scholarly journals Effects of drought on nitrogen uptake and carbon dynamics in trees

2020 ◽  
Author(s):  
Jobin Joseph ◽  
Jörg Luster ◽  
Alessandra Bottero ◽  
Nathalie Buser ◽  
Lukas Baechli ◽  
...  

Abstract Research on drought impact on tree functioning is focused primarily on water and carbon (C) dynamics. Changes in nutrient uptake might also affect tree performance under drought and there is a need to explore underlying mechanisms. We investigated effects of drought on a) in-situ nitrogen (N)-uptake accounting for both, N availability to fine-roots in soil and actual N-uptake, b) physiological N-uptake capacity of roots, and c) the availability of new assimilates to fine roots influencing the N-uptake capacity using 15N and 13C labelling. We assessed saplings of six different tree species (Acer peudoplatanus, Fagus sylvatica, Quercus petraea, Abies alba, Picea abies, Pinus sylvestris). Drought resulted in significant reduction of in-situ soil N-uptake in deciduous trees accompanied by reduced carbon allocation to roots and by a reduction in root biomass available for N-uptake. While physiological root N-uptake capacity was not affected by drought in deciduous saplings, reduced maximum ammonium but not nitrate uptake was observed for A.alba and P.abies. Our results indicate that drought has species-specific effects on N-uptake. Even water limitations of only 5 weeks as assessed here can decrease whole plant inorganic N-uptake independent of whether the physiological N-uptake capacity is affected or not.

Author(s):  
Olivia H. Cousins ◽  
Trevor P. Garnett ◽  
Amanda Rasmussen ◽  
Sacha J. Mooney ◽  
Ronald J. Smernik ◽  
...  

AbstractDue to climate change, water availability will become increasingly variable, affecting nitrogen (N) availability. Therefore, we hypothesised watering frequency would have a greater impact on plant growth than quantity, affecting N availability, uptake and carbon allocation. We used a gravimetric platform, which measures the unit of volume per unit of time, to control soil moisture and precisely compare the impact of quantity and frequency of water under variable N levels. Two wheat genotypes (Kukri and Gladius) were used in a factorial glasshouse pot experiment, each with three N application rates (25, 75 and 150 mg N kg−1 soil) and five soil moisture regimes (changing water frequency or quantity). Previously documented drought tolerance, but high N use efficiency, of Gladius as compared to Kukri provides for potentially different responses to N and soil moisture content. Water use, biomass and soil N were measured. Both cultivars showed potential to adapt to variable watering, producing higher specific root lengths under low N coupled with reduced water and reduced watering frequency (48 h watering intervals), or wet/dry cycling. This affected mineral N uptake, with less soil N remaining under constant watering × high moisture, or 48 h watering intervals × high moisture. Soil N availability affected carbon allocation, demonstrated by both cultivars producing longer, deeper roots under low N. Reduced watering frequency decreased biomass more than reduced quantity for both cultivars. Less frequent watering had a more negative effect on plant growth compared to decreasing the quantity of water. Water variability resulted in differences in C allocation, with changes to root thickness even when root biomass remained the same across N treatments. The preferences identified in wheat for water consistency highlights an undeveloped opportunity for identifying root and shoot traits that may improve plant adaptability to moderate to extreme resource limitation, whilst potentially encouraging less water and nitrogen use.


2004 ◽  
Vol 34 (3) ◽  
pp. 754-761 ◽  
Author(s):  
Ryan D Hangs ◽  
Ken J Greer ◽  
Catharine A Sulewski

During the early establishment phase, outplanted white spruce (Picea glauca (Moench) Voss) and jack pine (Pinus banksiana Lamb.) seedlings are vulnerable to lethargic growth or mortality because of interspecific competition for soil nutrients, particularly N. Accurately quantifying the degree of N competition is essential for supporting effective vegetation management (VM) decisions. This study evaluated the use of in situ burials of ion-exchange membrane (IEM; Plant Root SimulatorTM-probes) for quantifying differences in soil N supply rate between different VM treatments and the relationship of this N availability index to early growth of conifer seedlings at four boreal forest sites. At most sites, the effect of noncrop N uptake on soil N availability was apparent, with smaller NH4+-N, NO3–-N, and total dissolved inorganic N (DIN) supply rates in control plots than in VM plots. Total DIN supply rate was correlated (R2 = 0.60 to 0.73, P < 0.01) with seedling height, root-collar diameter, and stem volume growth. Ammonium-N supply rate was better correlated than NO3–-N supply rate with conifer seedling growth, which is in agreement with preferential NH4+-N uptake by conifer species. The results of this study support the use of in situ burials of IEM for measuring soil N availability during the early establishment phase.


2019 ◽  
Author(s):  
Thibaut Fréjaville ◽  
Bruno Fady ◽  
Antoine Kremer ◽  
Alexis Ducousso ◽  
Marta Benito Garzón

ABSTRACTAimTo test whether adaptive and plastic trait responses to climate across species distribution ranges can be untangled using field observations, under the rationale that, in natural forest tree populations, long-term climate shapes local adaptation while recent climate change drives phenotypic plasticity.LocationEurope.Time period1901-2014.TaxaSilver fir (Abies alba Mill.) and sessile oak (Quercus petraea (Matt.) Liebl.).MethodsWe estimated the variation of individual tree height as a function of long-term and short-term climates to tease apart local adaptation, plasticity and their interaction, using mixed-effect models calibrated with National Forest Inventory data (in-situ models). To validate our approach, we tested the ability of in-situ models to predict independently tree height observations in common gardens where local adaptation to climate of populations and their plasticity can be measured and separated. In-situ model predictions of tree height variation among provenances (populations of different geographical origin) and among planting sites were compared to observations in common gardens and to predictions from a similar model calibrated using common garden data (ex-situ model).ResultsIn Q. petraea, we found high correlations between in-situ and ex-situ model predictions of provenance and plasticity effects and their interaction on tree height (r > 0.80). We showed that the in-situ models significantly predicted tree height variation among provenances and sites for Abies alba and Quercus petraea. Spatial predictions of phenotypic plasticity across species distribution ranges indicate decreasing tree height in populations of warmer climates in response to recent anthropogenic climate warming.Main conclusionsOur modelling approach using National Forest Inventory observations provides a new perspective for understanding patterns of intraspecific trait variation across species ranges. Its application is particularly interesting for species for which common garden experiments do not exist or do not cover the entire climatic range of the species.


1992 ◽  
Vol 22 (4) ◽  
pp. 447-456 ◽  
Author(s):  
Marianne K. Burke ◽  
Dudley J. Raynal ◽  
Myron J. Mitchell

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.


2021 ◽  
Vol 13 (10) ◽  
pp. 5649
Author(s):  
Giovani Preza-Fontes ◽  
Junming Wang ◽  
Muhammad Umar ◽  
Meilan Qi ◽  
Kamaljit Banger ◽  
...  

Freshwater nitrogen (N) pollution is a significant sustainability concern in agriculture. In the U.S. Midwest, large precipitation events during winter and spring are a major driver of N losses. Uncertainty about the fate of applied N early in the growing season can prompt farmers to make additional N applications, increasing the risk of environmental N losses. New tools are needed to provide real-time estimates of soil inorganic N status for corn (Zea mays L.) production, especially considering projected increases in precipitation and N losses due to climate change. In this study, we describe the initial stages of developing an online tool for tracking soil N, which included, (i) implementing a network of field trials to monitor changes in soil N concentration during the winter and early growing season, (ii) calibrating and validating a process-based model for soil and crop N cycling, and (iii) developing a user-friendly and publicly available online decision support tool that could potentially assist N fertilizer management. The online tool can estimate real-time soil N availability by simulating corn growth, crop N uptake, soil organic matter mineralization, and N losses from assimilated soil data (from USDA gSSURGO soil database), hourly weather data (from National Weather Service Real-Time Mesoscale Analysis), and user-entered crop management information that is readily available for farmers. The assimilated data have a resolution of 2.5 km. Given limitations in prediction accuracy, however, we acknowledge that further work is needed to improve model performance, which is also critical for enabling adoption by potential users, such as agricultural producers, fertilizer industry, and researchers. We discuss the strengths and limitations of attempting to provide rapid and cost-effective estimates of soil N availability to support in-season N management decisions, specifically related to the need for supplemental N application. If barriers to adoption are overcome to facilitate broader use by farmers, such tools could balance the need for ensuring sufficient soil N supply while decreasing the risk of N losses, and helping increase N use efficiency, reduce pollution, and increase profits.


Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1149
Author(s):  
Guglielmo Puccio ◽  
Rosolino Ingraffia ◽  
Dario Giambalvo ◽  
Gaetano Amato ◽  
Alfonso S. Frenda

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.


Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 595
Author(s):  
Shama Naz ◽  
Qiufang Shen ◽  
Jonas Lwalaba Wa Lwalaba ◽  
Guoping Zhang

Nitrogen (N) availability and form have a dramatic effect on N uptake and assimilation in plants, affecting growth and development. In the previous studies, we found great differences in low-N tolerance between Tibetan wild barley accessions and cultivated barley varieties. We hypothesized that there are different responses to N forms between the two kinds of barleys. Accordingly, this study was carried out to determine the response of four barley genotypes (two wild, XZ16 and XZ179; and two cultivated, ZD9 andHua30) under 4Nforms (NO3−, NH4+, urea and glycine). The results showed significant reduction in growth parameters such as root/shoot length and biomass, as well as photosynthesis parameters and total soluble protein content under glycine treatment relative to other N treatments, for both wild and cultivated barley, however, XZ179 was least affected. Similarly, ammonium adversely affected growth parameters in both wild and cultivated barleys, with XZ179 being severely affected. On the other hand, both wild and cultivated genotypes showed higher biomass, net photosynthetic rate, chlorophyll and protein in NO3− treatment relative to other three N treatments. It may be concluded that barley undisputedly grows well under inorganic nitrogen (NO3−), however in response to the organic N wild barley prefer glycine more than cultivated barely.


Genome ◽  
2010 ◽  
Vol 53 (10) ◽  
pp. 769-777 ◽  
Author(s):  
Melanie Mehes-Smith ◽  
Paul Michael ◽  
Kabwe Nkongolo

Genome organization in the family Pinaceae is complex and largely unknown. The main purpose of the present study was to develop and physically map species-diagnostic and species-specific molecular markers in pine and spruce. Five RAPD (random amplified polymorphic DNA) and one ISSR (inter-simple sequence repeat) species-diagnostic or species-specific markers for Picea mariana , Picea rubens , Pinus strobus , or Pinus monticola were identified, cloned, and sequenced. In situ hybridization of these sequences to spruce and pine chromosomes showed the sequences to be present in high copy number and evenly distributed throughout the genome. The analysis of centromeric and telomeric regions revealed the absence of significant clustering of species-diagnostic and species-specific sequences in all the chromosomes of the four species studied. Both RAPD and ISSR markers showed similar patterns.


2013 ◽  
Vol 72 (1) ◽  
pp. 1-133 ◽  
Author(s):  
Višnja Besendorfer ◽  
Jelena Mlinarec

Abstract Satellite DNAis a genomic component present in virtually all eukaryotic organisms. The turnover of highly repetitive satellite DNAis an important element in genome organization and evolution in plants. Here we study the presence, physical distribution and abundance of the satellite DNAfamily AhTR1 in Anemone. Twenty-two Anemone accessions were analyzed by PCR to assess the presence of AhTR1, while fluorescence in situ hybridization and Southern hybridization were used to determine the abundance and genomic distribution of AhTR1. The AhTR1 repeat unit was PCR-amplified only in eight phylogenetically related European Anemone taxa of the Anemone section. FISH signal with AhTR1 probe was visible only in A. hortensis and A. pavonina, showing localization of AhTR1 in the regions of interstitial heterochromatin in both species. The absence of a FISH signal in the six other taxa as well as weak signal after Southern hybridization suggest that in these species AhTR1 family appears as relict sequences. Thus, the data presented here support the »library hypothesis« for AhTR1 satellite evolution in Anemone. Similar species-specific satellite DNAprofiles in A. hortensis and A. pavonina support the treatment of A. hortensis and A. pavonina as one species, i.e. A. hortensis s.l.


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