scholarly journals Historic Grazing Enhances Root-Foraging Plasticity and Assimilation But Not Absorbability For Nitrogen of Clonal Offspring in Leymus Chinensis

2021 ◽  
Author(s):  
Xiliang Li ◽  
Ningning Hu ◽  
Jingjing Yin ◽  
Weibo Ren ◽  
Ellen Fry
Keyword(s):  
N Uptake ◽  
Utilization Efficiency ◽  
Leymus Chinensis ◽  
Legacy Effects ◽  
Asexual Propagation ◽  
Legacy Effect ◽  
Grassland Plants ◽  
N Assimilation ◽  
Assimilation Capacity

Abstract Aims Plants with a history of overgrazing show trait-mediated legacy effects. These legacy effects strongly influence growth dynamics and stress tolerance of grassland plants, thus impacting ecosystem functioning. Long-term overgrazing has strong effects on plant growth and carbon assimilation via asexual propagation. However, the links between nitrogen (N) cycling and grazing-induced plant legacy effects are largely unknown.Methods We tested the strength of legacy effects of long-term overgrazing on N metabolism in the clonal plant Leymus chinensis, and its associated changes at the physiological and molecular levels. These tests were conducted in both field and greenhouse experiments.Results The clonal offspring of overgrazed L. chinensis were significantly smaller than the control offspring, with lower individual N uptake and N utilization efficiency, indicating that the N dynamics were impacted by plant legacy effects. The response ratios of root traits to N patches in the clonal offspring of overgrazed L. chinensis were significantly higher than those of the control, indicating that root nutrient foraging plasticity increased to cope with grazing-induced N heterogeneity. Moreover, the observed plant legacy effects slightly decreased N absorbability in roots but significantly increased N assimilation capacity, by increasing N resorption efficiency in particular, with biotic stress memory activated at the enzymatic and transcriptional levels.Conclusions We propose that multigenerational exposure of perennial plants to herbivore foraging can produce a legacy effect on nutrient uptake, which offers insights into the potential resilience of grasslands to overgrazing.

scholarly journals Shoot–Root Interplay Mediates Defoliation-Induced Plant Legacy Effect

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiliang Li ◽  
Zhen Zhang ◽  
Fenghui Guo ◽  
Junjie Duan ◽  
Juan Sun
Keyword(s):  
Plant Traits ◽  
Perennial Grass ◽  
Root Traits ◽  
Leymus Chinensis ◽  
Shoot Biomass ◽  
Grassland Species ◽  
Legacy Effect ◽  
Trait Plasticity ◽  
Grassland Plants ◽  
Defoliation Treatment

Shoot defoliation by grazers or mowing can affect root traits of grassland species, which may subsequently affect its aboveground traits and ecosystem functioning (e.g., aboveground primary production). However, experimental evidence for such reciprocal feedback between shoots and roots is limited. We grew the perennial grass Leymus chinensis–common across the eastern Eurasian steppe–as model species in a controlled-hydroponics experiment, and then removed half of its shoots, half of its roots, or a combination of both. We measured a range of plant aboveground and belowground traits (e.g., phenotypic characteristics, photosynthetic traits, root architecture) in response to the shoot and/or root removal treatments. We found the regenerated biomass was less than the lost biomass under both shoot defoliation and root severance, generating a under-compensatory growth. Root biomass was reduced by 60.11% in the defoliation treatment, while root severance indirectly reduced shoot biomass by 40.49%, indicating a feedback loop between shoot and root growth. This defoliation-induced shoot–root feedback was mediated by the disproportionate response and allometry of plant traits. Further, the effect of shoot defoliation and root severance on trait plasticity of L. chinensis was sub-additive. That is, the combined effects of the two treatments were less than the sum of their independent effects, resulting in a buffering effect on the existing negative influences on plant persistence by increased photosynthesis. Our results highlight the key role of trait plasticity in driving shoot–root reciprocal feedbacks and growth persistence in grassland plants, especially perennial species. This knowledge adds to earlier findings of legacy effects and can be used to determine the resilience of grasslands.

scholarly journals Enhancement of root architecture and nitrate transporter gene expression improves plant growth and nitrogen uptake under long-term low-nitrogen stress in barley (Hordeum vulgare L.) seedlings

2021 ◽  
Author(s):  
Runhong Gao ◽  
Guimei Guo ◽  
Hongwei Xu ◽  
Zhiwei Chen ◽  
Yingbo Li ◽  
...  
Keyword(s):  
Plant Growth ◽  
N Uptake ◽  
Dry Weight ◽  
Nitrate Transporter ◽  
Hordeum Vulgare L ◽  
N Accumulation ◽  
Influx Rate ◽  
Expression Levels ◽  
N Assimilation

AbstractOver application of nitrogen (N) fertilizers to crops ultimately causes N pollution in the ecosphere. Studying the response of plant growth and N uptake to low-N stress may aid in elucidating the mechanism of low N tolerance in plants and developing crop cultivars with high nitrogen use efficiency (NUE). In this study, a high-NUE mutant line A9-29 and the wild-type barley cultivar Hua30 were subjected to hydroponic culture with high and low N supply, and the dry weight, N accumulation, root morphology, and expression levels of the potential genes involved in nitrate uptake and assimilation were measured at seedling stage. The results showed that under low-N conditions, A9-29 had a higher dry weight, N content, N influx rate and larger root uptake area than did Hua30. Under long-term low-N stress, compared with Hua30, A9-29 demonstrated higher expression of the HvNRT2/3 genes, especially HvNRT2.1, HvNRT2.5, and HvNRT3.3. Similarly, the expression levels of N assimilation genes including HvNIA1, HvNIR1, HvGS1_1, HvGS1_3, and HvGLU2 increased significantly in A9-29. Taken together, our results suggested that the larger root area and the upregulation of nitrate transporter and assimilation genes may contribute to stronger N uptake capacity for plant growth and N accumulation in responding to long-term low-N stress. These findings may aid in understanding the mechanism of low N tolerance and developing barley cultivars with high-NUE.

scholarly journals Legacy effects of historical grazing alter leaf stomatal characteristics in progeny plants

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9266
Author(s):  
Jingjing Yin ◽  
Xiliang Li ◽  
Huiqin Guo ◽  
Jize Zhang ◽  
Lingqi Kong ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Stomatal Conductance ◽  
Abc Transporter ◽  
Stomatal Density ◽  
Expression Patterns ◽  
Legacy Effects ◽  
Legacy Effect ◽  
Grassland Plants ◽  
Leaf Surfaces ◽  
Stomatal Traits

Grazing, one of the primary utilization modes of grassland, is the main cause of grassland degradation. Historical overgrazing results in dwarf phenotype and decreased photosynthesis of perennial plants. However, it remains unknown what the mechanism underlying of this legacy effect is, and the role of stomata in the resulting decreased photosynthesis also remains unclear. To address these questions, differences in stomatal density, length and width on both adaxial and abaxial epidermis were compared between overgrazing and ungrazed Leymus chinensis offspring by using rhizome buds cultivated in a greenhouse, and the correlation between photosynthetic capacity and stomatal behavior was also investigated. Our results showed that historical grazing significantly impacted phenotype, photosynthesis and stomatal traits of L. chinensis. The offspring plants taken from overgrazed parents were dwarfed compared to those taken from ungrazed parents, and the photosynthesis and stomatal conductance of plants with a grazing history decreased by 28.6% and 21.3%, respectively. In addition, stomatal density and length on adaxial and abaxial leaf surfaces were significantly increased; however, stomatal width on abaxial leaf surfaces of overgrazed L. chinensis was significantly decreased compared with ungrazed individuals. Moreover, the expression patterns of eight genes related to stomatal regulation were tested: seven were down-regulated (2–18 times) and one was up-regulated (three times). Genes, involved in ABC transporter and receptor-like serine/threonine protein kinase were down-regulated. These results suggest that legacy effects of historical grazing affect the stomatal conductance by decreasing the stomatal width in progeny plants, which thus results in lower photosynthesis. Furthermore, changes of stomatal traits and function were regulated by the inhibition of ABC transporter and serine/threonine protein kinase. These findings are helpful for future exploration of the possible mechanisms underlying the response of grassland plants to long-term overgrazing.

scholarly journals The Plant Growth-Promoting Fungus MF23 (Mycena sp.) Increases Production of Dendrobium officinale (Orchidaceae) by Affecting Nitrogen Uptake and NH4+ Assimilation

2021 ◽  
Vol 12 ◽  
Author(s):  
Tingting Shan ◽  
Lisi Zhou ◽  
Bing Li ◽  
Xiaomei Chen ◽  
Shunxing Guo ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Seedling Recruitment ◽  
N Uptake ◽  
Ammonium Transporter ◽  
Dendrobium Officinale ◽  
Amino Acid Transporters ◽  
N Assimilation ◽  
Plant Growth Promoting ◽  
N Metabolism ◽  
Assimilation Capacity

Dendrobium officinale Kimura et Migo is a traditional and scarce medicinal orchid in China. Mycorrhizal fungi could supply nitrogen (N) to orchids for seed germination and seedling recruitment. However, the N transport mechanism between orchids and the fungus is poorly understand. Early studies found that the fungus MF23 (Mycena sp.) could promote the growth of D. officinale. To better dissect the molecular interactions involved in N transport between D. officinale and MF23, transcriptome and metabolome analyses were conducted on conventional and mycorrhizal cultivations of D. officinale. Moreover, validation tests were carried out in the greenhouse to measure net fluxes of NO3− and NH4+ of roots by a non-invasive micro-test technology (NMT), determine N assimilation enzyme activity by the ELISA, and analyze the expression level of differentially expressed genes (DEGs) of N transporters and DEGs involved in N metabolism by RT-qPCR. Combined transcriptome and metabolome analyses showed that MF23 may influence N metabolism in D. officinale. The expression of DoNAR2.1 (nitrate transporter-activating protein), DoAMT11 (ammonium transporter), DoATFs (amino acid transporters), DoOPTs (oligopeptide transporters), and DoGDHs (glutamate dehydrogenases) in symbiotic D. officinale was upregulated. NMT results showed a preference for NH4+ in D. officinale and indicated that MF23 could promote the uptake of NO3− andNH4+, especially for NH4+. ELISA results showed that MF23 could increase the activity of glutamine synthetase (GS) and glutamate dehydrogenase. This study suggested that MF23 increases the production of D. officinale by affecting N uptake and NH4+ assimilation capacity.

scholarly journals Biochar and urease inhibitor mitigate NH3 and N2O emissions and improve wheat yield in a urea fertilized alkaline soil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Khadim Dawar ◽  
Shah Fahad ◽  
M. M. R. Jahangir ◽  
Iqbal Munir ◽  
Syed Sartaj Alam ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Grain Yield ◽  
Block Design ◽  
N Uptake ◽  
Nitrous Oxide Emissions ◽  
N2o Emissions ◽  
Urease Inhibitor ◽  
Alkaline Soil ◽  
Total N ◽  
N Assimilation

AbstractIn this study, we explored the role of biochar (BC) and/or urease inhibitor (UI) in mitigating ammonia (NH3) and nitrous oxide (N2O) discharge from urea fertilized wheat cultivated fields in Pakistan (34.01°N, 71.71°E). The experiment included five treatments [control, urea (150 kg N ha−1), BC (10 Mg ha−1), urea + BC and urea + BC + UI (1 L ton−1)], which were all repeated four times and were carried out in a randomized complete block design. Urea supplementation along with BC and BC + UI reduced soil NH3 emissions by 27% and 69%, respectively, compared to sole urea application. Nitrous oxide emissions from urea fertilized plots were also reduced by 24% and 53% applying BC and BC + UI, respectively, compared to urea alone. Application of BC with urea improved the grain yield, shoot biomass, and total N uptake of wheat by 13%, 24%, and 12%, respectively, compared to urea alone. Moreover, UI further promoted biomass and grain yield, and N assimilation in wheat by 38%, 22% and 27%, respectively, over sole urea application. In conclusion, application of BC and/or UI can mitigate NH3 and N2O emissions from urea fertilized soil, improve N use efficiency (NUE) and overall crop productivity.

scholarly journals Impact of Mycorrhization on Phosphorus Utilization Efficiency of Acacia gummifera and Retama monosperma under Salt Stress

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 611
Author(s):  
Abdessamad Fakhech ◽  
Martin Jemo ◽  
Najat Manaut ◽  
Lahcen Ouahmane ◽  
Mohamed Hafidi
Keyword(s):  
Salt Stress ◽  
Root Growth ◽  
N Uptake ◽  
P Uptake ◽  
Utilization Efficiency ◽  
Legume Species ◽  
Growth Responses ◽  
Phosphorus Utilization ◽  
Phosphorus Utilization Efficiency ◽  
Shoot And Root Growth

The impact of salt stress on the growth and phosphorus utilization efficiency (PUE) of two leguminous species: Retama monosperma and Acacia gummifera was studied. The effectiveness of arbuscular mycorrhizal fungi (AMF) to mitigate salt stress was furthermore assessed. Growth, N and P tissue concentrations, mycorrhizal root colonization frequency and intensity, and P utilization efficiency (PUE) in the absence or presence of AMF were evaluated under no salt (0 mM L−1) and three salt (NaCl) concentrations of (25, 50 and 100 mM L−1) using a natural sterilized soil. A significant difference in mycorrhizal colonization intensity, root-to-shoot ratio, P uptake, PUE, and N uptake was observed between the legume species. Salt stress inhibited the shoot and root growth, and reduced P and N uptake by the legume species. Mycorrhizal inoculation aided to mitigate the effects of salt stress with an average increase of shoot and root growth responses by 35% and 32% in the inoculated than in the non-inoculated A. gummifera treatments. The average shoot and root growth responses were 37% and 45% higher in the inoculated compared to the non-inoculated treatments of R. monosperma. Average mycorrhizal shoot and root P uptake responses were 66% and 68% under A. gummifera, and 40% and 95% under R. monosperma, respectively. Mycorrhizal inoculated treatments consistently maintained lower PUE in the roots. The results provide insights for further investigations on the AMF conferred mechanisms to salt stress tolerance response by A. gummifera and R. monosperma, to enable the development of effective technologies for sustainable afforestation and reforestation programs in the Atlantic coast of Morocco.

Long-term effect of cropping system and nitrogen and phosphorus fertilizer on production and nitrogen economy of grain crops in a Brown Chernozem

2005 ◽  
Vol 85 (1) ◽  
pp. 81-93 ◽  
Author(s):  
C. A. Campbell ◽  
R. P. Zentner ◽  
F. Selles ◽  
P. G. Jefferson ◽  
B. G. McConkey ◽  
...  
Keyword(s):  
Water Use ◽  
Environmental Sustainability ◽  
Crop Production ◽  
N Uptake ◽  
Yield Response ◽  
Average Response ◽  
Nitrogen And Phosphorus ◽  
N Yield ◽  
P Fertilizer

Assessment of the long-term impact of fertilizers and other management factors on crop production and environmental sustainability of cropping systems in the semi-arid Canadian prairies is needed. This paper discusses the long-term influence of N and P fertilizers on crop production, N uptake and water use of hard red spring wheat (Triticum aestivum L.), and the effect of the preceding crop type [flax (Linum usitatissimum L.) and fall rye (Secale cereale L.)] on wheat grown on a medium-textured, Orthic Brown Chernozem at Swift Current, Saskatchewan. We analysed 36 yr of results (1967–2002) from eight crop rotation-fertility treatments: viz., fallow-wheat receiving N and P (F-W, N + P), three F-W-W treatments fertilized with (i) N + P, (ii) P only, and (iii) N only; two other 3-yr mixed rotations with N + P (i) F-flax-W (F-Flx-W) and (ii) F-fall rye-W (F-Rye-W); and two continuous wheat rotations (Cont W), one receiving N + P and the other only P. Growing season weather conditions during the 36-yr period were near the long-term mean, but the first 22 yr were generally drier than normal while the last 14 yr (1989–2002) had average to above-average growing conditions. This was partly responsible for grain and N yield being greater in the latter period than in the first 22 yr. The 36-yr average response of wheat grown on fallow to P fertilizer was 339 kg ha-1, while the response to N fertilizer over this period was only 123 kg ha-1. The 36-yr average response of wheat grown on stubble to N was 344 kg ha-1 for F-W-(W) and 393 kg ha-1 for Cont W. Neither flax nor fall rye influenced the yield response of the following wheat crops. Annualized grain production for F-W (N + P), F-W-W (+ N) and F-W-W (+ P) rotations were similar (1130 kg ha-1 yr-1); this was about 15% lower than for F-W-W (N + P), 40% lower than for Cont W (N + P), and 5% lower than for Cont W (+ P). Annualized aboveground N yield for Cont W (N + P) was 57% higher than for Cont W (+ P). Regressions were developed relating straw to grain yields for wheat, flax and fall rye. The amount of NO3-N left in the soil was directly related to amount of N applied and inversely to N removed in the crop. Thus, F-(W)-W (+ N) left about 28% more NO3-N in the rooting zone than F-(W)-W (N + P), while F-W-(W) (N + P) left 20% more than F-W-(W) (+ P), and Cont W (N + P) left 39% more than Cont W (+ P). F-Rye-W (N + P) left much less NO3-N in the soil than any other fallow-containing system and similar amounts to Cont W (N + P). Key words: Yields, grain protein, N and P fertilizer, straw/grain regressions, water use, soil nitrate

Sign in / Sign up

Export Citation Format

Share Document