Spatial–temporal variations of absorptive fine roots in the organic and soil layers of a Larix gmelinii forest

Trees ◽  
2021 ◽  
Author(s):  
Guoqiang Gao ◽  
Marc Goebel ◽  
Yan Wang ◽  
Zhengquan Wang ◽  
Jiacun Gu
Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 42
Author(s):  
Yan Wang ◽  
Zhongyue Li ◽  
Zhengquan Wang ◽  
Jiacun Gu

Absorptive and transport fine roots (diameter ≤ 2 mm) differ greatly in anatomy, morphology, and physiology, as well as their responses to environmental changes. However, it is still not well understood how their functional traits and biomass repartition respond to resource variability associated with increasing soil depth. Herein, we sampled the first five order roots of three hardwoods, i.e., Juglans mandshurica Maxim., Fraxinus mandshurica Rupr., and Phellodendron amurense Rupr. at surface (0–10 cm) and subsurface (20–30 cm) soil layers, respectively, and measured root biomass, anatomy, morphology, chemistry, and physiology at the branch-order level. Based on the anatomical characteristics, absorptive and transport fine roots were identified within each order, and their amounts and functional trait plasticity to soil depth were examined. The results showed that across soil layers, the first three order roots were mainly absorptive roots, while the fourth- and fifth-order roots were transport ones. From surface to subsurface soil layers, both the number and biomass proportion of absorptive fine roots decreased but those of transport fine roots increased. Transport fine root traits were more plastic to soil depth than absorptive ones, especially for the conduit-related traits. Absorptive fine roots in surface soil generally had stronger potential for resource acquisition than those in deeper soil, as indicated by their longer specific root length and greater root branching density. In comparison, transport fine roots in deeper soil were generally enhanced in their transportation function, with wider stele and higher hydraulic conductivity. Our findings suggest that functional specialization via multi-trait plasticity and coordination in both absorptive and transport fine roots along the soil depth would benefit the efficient soil resource exploitation of trees in forest ecosystems.


2018 ◽  
Vol 15 (7) ◽  
pp. 2231-2249 ◽  
Author(s):  
Marie-Pierre Turpault ◽  
Christophe Calvaruso ◽  
Gil Kirchen ◽  
Paul-Olivier Redon ◽  
Carine Cochet

Abstract. The role of forest vegetation in the silicon (Si) cycle has been widely examined. However, to date, little is known about the specific role of fine roots. The main objective of our study was to assess the influence of fine roots on the Si cycle in a temperate forest in north-eastern France. Silicon pools and fluxes in vegetal solid and solution phases were quantified within each ecosystem compartment, i.e. in the atmosphere, above-ground and below-ground tree tissues, forest floor and different soil layers, on three plots, each with different soil types, i.e. Dystric Cambisol (DC), Eutric Cambisol (EC) and Rendzic Leptosol (RL). In this study, we took advantage of a natural soil gradient, from shallow calcic soil to deep moderately acidic soil, with similar climates, atmospheric depositions, species compositions and management. Soil solutions were measured monthly for 4 years to study the seasonal dynamics of Si fluxes. A budget of dissolved Si (DSi) was also determined for the forest floor and soil layers. Our study highlighted the major role of fine roots in the Si cycle in forest ecosystems for all soil types. Due to the abundance of fine roots mainly in the superficial soil layers, their high Si concentration (equivalent to that of leaves and 2 orders higher than that of coarse roots) and their rapid turnover rate (approximately 1 year), the mean annual Si fluxes in fine roots in the three plots were 68 and 110 kgha-1yr-1 for the RL and the DC, respectively. The turnover rates of fine roots and leaves were approximately 71 and 28 % of the total Si taken up by trees each year, demonstrating the importance of biological recycling in the Si cycle in forests. Less than 1 % of the Si taken up by trees each year accumulated in the perennial tissues. This study also demonstrated the influence of soil type on the concentration of Si in the annual tissues and therefore on the Si fluxes in forests. The concentrations of Si in leaves and fine roots were approximately 1.5–2.0 times higher in the Si-rich DC compared to the Si-poor RL. In terms of the DSi budget, DSi production was large in the three plots in the forest floor (9.9 to 12.7 kgha-1yr-1), as well as in the superficial soil layer (5.3 to 14.5 kgha-1yr-1), and decreased with soil depth. An immobilization of DSi was even observed at 90 cm depth in plot DC (−1.7 kgha-1yr-1). The amount of Si leached from the soil profile was relatively low compared to the annual uptake by trees (13 % in plot DC to 29 % in plot RL). The monthly measurements demonstrated that the seasonal dynamics of the DSi budget were mainly linked to biological activity. Notably, the peak of dissolved Si production in the superficial soil layer occurred during winter and probably resulted from fine-root decomposition. Our study reveals that biological processes, particularly those involving fine roots, play a predominant role in the Si cycle in temperate forest ecosystems, while the geochemical processes appear to be limited.


Plant Root ◽  
2021 ◽  
Vol 15 (0) ◽  
pp. 60-68
Author(s):  
Keina Motegi ◽  
Yoshihiro Kobae ◽  
Emi Kameoka ◽  
Mikoto Kaneko ◽  
Tomoko Hatanaka ◽  
...  

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8194 ◽  
Author(s):  
Lu Gong ◽  
Jingjing Zhao

Fine roots are essential for water and nutrient uptake in plants, but little is known about the variation in fine root traits and the underlying mechanisms that drive it. Understanding the responses of fine root function traits to changing environmental conditions and the role of fine root traits as drivers of forest ecosystem processes are critical for informing physiological and ecological theory as well as ecosystem management. We measured morphological and physiological traits of fine roots from six soil layers and three diameter classes in Schrenk’s spruce (Picea shrenkiana) forests of the Tianshan mountains, China. We found significant effects of nitrogen addition on these morphological and physiological traits, which varied by soil layer and root diameter. Specifically, specific root length (SRL) was higher in medium N addition group (N2) than in control group (N0). Specific root area (SRA) was higher in the control group (N0) than fertilized groups (N1, N2 and N3). Root tissue density (RTD) was higher in low N addition group (N1) than in the other group. Root dry matter content had no significant difference among four treatment groups. SRL, SRA, and RTD of fine roots in different diameter classes were all significantly different between high N addition (N3) and the control (N0) groups. The physiological characteristics of fine roots showed that soluble sugar (SS), fine root vitality (FRV), and tissue water content (TWC) in different soil layers were higher in the control group than in the fertilized groups. While soluble protein (SP), malondialdehyde (MDA) and free proline (FP) were lower in the control group (N0) than in the fertilized groups. In addition, SS, FRV, SP, TWC, FP, and MDA in all N addition treatments groups were significantly different from the control group. Fine root morphological traits were closely related to physiological traits, and added nitrogen inputs change these correlations. Our study confirms that nitrogen addition has specific effects on the morphological and physiological traits of fine roots of Schrenk’s spruce, and the effects of N addition vary according to the amount added.


2019 ◽  
Vol 431 ◽  
pp. 6-16 ◽  
Author(s):  
B. Bordron ◽  
A. Robin ◽  
I.R. Oliveira ◽  
J. Guillemot ◽  
J.P. Laclau ◽  
...  

2018 ◽  
pp. 57-62 ◽  
Author(s):  
N. Conceição ◽  
L. Tezza ◽  
S. Lourenço ◽  
M. Häusler ◽  
L. Boteta ◽  
...  
Keyword(s):  

2016 ◽  
Vol 58 (4) ◽  
pp. 220-227 ◽  
Author(s):  
Dorota Grygoruk

Abstract Fine root biomass of forest trees is a recognised indicator of environmental changes in the conditions of global climate change. The present study was carried out in six old-growth beech forests (112-140 years) located in different climatic conditions on the range border of Fagus sylvatica L. in Poland. The root biomass was investigated by soil coring method in the upper soil layers (0-5 cm, 5-15 cm and total layer 0-15 cm). The significantly greater total root biomass was found in the beech stands, which characterised by higher average precipitation and lower average annual temperatures in the period 2000-2005. The share of roots of diameter > 5 mm increased with increasing depth of top soils. Biomass of fine roots (diameter ≤ 2 mm) decreased with increasing depth of upper soil layers. The average biomass of fine roots ranged from 175.36 to 418.16 g m-2 in the soil layer 0-15 cm. The significant differences of fine root biomass were found between studied stands in the soil layers 0-5 cm and 0-15 cm. Also, it was found significant positive correlation between fine root biomass in the soil layer 0-15 cm and precipitation during the growing season in 2006. Precipitation in the study period was connected with very high rainfall in August 2006, repeatedly exceeding the long-term monthly levels. Regional climatic conditions, in that extreme weather events in growing seasons can significantly to affect changes of fine root biomass of forest trees, consequently, changes of relationships between the growth of above- and below-ground of the old-growth forest stands.


2017 ◽  
Vol 421 (1-2) ◽  
pp. 301-318 ◽  
Author(s):  
George Rodrigues Lambais ◽  
Christophe Jourdan ◽  
Marisa de Cássia Piccolo ◽  
Amandine Germon ◽  
Rafael Costa Pinheiro ◽  
...  

2021 ◽  
Vol 9 (2) ◽  
pp. 323
Author(s):  
Huan Pablo De Souza ◽  
Dione Richer Momolli ◽  
Mauro Valdir Schumacher ◽  
Aline Aparecida Ludvichak ◽  
Angélica Costa Malheiros ◽  
...  

The fine root component, although it represents the lowest proportional biomass in a tree, has an important function in obtaining water and nutrients. In addition, it is an indicator of the physiological quality and growth of a tree. Thus, the objective of the study was to evaluate the spatial distribution of biomass and the density of fine roots in five different fertilizer treatments. The five treatments received increasing amounts of fertilizers. The collections were made between trees in the planting line and between the planting lines. Soil layers of 25 cm x 25 cm x 20 cm (length x width x depth) were collected until reaching a depth of 1 meter. Treatments that had less nutrient input via fertilization showed higher production of fine roots. In general, the line position in the superficial layers showed a higher density of fine roots. There was significant difference between the positions of the land monoliths and between the different layers. Strategically, the lower supply of nutrients via fertilization provided greater investment in the production of fine roots by trees in order to increase the area of absorption and exploration of the soil.


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