NSC with economics traits in leaves and roots. Leaf total NSC and soluble sugar aligned with the leaf economic spectrum, conveying a trade‐off between growth and storage in leaves. However, NSC in roots was independent of the root economic spectrum, but highly coordinated with root foraging, with more starch and less sugar in forage‐efficient, thinner roots. Further, NSC‐trait coordination in leaves and roots was, respectively, driven by local temperature and precipitation.These findings highlight distinct roles of NSC in shaping the above‐ and belowground multidimensional economics trait space, and NSC‐based carbon economics provides a mechanistic understanding of how plants adapt to heterogeneous habitats and respond to environmental changes. [ABSTRACT FROM AUTHOR]

In order to analyze the different types of influence of human disturbance on plant communities in the Yellow River wetland and the relevant mechanisms, three wetlands in Zhengzhou section which were respectively affected by agricultural planting, reservoir construction and building construction, were selected after conducting a large number of field investigations. After measuring the plant communities and related environmental factors, redundancy analysis was carried out based on human pressure index evaluation system. The results showed that the whole wetland plant community showed an obvious degradation trend, and the function of productivity maintenance decreased. For the sample land with different types of human disturbance, the severity of human disturbance varied from the disturbance caused by reservoir construction to agricultural planting, and building construction. With intensification of the severity of human disturbance, the similarity coefficients of plant communities in different wetlands declined successively, and the species richness index of wetland in Bird Nature Reserve and Taipingzhuang North wetland decreased by 15. 98% and 37. 05%, respectively, compared with the Taohuayu wetland, indicating that the overall construction of wetland plant communities gradually became simpler. Among the many factors causing wetland degradation, the change of ammonium nitrogen content in soil had a significant negative correlation with species diversity index and species evenness index, and was one of the main reasons for wetland plant degradation. [ABSTRACT FROM AUTHOR]

The interactions between roots and mycorrhizal fungi are critical for our understanding of the multidimensional root economics space. Our knowledge on their relationships comes mainly from arbuscular mycorrhizal (AM) plants, and less is known about how roots are coordinated with ectomycorrhizal (ECM) fungal communities, especially in ECM‐dominated alpine forests that are highly sensitive to climate change worldwide.Here, we investigated the coordination between roots and ECM fungi and their drivers by measuring multiple root traits, ECM fungal composition and environmental factors of 47 coniferous populations across the alpine coniferous forests on the Tibetan Plateau.Our results reveal two independent fine‐root trait dimensions, that is root foraging dimension and root uptake dimension, which are represented by root diameter‐specific root length, root tissue density‐root N concentration. Importantly, the hyphal exploration type based ECM foraging correlated significantly with both root foraging and root uptake dimension. Further, in the low temperature plateau, it is precipitation‐induced changes in soil moisture, soil nutrients and pH that drive the proportion of longer‐distance hyphal exploration types to increase with higher root foraging by higher specific root length, and to decrease with higher uptake by higher root N concentration.Synthesis. The coordination of multidimensional root traits with ECM fungi differs greatly from the well‐recognized pattern in AM plants that mycorrhizal fungi connect predominantly with root foraging and that roots and mycorrhizal fungi are temperature sensitive. These findings provide a new insight for our holistic understanding of how roots and mycorrhizal fungi vary collaboratively and hence driving plant community assembly and responses to the changing climate. [ABSTRACT FROM AUTHOR]

Above‐ground nutrient conservation via resorption processes and below‐ground nutrient acquisition from soils are two important mechanisms for plants to maintain nutrition and ecosystem functions. However, the mechanism by which plants coordinate these two nutrient strategies, especially for ectomycorrhizal (ECM)‐dominated conifers in alpine forests, remains unclear.We investigated the relationships between above‐ground nutrient conservation and below‐ground nutrient acquisition and their environmental drivers by measuring leaf nutrient (i.e. nitrogen [N] and phosphorous [P]) resorption efficiency, resource foraging‐ and uptake‐related root morphological (root diameter [RD], specific root length [SRL]/area [SRA]) and physiological (root tissue density [RTD], root N and P concentration) traits, mycorrhizal colonization rate (MCR), rhizosphere effect on soil N and P cycling, and environmental factors of 40 ECM coniferous populations on the eastern Tibetan Plateau, China.Our results showed that with increasing leaf nutrient (N and P) resorption efficiency, conifers shifted from depending on the 'outsourcing' strategy by mycorrhizal fungi (high MCR) to relying on the 'do‐it‐yourself' strategy of root mining (high rhizosphere effect on N‐ and P‐mining‐related enzyme activities) rather than on root foraging (high SRL and SRA) and preferred more conservative roots (high RTD and low root N and P concentrations). Temperature was the main factor driving a negative relationship of ECM fungi foraging, root uptake and a positive relationship of root mining with leaf nutrient resorption, while precipitation resulted in a decoupled relationship between root foraging and leaf nutrient resorption.Our findings demonstrate temperature‐driven and diverse collaborations (e.g. trade‐off or synergy) between below‐ground nutrient acquisition and above‐ground nutrient conservation strategies in alpine ECM conifers and highlight that the preference for below‐ground nutrient acquisition strategies could influence the above‐ground nutrient utilization strategy. This is insightful for a holistic understanding of the adaptation and responses of alpine forests to climatic change. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Ammonium polyphosphate (APP) is rich in nitrogen (N) and phosphorus (P), which is a raw material for the high-efficiency water-soluble fertilizer production. In this work, the water-soluble APP was directly synthesized using commercial grade-urea phosphate and urea in a microwave reactor. The effects of the molar ratio of urea to phosphate urea (UP), microwave power and reaction time on the quality of APP were also studied. Single-factor experiments indicate that with the optimal conditions: the molar ratio of 0.4, the microwave power of 720 W, and the reaction time of 9 min, the average polymerization degree of APP was 18.91, and the solubility was 6.31 g/100 g H2O. Orthogonal experiment indicates that the order of significant factors for APP production is molar ratio > reaction time > microwave power. Based on the results of the range analysis and analysis of variance, the optimized conditions were found at the molar ratio of 0.6, the microwave power of 720 W, and the reaction time of 9 min, the average polymerization degree of the APP was 21.7 and the solubility was 6.03 g/100 g H2O at 25 °C. The TGA analysis showed that the synthesized APP had a good thermal stability. Its XRD spectrum was the same as the crystalline form I. [ABSTRACT FROM AUTHOR]