Intraspecific variation in fine root respiration and morphology in response to in situ soil nitrogen fertility in a 100-year-old Chamaecyparis obtusa forest

Oecologia ◽  
2015 ◽  
Vol 179 (4) ◽  
pp. 959-967 ◽  
Author(s):  
Naoki Makita ◽  
Yasuhiro Hirano ◽  
Takanobu Sugimoto ◽  
Toko Tanikawa ◽  
Hiroaki Ishii
2021 ◽  
Author(s):  
Marili Sell ◽  
Ivika Ostonen ◽  
Gristin Rohula-Okunev ◽  
Linda Rusalepp ◽  
Azadeh Rezapour ◽  
...  

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.


2015 ◽  
Vol 21 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Zongrui Lai ◽  
Su Lu ◽  
Yuqing Zhang ◽  
Bin Wu ◽  
Shugao Qin ◽  
...  

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Juan Piñeiro ◽  
Raúl Ochoa-Hueso ◽  
Manuel Delgado-Baquerizo ◽  
Silvan Dobrick ◽  
Peter B. Reich ◽  
...  

Trees ◽  
2015 ◽  
Vol 30 (2) ◽  
pp. 415-429 ◽  
Author(s):  
Kouhei Miyatani ◽  
Yuki Mizusawa ◽  
Kazuki Okada ◽  
Toko Tanikawa ◽  
Naoki Makita ◽  
...  

2021 ◽  
Author(s):  
Marili Sell ◽  
Ivika Ostonen ◽  
Gristin Rohula-Okunev ◽  
Azadeh Rezapour ◽  
Priit Kupper

<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>


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