Responses of fine root exudation, respiration, and morphology in three early successional tree species to increased air humidity and different soil nitrogen sources

2021 ◽  
Author(s):  
Marili Sell ◽  
Ivika Ostonen ◽  
Gristin Rohula-Okunev ◽  
Linda Rusalepp ◽  
Azadeh Rezapour ◽  
...  
Keyword(s):  
Soil Nitrogen ◽  
Root Morphology ◽  
Fine Roots ◽  
Root Respiration ◽  
Fine Root ◽  
Water Flux ◽  
Nitrogen Sources ◽  
Air Humidity ◽  
Fine Root Morphology ◽  
Species Specific

Abstract Global climate change scenarios predict an increase in air temperature, precipitation, and air humidity for northern latitudes. Elevated air humidity may significantly reduce the water flux through forest canopies and affect interactions between water and nutrient uptake. However, we have limited understanding of how altered transpiration would affect root respiration and carbon (C) exudation as fine root morphology acclimates to different water flux. We investigated the effects of elevated air relative humidity (eRH) and different inorganic nitrogen sources (NO3− and NH4+) on above and belowground traits in hybrid aspen (Populus × wettsteinii Hämet-Ahti), silver birch (Betula pendula Roth.), and Scots pine (Pinus sylvestris L.) grown under controlled climate chamber conditions. The eRH significantly decreased the transpiration flux in all species, decreased root mass-specific exudation in pine, and increased root respiration in aspen. eRH also affected fine root morphology, with specific root area increasing for birch but decreasing in pine. The species comparison revealed that pine had the highest C exudation, while birch had the highest root respiration rate. Both humidity and nitrogen treatments affected the share of absorptive and pioneer roots within fine roots; however, the response was species-specific. The proportion of absorptive roots was highest in birch and aspen, the share of pioneer roots was greatest in aspen, and the share of transport roots was greatest in pine. Fine roots with lower root tissue density were associated with pioneer root tips and had a higher C exudation rate. Our findings underline the importance of considering species-specific differences in relation to air humidity and soil nitrogen availability that interactively affect the C input–output balance. We highlight the role of changes in the fine root functional distribution as an important acclimation mechanism of trees in response to environmental change.

Carbon allocation in early successional tree species at elevated air humidity and different soil nitrogen sources

2021 ◽  
Author(s):  
Marili Sell ◽  
Ivika Ostonen ◽  
Gristin Rohula-Okunev ◽  
Azadeh Rezapour ◽  
Priit Kupper
Keyword(s):  
Biomass Allocation ◽  
Tree Species ◽  
Root Respiration ◽  
Fine Root ◽  
Silver Birch ◽  
Organic Carbon Content ◽  
Climate Change Scenarios ◽  
Air Humidity ◽  
Species Specific ◽  
Exudation Rate

<p>Global climate change scenarios predict increasing air temperature, enhanced precipitation and air humidity for Northern latitudes. We investigated the effects of elevated air relative humidity (RH) and different inorganic nitrogen sources (NO<sub>3</sub><sup>-</sup>, NH<sub>4</sub><sup>+</sup>) on above- and belowground traits in different tree species, with particular emphasis on rhizodeposition rates. Silver birch, hybrid aspen and Scots pine saplings were grown in PERCIVAL growth chambers with stabile temperature, light intensity and two different air humidity conditions: moderate (mRH, 65% at day and 80% at night) and elevated (eRH, 80% at day and night). The collection of fine root exudates was conducted by a culture-based cuvette method and total organic carbon content was determined by Vario TOC analyser. Fine root respiration was measured with an infra-red gas analyser CIRAS 2.  </p><p>We analysed species-specific biomass allocation, water and rhizodeposition fluxes, foliar and fine root traits in response to changing environmental conditions. The eRH significantly decreased the transpiration flux in all species. In birch the transpiration flux was also affected by the nitrogen source. The average carbon exudation rate for aspen, birch and pine varied from 2 to 3  μg C g<sup>-1</sup> day <sup>-1</sup>. The exudation rates for deciduous tree species tended to increase at eRH, while conversely decreased for coniferous trees (p=0.045), coinciding with the changes in biomass allocation. C flux released by fine root respiration varied more than the fine root exudation, whereas the highest root respiration was found in silver birch and lowest in aspen. At eRH the above and belowground biomass ratio in aspen increased, at the expense of decreased root biomass and root respiration.  </p><p>Moreover, eRH significantly affected fine root morphology, whereas the response of specific root area was reverse for deciduous and coniferous tree species. However, fine roots with lower root tissue density had higher C exudation rate. Our findings underline the importance of considering species-specific differences by elucidating tree’s acclimation to environmental factors and their interactions.   </p>

Effects of precipitation change on fine root morphology and dynamics at a global scale: a meta-analysis

2019 ◽  
Vol 99 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Xin Zhang ◽  
Yajuan Xing ◽  
Guoyong Yan ◽  
Shijie Han ◽  
Qinggui Wang
Keyword(s):  
Root Morphology ◽  
Fine Roots ◽  
Fine Root ◽  
Meta Analysis ◽  
Root Diameter ◽  
Precipitation Change ◽  
Deep Soil ◽  
Fine Root Morphology ◽  
Precipitation Changes ◽  
Experiment Duration

We compiled data from 495 observations and 103 papers and carried out a meta-analysis of the responses of fine root biomass, production, decomposition, and morphology to precipitation increases and decreases. In addition, we evaluated the effects of plant life form, soil depth, and experiment duration on the responses of fine roots to precipitation changes. Our results confirmed that decreased precipitation limited fine root diameter and accelerated turnover. Increased precipitation stimulated fine root elongation and enhanced the fine root accumulation. The responses of fine roots to precipitation changes varied among plants of different life forms. Tree fine root production and decomposition and non-tree fine root diameter varied most strongly under decreased precipitation. Specific root length of non-tree fine roots was much higher than that of tree fine roots under increased precipitation. Decreased precipitation limited the growth of fine roots in 20–40 cm deep soil, whereas increased precipitation promoted the growth of fine roots in both shallow and deep soil layers. The responses of fine roots to decreased precipitation were affected by experiment duration. Results filled the gap of evaluation data on the effect of precipitation change on fine root morphology and dynamics, which are useful for better predicting the C cycle under precipitation change.

scholarly journals Wind intensity affects fine root morphological traits with consequences for plant-soil feedback effects

AoB Plants ◽  
2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Luise Werger ◽  
Joana Bergmann ◽  
Ewald Weber ◽  
Johannes Heinze
Keyword(s):  
Root Morphology ◽  
Morphological Traits ◽  
Fine Root ◽  
High Wind ◽  
Root:Shoot Ratio ◽  
Fine Root Morphology ◽  
Plant Soil ◽  
Induced Changes ◽  
Wind Intensity ◽  
Plant Soil Interactions

Abstract Wind influences the development, architecture and morphology of plant roots and may modify subsequent interactions between plants and soil (plant–soil feedbacks—PSFs). However, information on wind effects on fine root morphology is scarce and the extent to which wind changes plant–soil interactions remains unclear. Therefore, we investigated the effects of two wind intensity levels by manipulating surrounding vegetation height in a grassland PSF field experiment. We grew four common plant species (two grasses and two non-leguminous forbs) with soil biota either previously conditioned by these or other species and tested the effect of wind on root:shoot ratio, fine root morphological traits as well as the outcome for PSFs. Wind intensity did not affect biomass allocation (i.e. root:shoot ratio) in any species. However, fine-root morphology of all species changed under high wind intensity. High wind intensity increased specific root length and surface area and decreased root tissue density, especially in the two grasses. Similarly, the direction of PSFs changed under high wind intensity in all four species, but differences in biomass production on the different soils between high and low wind intensity were marginal and most pronounced when comparing grasses with forbs. Because soils did not differ in plant-available nor total nutrient content, the results suggest that wind-induced changes in root morphology have the potential to influence plant–soil interactions. Linking wind-induced changes in fine-root morphology to effects on PSF improves our understanding of plant–soil interactions under changing environmental conditions.

scholarly journals Fine Root Morphology, Biochemistry and Litter Quality Indices of Fast- and Slow-growing Woody Species in Ethiopian Highland Forest

Ecosystems ◽  
2017 ◽  
Vol 21 (3) ◽  
pp. 482-494 ◽  
Author(s):  
Dessie Assefa ◽  
Douglas L. Godbold ◽  
Beyene Belay ◽  
Abrham Abiyu ◽  
Boris Rewald
Keyword(s):  
Root Morphology ◽  
Litter Quality ◽  
Fine Root ◽  
Woody Species ◽  
Quality Indices ◽  
Fine Root Morphology ◽  
Ethiopian Highland ◽  
Slow Growing

Insitu needle and fine root respiration in mature slash pine (Pinuselliottii) trees

1991 ◽  
Vol 21 (11) ◽  
pp. 1589-1595 ◽  
Author(s):  
Wendell P. Cropper Jr. ◽  
Henry L. Gholz
Keyword(s):  
Time Series ◽  
Fine Roots ◽  
Root Respiration ◽  
Fine Root ◽  
Time Of Day ◽  
Slash Pine ◽  
Chamber System ◽  
North Central ◽  
Central Florida ◽  
Respiration Rates

Respiration of needles and surface fine roots was measured in a north central Florida slash pine (Pinuselliottii Engelm. var. elliottii) plantation. A controlled temperature chamber system was used to estimate respiration rates and Q10 values of insitu tissues over a range of 10 to 35 °C. Respiration rates did not differ significantly among seasons, fertilized versus unfertilized plots, or time of day in a diurnal time series (needles). Needle respiration from the lower canopy was less than that from the upper canopy. Fine root respiration measurements were consistent with previously made estimates based on soil CO2 partitioning and trenched plots.

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