Effect of nitrogen and phosphorus addition on leaf nutrient concentrations and nutrient resorption efficiency of two dominant alpine grass species

Abstract Aims Leaf nutrient resorption is sensitive to changes in soil nutrients. However, the effects of N deposition on nutrient resorption efficiency (NuRE) in plant macro-nutrients remain unclear. Poplar (Populus deltoids) is one of the most extensively cultivated hardwood species worldwide. We explored general patterns and dominant drivers of NuRE and stoichiometry of poplar plantations in response to N addition. Methods We conducted a 4-year N-addition experiment to explore NuRE and stoichiometric responses to N addition in two poplar (Populus deltoids) plantations (8- and 12-year-old stands) in a coastal region of eastern China. We measured soil and foliar (green and senesced leaves) concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) for a series of N addition treatments including N0 (0 kg N ha ‒1 yr ‒1), N1 (50 kg N ha ‒1 yr ‒1), N2 (100 kg N ha ‒1 yr ‒1), N3 (150 kg N ha ‒1 yr ‒1), and N4 (300 kg N ha ‒1 yr ‒1). Important Findings Consistent for (both) 8- and 12-year-old stands, N addition did not affect the NuRE and stoichiometry (with the exception of CaRE and CaRE:MgRE ratio). NRE-PRE scaling slopes were consistently less than 1.0 under N addition. These results suggest that NRE generally decouples from PRE within each N treatment. Moreover, these results point to robust control of green leaf nutritional status on nutrient resorption processes as indicated by the positive relationships between nutrient resorption efficiency and green leaf nutrient concentrations. Our findings provided a direct evidence that growth in 12-year-old poplar plantations was N-limited in a coastal region of eastern China.

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Mangrove species maintains constant nutrient resorption efficiency under eutrophic conditions

Journal of Tropical Ecology ◽

10.1017/s0266467419000336 ◽

2019 ◽

Vol 36 (1) ◽

pp. 36-38

Author(s):

Lili Wei ◽

Shuh-Ji Kao ◽

Chaoxiang Liu

Keyword(s):

Nutrient Availability ◽

Nutrient Enrichment ◽

Nutrient Resorption ◽

Conservation Strategy ◽

Nutrient Concentrations ◽

Resorption Efficiency ◽

Mangrove Species ◽

Nutrient Resorption Efficiency ◽

Black Mangrove ◽

Nutrient Conservation

AbstractMangrove species have developed nutrient conservation mechanisms to adapt to oligotrophic intertidal environments. However, nutrient enrichment occurs worldwide, particularly in estuarine and coastal regions. Mangrove species may change their adaptive strategies if nutrient availability increases substantially. To understand how nutrient resorption (a major nutrient conservation strategy) responds to nutrient enrichment, a common mangrove species in China, Aegiceras corniculatum (black mangrove), was selected, and saplings were cultivated in nutrient-enriched soils. After one year, neither N nor P resorption efficiency showed significant variations with nutrient availability and there was no difference between N and P resorption efficiency. Overall, nutrient resorption efficiency of A. corniculatum remained at ∼40%, lower than the global average levels of evergreen plants (∼50%), indicating incomplete resorption of nutrients. Incomplete resorption was also evidenced by the nutrient concentrations, resorption proficiency and N: P ratio of plant leaves. Collectively, these results indicate that black mangrove can maintain constant nutrient resorption efficiency under eutrophic conditions.

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Nitrogen and Phosphorus Resorption in Planted Forests Worldwide

Forests ◽

10.3390/f10030201 ◽

2019 ◽

Vol 10 (3) ◽

pp. 201 ◽

Cited By ~ 12

Author(s):

Dalong Jiang ◽

Qinghong Geng ◽

Qian Li ◽

Yiqi Luo ◽

Jason Vogel ◽

...

Keyword(s):

Nutrient Use Efficiency ◽

Nutrient Resorption ◽

Green Leaf ◽

Mean Annual Precipitation ◽

Nutrient Concentrations ◽

Planted Forests ◽

Climate Zones ◽

Functional Types ◽

Precipitation Regimes ◽

Leaf Nutrient Concentrations

Nutrient resorption from senescing leaves is one of the plants’ essential nutrient conservation strategies. Parameters associated with resorption are important nutrient-cycling constraints for accurate predictions of long-term primary productivity in forest ecosystems. However, we know little about the spatial patterns and drivers of leaf nutrient resorption in planted forests worldwide. By synthesizing results of 146 studies, we explored nitrogen (N) and phosphorus (P) resorption efficiency (NRE and PRE) among climate zones and tree functional types, as well as the factors that play dominant roles in nutrient resorption in plantations globally. Our results showed that the mean NRE and PRE were 58.98% ± 0.53% and 60.21% ± 0.77%, respectively. NRE significantly increased from tropical to boreal zones, while PRE did not significantly differ among climate zones, suggesting differential impacts of climates on NRE and PRE. Plant functional types exert a strong influence on nutrient resorption. Conifer trees had higher PRE than broadleaf trees, reflecting the adaptation of the coniferous trees to oligotrophic habitats. Deciduous trees had lower PRE than evergreen trees that are commonly planted in P-limited low latitudes and have long leaf longevity with high nutrient use efficiency. While non-N-fixing trees had higher NRE than N-fixing trees, the PRE of non-N-fixing trees was lower than that of N-fixing trees, indicating significant impact of the N-fixing ability on the resorption of N and P. Our multivariate regression analyses showed that variations in NRE were mainly regulated by climates (mean annual precipitation and latitude), while variations in PRE were dominantly controlled by green leaf nutrient concentrations (N and P). Our results, in general, suggest that the predicted global warming and changed precipitation regimes may profoundly affect N cycling in planted forests. In addition, green leaf nutrient concentrations may be good indicators for PRE in planted forests.

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Different responses of plant N and P resorption to overgrazing in three dominant species in a typical steppe of Inner Mongolia, China

PeerJ ◽

10.7717/peerj.9915 ◽

2020 ◽

Vol 8 ◽

pp. e9915

Author(s):

Zhen Wang ◽

Saheed Olaide Jimoh ◽

Xiliang Li ◽

Baoming Ji ◽

Paul C. Struik ◽

...

Keyword(s):

Plant Species ◽

Nutrient Resorption ◽

Grass Species ◽

Resorption Efficiency ◽

Typical Steppe ◽

P Concentration ◽

N Resorption ◽

Senesced Leaves ◽

Dominant Grass ◽

Leaf N

Nutrient resorption from senesced leaves is an important mechanism for nutrient conservation in plants. However, little is known about the effect of grazing on plant nutrient resorption from senesced leaves, especially in semiarid ecosystems. Here, we evaluated the effects of grazing on N and P resorption in the three most dominant grass species in a typical steppe in northern China. We identified the key pathways of grazing-induced effects on N and P resorption efficiency. Grazing increased N and P concentrations in the green leaves of Leymus chinensis and Stipa grandis but not in Cleistogenes squarossa. Both L. chinensis and S. grandis exhibited an increasing trend of leaf N resorption, whereas C. squarrosa recorded a decline in both leaf N and P resorption efficiency under grazing. Structural equation models showed that grazing is the primary driver of the changes in N resorption efficiency of the three dominant grass species. For L. chinensis, the P concentration in green and senesced leaves increased the P resorption efficiency, whereas the senesced leaf P concentration played an important role in the P resorption efficiency of C. squarrosa. Grazing directly drove the change in P resorption efficiency of S. grandis. Our results suggest that large variations in nutrient resorption patterns among plant species depend on leaf nutritional status and nutrient-use strategies under overgrazing, and indicate that overgrazing may have indirect effects on plant-mediated nutrient cycling via inducing shifts in the dominance of the three plant species.

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