
Xiankai LuSouth China Botanical Garden,Chinese Academy of Sciences
Xiankai Lu
PhD
About
141
Publications
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Introduction
Additional affiliations
March 2008 - present
Publications
Publications (141)
Globally increased nitrogen (N) to phosphorus (P) ratios (N/P) affect the structure and functioning of terrestrial ecosystems, but few studies have addressed the variation of foliar N/P over time in subtropical forests. Foliar N/P indicates N versus P limitation in terrestrial ecosystems. Quantifying long-term dynamics of foliar N/P and their poten...
For many years, there has been a prevailing belief that the activity of soil microorganisms in tropical forests is limited by the availability of phosphorus (P). This belief has traditionally found support in experimental research, consistently demonstrating that the addition of P leads to an increase in heterotrophic soil respiration. However, we...
Effective management of macronutrients is pivotal in the optimization and provisioning of ecosystem services in grassland areas, particularly in degraded grasslands. In such instances where mowing and nitrogen (N) fertilization have emerged as predominant management strategies, nutrient management is especially important. However, the precise effec...
High-quality and low-quality root litter had contrasting patterns of mass loss.
Greater litter-derived C was incorporated into soils under high-quality root litter.
Root litter decay rate or litter-derived C were related to soil microbial diversity.
Root litter quality had little effect on soil physicochemical properties.
High root litter quality w...
Feeding an increasingly affluent population is a huge challenge facing global agriculture. In contrast to “large-scale farming” in developed economies (e.g. Europe and the United States), developing countries are dominated by “smallholder farms” relying on traditional farming practices but increasingly with substantial nitrogen overuse leading to s...
We introduce a novel method using a new generative model that automatically learns effective representations of the target and background appearance to detect, segment and track each instance in a video sequence. Differently from current discriminative tracking-by-detection solutions, our proposed hierarchical structural embedding learning can pred...
Lei Liu Wen Xu Zhang Wen- [...]
Xuejun Liu
Growing population and consumption pose unprecedented demands on food production. However, ammonia emissions mainly from food systems increase oceanic nitrogen deposition contributing to eutrophication. Here, we developed a long-term oceanic nitrogen deposition dataset (1970 to 2018) with updated ammonia emissions from food systems, evaluated the i...
Soil macrofauna is an important component of soil biodiversity and plays a key role in soil ecosystem function. Little work, however, has explored how macrofauna may contribute, directly or indirectly, to soil microfauna communities. In this study, we explored the impact of two classes of common soil macrofauna, earthworms (Eisenia foetida) and mil...
Many real-world problems deal with collections of data with missing values, e.g., RNA sequential analytics, image completion, video processing, etc. Usually, such missing data is a serious impediment to a good learning achievement. Existing methods tend to use a universal model for all incomplete data, resulting in a suboptimal model for each missi...
Hui Li Yao Chen Zhe Lu- [...]
Jiangming Mo
The stability of soil organic carbon (SOC) plays a vital role in C sequestration, and largely depends on the availability of soil nitrogen (N) and phosphorus (P). Understanding how different fractions of SOC respond to N and P availability and the underlying microbial mechanism is crucial for mitigating climate changes. Here, we assessed how soil N...
Tropical forests, where the soils are nitrogen (N) rich but phosphorus (P) poor, have a disproportionate influence on global carbon (C) and N cycling. While N deposition substantially alters soil C and N retention in tropical forests, whether P input can alleviate these N-induced effects by regulating soil microbial functions remains unclear. We in...
Soil microbial responses to anthropogenic nitrogen (N) enrichment at the overall community level has been extensively studied. However, the responses of community dynamics and assembly processes of the abundant versus rare bacterial taxa to N enrichment have rarely been assessed. Here, we present a study in which the effects of short- (2 years) and...
There is little known about how understory vegetation affects the soil microbial community assembly, although it exerts strong controls on the soil microbial community composition. We attempted to clarify this question by establishing an experiment in which the understory vegetation was either removed or maintained as controls in a primary tropical...
Deep semi-supervised learning (SSL) methods aim to utilize abundant unlabeled data to improve the seen-class classification. However, in the open-world scenario, collected unlabeled data tend to contain unseen-class data, which would degrade the generalization to seen-class classification. Formally, we define the problem as safe deep semi-supervise...
Video Language Grounding is one of the most challenging cross-modal video understanding tasks. This task aims to localize a target moment semantically corresponding to a given language query in an untrimmed video. Many existing VLG methods rely on the proposal-based framework, despite the dominant performance achieved, they usually focus on interac...
Soil represents the largest terrestrial carbon pool, and it liberates massive amounts of carbon dioxide (CO2) to the atmosphere via respiration, which can influence global carbon cycle. In recent decades, anthropogenic activities have dramatically increased the rates of atmospheric nitrogen (N) deposition worldwide, but our current understanding of...
Background
Two carbon (C) sources are of particular interest for soil organic carbon (SOC) storage under nitrogen (N) deposition: 1) glomalin-related soil protein (GRSP) and 2) microbial residual carbon (MRC) derived from microbial metabolites and residues. Both soil C sources are purported to have long residence times, but their contribution to SO...
Biological invasion is one of the most important factors affecting global biodiversity change, which can adversely affect ecosystem function. However, little is known about the effects of belowground biological invasions on soil ecosystems. In this study, we conducted a field-based mesocosm experiment to observe the effects of exotic and native ear...
Recent frameworks have proposed that division of soil organic matter (SOM) into particulate and mineral-associated organic matter (POM and MAOM) can help us better understand SOM cycling and its responses to increasing atmospheric nitrogen (N) deposition. However, responses of these factions to N deposition with combination of their relative distri...
Sample selection is an effective strategy to mitigate the effect of label noise in robust learning. Typical strategies commonly apply the small-loss criterion to identify clean samples. However, those samples lying around the decision boundary with large losses usually entangle with noisy examples, which would be discarded with this criterion, lead...
Earthworms and their casts act as biocatalysts and regulators of the biotic and abiotic processes in soil ecosystems. However, the relative importance of the presence of earthworms and earthworm casts in affecting other soil biota remains underexplored. In this study, we conducted a manipulative mesocosm experiment in a 30-year-old subtropical broa...
Dissolved organic matter (DOM) plays a key role in forest carbon biogeochemistry by linking soil organic carbon (SOC) sequestration and water fluxes, which is further shaped by elevated atmospheric nitrogen (N) deposition. Although enhanced SOC sequestration was evidenced in tropical forests due to rising N deposition, it remains unclear how long-t...
Melting permafrost mounds in subarctic palsa mires are thawing under climate warming and have become a substantial source of N2O emissions. However, mechanistic insights into the permafrost thaw-induced N2O emissions in these unique habitats remain elusive. We demonstrated that N2O emission potential in palsa bogs was driven by the bacterial reside...
Sample selection is an effective strategy to mitigate the effect of label noise in robust learning. Typical strategies commonly apply the small-loss criterion to identify clean samples. However, those samples lying around the decision boundary with large losses usually entangle with noisy examples, which would be discarded with this criterion, lead...
Elevated nitrogen (N) deposition may further acidify soils in tropical forests. Yet, we have limited evidence on this prediction and it remained unclear how this would affect fine root growth therein. Here, we report responses of fine root biomass, vitality, and chemistry, as well as related soil parameters to eight years of N additions in three tr...
Foliar stable nitrogen (N) isotopes (δ15N) generally reflect N availability to plants and have been used to infer about changes thereof. However, previous studies of temporal trends in foliar δ15N have ignored the influence of confounding factors, leading to uncertainties on its indication to N availability. In this study, we measured foliar δ15N o...
Earthworms and their casts act as biocatalysts and regulators of the biotic and abiotic processes in soil ecosystems. However, the relative importance of the presence of earthworms (direct effects of earthworms) and earthworm casts (indirect effects of earthworms) in affecting other soil biota remains underexplored. In this study, we conducted a fa...
Significance
Agricultural systems are already major forces of ammonia pollution and environmental degradation. How agricultural ammonia emissions affect the spatio-temporal patterns of nitrogen deposition and where to target future mitigation efforts, remains poorly understood. We develop a substantially complete and coherent agricultural ammonia e...
Increasing N input can alter soil nutrient availability and influence plant growth. Previous studies focused on N addition effects on N and P availability, while less on other mineral nutrients. Besides, how N addition duration affects nutrient availability has remained unclear. Based on a simulative N deposition experiment in a typical steppe with...
This paper proposes a novel self-supervised method for one-shot video object segmentation where the object annotations are only provided in the first frame. The current self-supervised video object segmentation approaches are implemented by modeling the pairwise correspondence between the target and reference frames. The pairwise correspondence onl...
A massive rise in atmospheric nitrogen deposition (ND) has threatened ecosystem health through accelerating soil nitrogen (N) cycling rates. While soil microbes serve a crucial function in soil N transformation, it remains poorly understood on how excess ND affects microbial functional populations regulating soil N transformation in tropical forest...
Knowledge about resource limitations faced by soil microorganisms is crucial for understanding ecosystem functions and processes. In recent decades, vegetation restoration has been carried out in the degraded karst areas, leading to the alteration in the status of microbial resource limitation (MRL). However, mechanisms underlying MRL in different...
Weakly supervised video moment retrieval or weakly supervised language moment retrieval aims to search the most relevant moment given a language query. In order to guide the model to capture the most matching video segments with the text description, we design a two-granularity loss function that simultaneously considers both video-level and instan...
Soil fungi play critical roles in ecosystem processes and are sensitive to global changes. Elevated atmospheric nitrogen (N) deposition has been well documented to impact on fungal diversity and community composition, but how the fungal community assembly responds to the duration effects of experimental N addition remains poorly understood. Here, w...
Human activities have disturbed global phosphorus (P) cycling by introducing substantial amounts of P to natural ecosystems. Although natural P gradients and fertilization studies have found that plant community traits are closely related to P availability, it remains unclear how increased P supply affects plant growth and diversity in P-deficient...
A R T I C L E I N F O Keywords: Soil organic carbon storage Light and heavy density fractions Microaggregates Macroaggregates Forest conversion Land-use history A B S T R A C T The impact of human activities on soil carbon (C) storage in tropical forests has aroused wide concern during the past decades, because these ecosystems play a key role in a...
Humid tropical forests are commonly characterized as N-rich but P-deficient. Increased N deposition may drive N saturation and aggravate P limitation in tropical forests. Thus, P addition is proposed to mitigate the negative effects of N deposition by stimulating N cycling. However, little is known regarding the effect of altered N and P supply on...
Anthropogenic elevated nitrogen (N) deposition has an accelerated terrestrial N cycle, shaping soil carbon dynamics and storage through altering soil organic carbon mineralization processes. However, it remains unclear how long-term high N deposition affects soil carbon mineralization in tropical forests. To address this question, we established a...
This paper aims to address few-shot semantic segmentation. While existing prototype-based methods have achieved considerable success, they suffer from uncertainty and ambiguity caused by limited labelled examples. In this work, we propose attentional prototype inference (API), a probabilistic latent variable framework for few-shot semantic segmenta...
Aims
Aboveground plant litter inputs are important sources of soil carbon (C). We aimed to establish how experimentally altered litter inputs affect soil C to 1-m depth across different ecosystems, and over different timeframes.
Methods
We performed a meta-analysis of 237 studies across 248 sites worldwide to assess the influence of treatment magn...
Phosphorus limitation on terrestrial plant growth is being incorporated into Earth system models. The global pattern of terrestrial phosphorus limitation, however, remains unstudied. Here, we examined the global‐scale latitudinal pattern of terrestrial phosphorus limitation by analysing a total of 1068 observations of aboveground plant production r...
Significance
Forest soil carbon (C) storage plays a central role in sequestrating atmospheric CO 2 on timescales from centuries to millennia. However, our current understanding of soil C sequestration in response to N deposition mainly focuses on mid-to-high latitudes in the Northern Hemisphere, where N supply typically constrains forest growth. We...
The effects of deposited nitrogen (N) on forest ecosystems largely depend on the amount of N retained in the ecosystems and its partitioning among ecosystem pools. However, our understanding of the capacity of tropical plantations to retain deposited N is limited. To evaluate the retention of deposited N in a human-disturbed pine plantation in sout...
Plant hydraulic traits have been shown to be sensitive to changes in nitrogen (N) availability in short-term studies largely using seedlings or saplings. The extent and the magnitude of N-sensitivity of the field grown mature trees in long-term experiments, however, are relatively unknown. Here, we investigated responses of leaf water relations and...
Plant diversity has a strong impact on a plethora of ecosystem functions and services, especially ecosystem carbon (C) storage. However, the potential context-dependency of biodiversity effects across ecosystem types, environmental conditions and carbon pools remains largely unknown. In this study, we performed a meta-analysis by collecting data fr...
Background: Soil fungi play critical roles in ecosystem processes and are sensitive to global changes. Elevated atmospheric nitrogen (N) deposition has been well documented to impact on fungal diversity and community composition, but how fungal community assembly respond to short- and long-term simulative N deposition remains poorly understood. Her...
We investigated the impacts of 14-year continuous N addition on activities of arylsulfatase (AS) and phosphodiesterase (PDE), which catalyze soil organic sulfur (S) and phosphorus (P), respectively. The response of AS to N addition was compared with that of C- and N-acquiring enzymes, i.e., β-1,4-glucosidase (BG), β-D-cellobiohydrolase (CBH), β-1,4...
Key message
Nitrogen addition during 4 years to the canopy of Castanopsis chinensis (Sprengel) Hance promoted xylem formation, mainly by increasing radial growth during the early growth season.
ContextIncreased atmospheric nitrogen (N) deposition caused by intensive anthropogenic activities resulted in inconsistent effects on the xylem formation of...
A mechanistic understanding of plant photosynthetic response is needed to reliably predict changes in terrestrial carbon (C) gain under conditions of chronically elevated atmospheric nitrogen (N) deposition. Here, using 2,683 observations from 240 journal articles, we conducted a global meta‐analysis to reveal effects of N addition on 14 photosynth...
Purpose
Phosphorus (P) addition could largely alter soil microbial activity. However, effects of long-term P addition on soil extracellular enzyme activity are not well understood in tropical forests.
Materials and methods
To address this question, we measured absolute activities (activity per unit of dry soil) and specific activities (activity pe...
Phosphorus (P) limitation of aboveground plant production is usually assumed to occur in tropical regions but rarely elsewhere. Here we report that such P limitation is more widespread and much stronger than previously estimated. In our global meta-analysis, almost half (46.2%) of 652 P-addition field experiments reveal a significant P limitation o...
Enzai Du Xiankai Lu Di Tian- [...]
Nan Xia
Anthropogenic nitrogen (N) deposition, mainly driven by reactive N emissions from agricultural and industrial activities, has been enhanced dramatically in China. The enhancement of N deposition has aroused increasing concerns about its effects on ecosystem health and function. Forest covers more than one fifth of the national land area in China an...
Differences in nitrogen (N) acquisition patterns between plant species are often reflected in the natural 15N isotope ratios (δ15N) of the plant tissues, however, such differences are poorly understood for co-occurring plants in tropical and subtropical forests. To evaluate species variation in N acquisition traits, we measured leaf N concentration...
Nitrogen (N) deposition is a component of global change that has considerable impact on belowground carbon
Soil organic carbon (SOC) plays critical roles in stabilizing atmospheric CO 2 concentration, but the mechanistic controls on the amount and distribution of SOC on global scales are not well understood. In turn, this has hampered the ability to model global C budgets and to find measures to mitigate climate change. Here, based on the data from a la...
The prevailing paradigm for soil microbial activity in tropical forests is that microbial activity is limited by phosphorus (P) availability. Thus, exogenous P addition should increase rates of organic matter decomposition. Studies have also confirmed that soil respiration is accelerated when P is added experimentally. However, we hypothesize that...
Because potassium (K) is a rock-derived essential element that can be depleted in highly-weathered tropical soils, K availability may limit some portion of soil microbial activity in tropical forest ecosystems. In this paper we tested if K limits microbial activity in the condition of sufficient labile C supply. An incubation experiment was perform...
Deep regression tracker assigns soft Gaussian labels to the dense samples drawn on convolution feature map. It has become a popular tracking framework as its intrinsic end-to-end learning characteristics. In this paper, we analyze the channel-wise information of convolution features in deep regression tracking and propose an effective channel-aware...