Allocation and morphological responses to resource manipulations are unlikely to mitigate shade intolerance in Houstonia montana, a rare southern Appalachian herb

2007 ◽  
Vol 85 (10) ◽  
pp. 976-985 ◽  
Author(s):  
Amy C. Euliss ◽  
Melany C. Fisk ◽  
S. Coleman McCleneghan ◽  
Howard S. Neufeld
Keyword(s):  
Nitrogen Availability ◽  
Carbon Allocation ◽  
Plant Biomass ◽  
Specific Root Length ◽  
Mycorrhizal Colonization ◽  
N Availability ◽  
Low Light ◽  
Southern Appalachian ◽  
Aboveground Growth ◽  
Root:Shoot Ratios

High light requirements limit the distribution of several rare plant species endemic to the southern Appalachian region. We studied the influence of light and nitrogen availability on carbon allocation and morphology in one of these species, Houstonia montana Small. Insights into growth and nutrition of H. montana are needed for predicting how it will respond to ongoing changes in its environment associated with atmospheric nitrogen deposition and resulting from succession and (or) management of grassy-bald habitats in which it occurs. We hypothesized that low light constrains belowground allocation, and that elevated N availability reduces limitations to aboveground growth at low light. We tested growth and mycorrhizal colonization of H. montana in response to interactions of light and N availability in a greenhouse experiment. Shade reduced plant biomass, root:shoot ratios, and mycorrhizal colonization, and increased specific leaf area (area/mass). Elevated N reduced root:shoot ratios and mycorrhizal colonization. Under low light, N addition increased specific root length (length/mass) and foliar chlorophyll. We found support for the hypotheses that low light and high N reduce belowground allocation in H. montana. However, we did not find that high N significantly alleviates limitation to plant growth in the shade, despite changes in allocation, morphology, and chemistry that were consistent with more efficient use of C for aboveground growth. Thus, variation in the soil N availability is unlikely to have a marked effect on the ability of H. montana to tolerate shade in its native habitat.

Soil and plant response to wellsite rehabilitation on native prairie in southeastern Alberta, Canada

2003 ◽  
Vol 83 (5) ◽  
pp. 507-519 ◽  
Author(s):  
A. M. Hammermeister ◽  
M. A. Naeth ◽  
J. J. Schoenau ◽  
V. O. Biederbeck
Keyword(s):  
Biomass Production ◽  
Plant Uptake ◽  
Nitrogen Availability ◽  
Carbon Allocation ◽  
Petroleum Industry ◽  
N Availability ◽  
Higher Plant ◽  
Available N ◽  
Native Prairie ◽  
Low Diversity

Rehabilitation of disturbed native prairie is a challenge facing many in the petroleum industry, with implications for prairie ecology and productivity. The purpose of this research was to examine the relative influence of four rehabilitation strategies on biogeochemical processes (i.e., nitrogen availability, plant uptake of nitrogen, biomass production, carbon allocation, and soil biological activity). Seven petroleum wellsites were selected on Chernozemic and Solonetzic soils in southeastern Alberta. Undisturbed native prairie was compared with four seeding treatments: not seeded, a low diversity seed mix commonly used by industry, a low diversity mix of species more typically dominant in native prairie, and a diverse seed mix. Flux of NO3− and NH4+were measured in situ using ion exchange membranes. Soil total C and N were lower and available N higher as a result of disturbance. In the seeded treatments, biomass production was higher and soil nitrogen flux was lower due to higher plant uptake than in the unseeded treatment. Higher initial N availability favoured species with rapid growth and colonization rates, particularly Agropyron dasystachyum [(Hook.) Scribn.] and Agropyron trachycaulum [(Link) Malte]. Seed mix composition and species attributes were deemed to have greater influence on N cycling and biomass production than seed mix diversity. Key words: Nitrogen cycling, plant competition, secondary succession, wheatgrass, biodiversity, prairie

scholarly journals Nitrogen availability controls plant carbon storage with warming

2021 ◽  
Author(s):  
Guiyao Zhou ◽  
César Terrer ◽  
Bruce Hungate ◽  
Natasja van Gestel ◽  
Xuhui Zhou ◽  
...  
Keyword(s):  
Nitrogen Availability ◽  
Plant Biomass ◽  
Meta Analysis ◽  
C:N Ratio ◽  
Belowground Biomass ◽  
Climate Projections ◽  
N Availability ◽  
Soil N ◽  
C Storage ◽  
Induced Changes

Abstract Plants may slow global warming through enhanced growth, because increased levels of photosynthesis stimulate the land carbon (C) sink. However, the key drivers determining responses of plants to warming remain unclear, causing uncertainty in climate projections. Using meta- analysis, we show that the effect of experimental warming on plant biomass is best explained by soil nitrogen (N) availability. Warming-induced changes in total, aboveground and belowground biomass all positively correlated with soil C:N ratio, an indicator of soil N availability. In factorial N × warming experiments, warming increased plant biomass more strongly under low N than under high N availability. Together, these results suggest that warming stimulates plant C storage most strongly in ecosystems where N limits plant growth. Thus, incorporating the soil N status of ecosystems into Earth system models may improve predictions of future carbon-climate feedbacks.

scholarly journals Nitrogen availability controls plant carbon storage with warming

2021 ◽  
Author(s):  
Guiyao Zhou ◽  
César Terrer ◽  
Bruce Hungate ◽  
Natasja van Gestel ◽  
Xuhui Zhou ◽  
...  
Keyword(s):  
Nitrogen Availability ◽  
Plant Biomass ◽  
Meta Analysis ◽  
C:N Ratio ◽  
Climate Projections ◽  
N Availability ◽  
Experimental Warming ◽  
C Storage ◽  
Model Predictions ◽  
Key Drivers

Abstract Plants may slow global warming through enhanced growth, thereby stimulating the land carbon (C) sink. However, the key drivers determining responses of plants to warming remain unclear, causing uncertainty in climate projections. Using meta-analysis, we show that the effect of experimental warming on plant biomass is best explained by soil C:N ratio, an indicator of soil nitrogen (N) availability. Our results suggest that warming stimulates plant C storage most strongly in ecosystems where N limits plant growth, and may inform model predictions of warming may improve by considering spatially explicitly .

scholarly journals Lower Nitrogen Availability Enhances Resistance to Whiteflies in Tomato

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1096
Author(s):  
Sreedevi Ramachandran ◽  
Sylvie Renault ◽  
John Markham ◽  
Jaime Verdugo ◽  
Marta Albornoz ◽  
...  
Keyword(s):  
Large Scale ◽  
Nitrogen Availability ◽  
Crop Yields ◽  
Fruit Production ◽  
N Availability ◽  
Significant Drop ◽  
Tomato Production ◽  
Trade Off ◽  
Pest Infestation ◽  
Root:Shoot Ratios

Soil nitrogen (N) supplementation via fertilizers may increase crop yields substantially. However, by increasing tissue N content, added N can make plants more attractive to herbivores, effectively reducing their resistance to herbivores (ability to avoid herbivore damage). In turn, greater pest infestation may cause more severe reductions in fruit production than a moderate N scarcity. In this study, we tested whether lower N supplementation results in greater resistance to whiteflies and lower fruit production in four tomato varieties. We assessed the effects of N availability on tolerance to herbivores (degree to which fitness is affected by damage) and tested for the long-hypothesized trade-off between resistance and tolerance. Plants grown at half of an agronomically recommended amount of N had greater resistance without a significant drop in fruit production. Tomato varieties differed in resistance and tolerance to whiteflies, and showed a clear trade-off between these modes of defense. Root:shoot ratios were greater at lower N, but had no clear relation to tolerance. We estimated that the economic benefit of decreasing N addition almost fully compensates for losses due to lower tomato production. Additionally, lower fertilization rates would contribute to reduce environmental costs of large-scale use of agrochemicals.

Soil nitrogen availability influences seasonal carbon allocation patterns in sugar maple (Acersaccharum)

1992 ◽  
Vol 22 (4) ◽  
pp. 447-456 ◽  
Author(s):  
Marianne K. Burke ◽  
Dudley J. Raynal ◽  
Myron J. Mitchell
Keyword(s):  
Fine Roots ◽  
Sugar Maple ◽  
Nitrogen Availability ◽  
Fine Root ◽  
Carbon Allocation ◽  
Root Production ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability ◽  
Allocation Patterns

The influence of soil N availability on growth, on seasonal C allocation patterns, and on sulfate-S content in sugar maple seedlings (Acersaccharum Marsh.) was tested experimentally. Relative to controls, the production of foliage doubled in response to high N availability, and the production of foliage, stems, coarse roots, and fine roots was halved in response to N deprivation. The period of foliage production was lengthened by fertilization and the period of fine root production was shortened by N deprivation compared with controls. In August, a shift in priority C allocation from foliage to roots occurred in the N-deprivation treatment. Therefore, during this month alone, the shoot to root ratio was greater in fertilized plants (1.0) than in N-deprived plants (0.5). Allocation to storage reserves was highest in N-deprived and lowest in fertilized plants (average 160 vs. 125 mg glucose/g biomass produced), and storage in roots of unfertilized plants commenced earlier (August) than in fertilized plants (after September). This resulted in unfertilized plants having higher fine root starch concentrations (5.2%) than fertilized plants (4.0%) in December, although sugar concentrations were similar (5.7%). The lengthened season of shoot growth and the low starch to sugar ratios in fine roots of fertilized plants are symptoms consistent with a higher risk of frost injury and microbial pathogen infection. Although soil N availability did not influence the sulfate-S content in foliage, N deprivation resulted in higher organic S to N ratios. This suggests that more S-containing proteins are produced when N availability is poor.

scholarly journals Morphological and Physiological Root Traits and Their Relationship with Nitrogen Uptake in Wheat Varieties Released from 1915 to 2013

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1149
Author(s):  
Guglielmo Puccio ◽  
Rosolino Ingraffia ◽  
Dario Giambalvo ◽  
Gaetano Amato ◽  
Alfonso S. Frenda
Keyword(s):  
Durum Wheat ◽  
Root System ◽  
N Uptake ◽  
Specific Root Length ◽  
Root Traits ◽  
Wheat Breeding ◽  
N Availability ◽  
Wheat Varieties ◽  
Uptake Efficiency ◽  
Positive Effects

Identifying genotypes with a greater ability to absorb nitrogen (N) may be important to reducing N loss in the environment and improving the sustainability of agricultural systems. This study extends the knowledge of variability among wheat genotypes in terms of morphological or physiological root traits, N uptake under conditions of low soil N availability, and in the amount and rapidity of the use of N supplied with fertilizer. Nine genotypes of durum wheat were chosen for their different morpho-phenological characteristics and year of their release. The isotopic tracer 15N was used to measure the fertilizer N uptake efficiency. The results show that durum wheat breeding did not have univocal effects on the characteristics of the root system (weight, length, specific root length, etc.) or N uptake capacity. The differences in N uptake among the studied genotypes when grown in conditions of low N availability appear to be related more to differences in uptake efficiency per unit of weight and length of the root system than to differences in the morphological root traits. The differences among the genotypes in the speed and the ability to take advantage of the greater N availability, determined by N fertilization, appear to a certain extent to be related to the development of the root system and the photosynthesizing area. This study highlights some variability within the species in terms of the development, distribution, and efficiency of the root system, which suggests that there may be sufficient grounds for improving these traits with positive effects in terms of adaptability to difficult environments and resilience to climate change.

Impact of tillage and landscape position on nitrogen availability and yield of spring wheat in the Brown soil zone in southwestern Saskatchewan

1998 ◽  
Vol 78 (3) ◽  
pp. 563-572 ◽  
Author(s):  
V. Jowkin ◽  
J. J. Schoenau
Keyword(s):  
Spring Wheat ◽  
Nitrogen Availability ◽  
N Uptake ◽  
Wheat Crop ◽  
N Availability ◽  
Inorganic N ◽  
Brown Soil ◽  
Soil Zone ◽  
No Till ◽  
Crop N Uptake

Nitrogen availability to a spring wheat crop was examined in the cropping season in a side-by-side comparison of no-till (first year) and tillage fallow in an undulating farm field in the Brown soil zone in southwestern Saskatchewan. Thirty different sampling points along a grid in each tillage landscape were randomly selected, representing 10 each of shoulder, footslope and level landscape positions. Nitrogen availability was studied i) by profile inorganic N content ii) by crop N uptake and yield of spring wheat (Triticum aestivum L.) and iii) by 15N tracer technique and in situ burial of anion exchange resin membranes (AEM).Pre-seeding available moisture content of the surface soil samples was significantly higher under no-till compared with tillage fallow. However, no significant differences in pre-seeding profile total inorganic N, crop N uptake and yield were observed between the treatments. At the landform scale, shoulder positions of the respective tillage systems had lower profile inorganic N, crop N uptake and yield compared with other slope positions. Soil N supply power, as determined by 15N tracer and AEM techniques, was not significantly different between the tillage treatments, indicating that N availability is not likely to be greatly affected in initial years by switching to no-till fallow in these soils under normal moisture conditions. Key words: Summerfallow, landscape, nitrogen, wheat

scholarly journals The Mycorrhizal Tragedy of the Commons

2021 ◽  
Author(s):  
Nils Henriksson ◽  
Oskar Franklin ◽  
Lasse Tarvainen ◽  
John Marshall ◽  
Judith Lundberg-Felten ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Boreal Forests ◽  
Nitrogen Availability ◽  
Carbon Allocation ◽  
Tragedy Of The Commons ◽  
Nitrogen Immobilization ◽  
Mycorrhizal Symbiosis ◽  
Individual Tree ◽  
Carbon Supply ◽  
The Commons

The mycorrhizal symbiosis is ubiquitous in boreal forests. Trees and plants provide their fungal partners with photosynthetic carbon in exchange for soil nutrients like nitrogen, which is critical to the growth and survival of the plants. But plant carbon allocation to mycorrhizal symbionts can also fuel nitrogen immobilization, hampering tree growth. Here we present results from field and greenhouse experiments combined with mathematical modelling, showing that mycorrhizal fungi can be simultaneously mutualistic to an individual tree and parasitic to the networked community of trees. Mycorrhizal networks connect multiple plants and fungi, and we show that each tree gains additional nitrogen at the expense of its neighbors by supplying more carbon to the fungi. But this additional carbon supply eventually aggravates nitrogen immobilization in the shared fungal biomass. Individual trees may thus independently benefit from increasing their carbon investment to mycorrhiza, while causing a decline in nitrogen availability for the whole plant community. We illustrate the evolutionary underpinnings of this situation by drawing on the analogous the tragedy of the commons, and explain how rising atmospheric CO2 may lead to greater nitrogen immobilization in the future.

Liming improves soil microbial growth, but trash blanket placement increases labile carbon and nitrogen availability in a sugarcane soil of subtropical Australia

Soil Research ◽  
2018 ◽  
Vol 56 (3) ◽  
pp. 235 ◽  
Author(s):  
X. Y. Liu ◽  
M. Rezaei Rashti ◽  
M. Esfandbod ◽  
B. Powell ◽  
C. R. Chen
Keyword(s):  
Soil Ph ◽  
Enzyme Activities ◽  
Nitrogen Availability ◽  
Microbial Community Composition ◽  
Cropping System ◽  
Hot Water ◽  
Microbial Biomass C ◽  
N Availability ◽  
Total N ◽  
Soil Microbial

Liming has been widely used to decrease soil acidity, but its effects on soil nitrogen (N) availability and microbial processes in sugarcane fields are largely unknown. Adjacent sugarcane soils at 26 months after liming (26ML), 14 months after liming (14ML) and with no lime amendment (CK) in Bundaberg, Australia, were selected to investigate the effect of liming on soil N bioavailability and microbial activity in a long-term subtropical sugarcane cropping system. Liming in both 14ML and 26ML treatments significantly increased soil pH (by 1.2–1.4 units) and exchangeable Ca2+ (>2-fold) compared with the CK treatment. The lower concentrations of hot water extractable organic carbon (C) and total N and ammonium-N in the 14ML, compared with the CK and 26ML treatments, can be attributed to the absence of trash blanket placement in the former. Enhanced microbial immobilisation due to improved soil pH by liming (14ML and 26ML treatments) led to increased soil microbial biomass C and N, particularly in the presence of a trash blanket (26 ML treatment), but decreased soil respiration and metabolic quotient indicated that acidic stress conditions were alleviated in the liming treatments. Soil pH was the main factor governing soil enzyme activities, with an overall decrease in all enzyme activities in response to liming. Overall, liming and trash blanket practices improved sugarcane soil fertility. Further study is warranted to investigate the shifts in soil microbial community composition and the diversity and abundance of N-associated functional genes in response to liming in sugarcane fields.

Responses of two hybrid Populus clones to flooding, drought, and nitrogen availability. I. Morphology and growth

1992 ◽  
Vol 70 (11) ◽  
pp. 2265-2270 ◽  
Author(s):  
Zhijun Liu ◽  
Donald I. Dickmann
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Nitrogen Availability ◽  
Carbon Allocation ◽  
Hybrid Poplar ◽  
Leaf Expansion ◽  
Root Production ◽  
Leaf Initiation ◽  
Stem Biomass ◽  
Nitrogen Levels

Repeated progressive drought and flooding stress were imposed on hybrid poplar clones Populus × euramericana 'Eugenei', and Populus tristis × Populus balsamifera ‘Tristis’ grown in pots in a greenhouse under two nitrogen levels. In both clones the rate of leaf initiation was promoted only in high-N plants subjected to minimum water stress. Water stress alone did not retard the rate of leaf initiation, but it significantly reduced leaf expansion of 'Eugenei', whereas only flooding led to smaller leaves in 'Tristis'. The addition of N stimulated leaf expansion, leaf chlorophyll and N concentrations, and leaf and stem biomass production across soil moisture levels, but the greatest effect of N was associated with minimum water stress. High N altered carbon allocation towards the aboveground portions, leading to lower root to shoot ratios. High N also appeared to stimulate initiation of fine roots. Soil moisture determined the amount of biomass that accumulated in roots, with highest root production in well-watered pots and lowest in flooded pots, with the droughted treatment in between. Leaves became thinner as soil moisture decreased from flooding. Stem biomass of 'Tristis' declined more under flooding than under drought, whereas 'Eugenei' displayed a greater reduction of stem biomass in droughty than in flooded soil. Key words: water stress, nitrogen, leaf and root morphology, root to shoot ratio, biomass, Populus, flooding.

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