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F and p values of ANCOVA (General Linear Model) for the effects of core position and orientation on morphological fine root traits divided by diameter classes. Gap sizes were used as covariates. Interactions were not significant and therefore excluded from the model.
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Research Highlights: Fine roots play an important role in plant growth as well as in carbon (C) and nutrient cycling in terrestrial ecosystems. Gaining a wider knowledge of their dynamics under forest gap opening would improve our understanding of soil carbon input and below-ground carbon stock accumulation. Single-tree selection is increasingly re...
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Context 1
... total, 15 elliptical different-sized gaps ranging from 86.05 to 350.7 m 2 were selected for this study. Detailed information on gap and related tree sizes are reported in Table S1. Each single gap was considered as the experimental unit, making this experimental design a point comparison approach rather than a replicated experiment on the ecosystem scale. ...Context 2
... the edge trees, the different size of gaps did not affect the investigated morphological traits, neither the core position nor the tree orientation (Table 1). If pooled, the mean values of all morphological traits did not differ from those of the uncut control (closed canopy), independently from the size of gaps ( Figure 2); some deviations either above or below the control mean occurred in the center-left of the distribution, i.e., for the smaller gap sizes. ...Context 3
... pooled, the mean values of all morphological traits did not differ from those of the uncut control (closed canopy), independently from the size of gaps ( Figure 2); some deviations either above or below the control mean occurred in the center-left of the distribution, i.e., for the smaller gap sizes. The only exception was the slightly higher SRL for the larger fine root fraction (1-2 mm) in the side facing the gap area (Figure 3), which marginally missed the significance (core position p = 0.071; Table 1). Figure 2. Fine root length, dry mass, root tissue density (RTD), and specific root length (SRL) (columns), according to three diameter classes (<0.5, 0.5-1, and 1-2 mm) (rows), in relation to gap size. ...Context 4
... Materials: The following are available online at https://www.mdpi.com/1999-490 7/12/2/137/s1, Figure S1: Specific root length (SRL) and mean diameter (rows) in relation to gap size of the 1-2 mm diameter fine root class, Table S1: Size of the 15 studied gaps and the related tree-edge characteristics. Data Availability Statement: The datasets generated during the current study are available from the corresponding author on reasonable request. ...Similar publications
Despite the crucial role of fine roots for water and nutrient uptake, soil biological activity and ecosystem carbon cycling, the response of root dynamics to rapidly advancing land-use change in the tropics is still poorly understood. To address this uncertainty, we investigated the consequences of tropical forest conversion to intensively managed...
Citations
... The obtained images were analyzed by WinRhizo Pro V. 2007d (Regent Instruments Inc. Quebec). A color-coded diameter classes method was utilized to accurately measure the length, surface area, and volume of fine roots, according to the protocol described in Amolikondori et al. (2021). Specifically, three sub-classes with diameters less than 2 mm, d < 0.5 mm, 0.5 < d < 1.0, and 1.0 < d < 2.0 mm were set up, and any roots greater than 2 mm were excluded. ...
... In conclusion, outcomes from the present study revealed isohydric behavior rather than specific functional traits as the character that best explains the competitive performance of Q. rubra at the seedling stage. The higher resistance to drought under the low light intensity adopted in this study makes this species highly competitive under the direr conditions in the canopy openings during the summer (Amolikondori et al., 2021). However, the response to the interactive effects of combined stressors may differ from that elicited when the stresses are imposed singly (Mittler, 2006;Suseela et al., 2015), so further experiments combining different light and drought intensities are necessary to elucidate better the growth performance of this alien species in the European habitat. ...
Quercus rubra L. is a moderately shade-tolerant tree species native to eastern North America, readily regenerating since its introduction in the Central and Southern European forests to displace the native pedunculate oak (Quercus robur). Under a scenario of increasing drought, understanding the seedling responses of these two species to water limitation is critical for forest conservation and management. To this aim, morphological, physiological and non-structural carbohydrates analyzes were performed on very-fine and fine roots of Q. robur and Q. rubra seedlings grown under controlled conditions and exposed to two levels of drought before allowing them to recover. Results show significant differences between species for all the investigated traits. The alien Q. rubra showed lower shoot and root biomasses than the native Q. robur, particularly for the thicker fine root 1-2 mm diameter class. However, both species equally invested more biomass in the shoot than the root system (R:S ratio <1). A significant response to drought was observed for the 0.5-1 mm fine root class, with moderate and severe droughted seedlings showing slightly higher biomass than control, particularly in Q. rubra. The overall growth reduction of Q. rubra suggests that the costs associated with the construction and maintenance outweigh the inputs from aboveground, as supported by the lower values of photochemical efficiency (F v /F m), quantum yield (ΦPSII) of PSII and stomatal conductance. In particular, the reduced stomatal conductance assured high midday leaf water potential (i.e., tissue hydration levels) at the expense of growth. The low starch concentration in Q. rubra's very-fine roots correlated positively with the low photochemical efficiency under drought conditions, probably due to the reduction of photosynthate inputs from aboveground. In contrast to the anisohydric behavior reported, these outcomes highlight a rather isohydric behavior for Q. rubra, at least at the seedling stage and in the adopted experimental conditions, making this species highly competitive under the drier condition in the canopy openings during the summer period. Di Iorio A, Caspani AC, Beatrice P and Montagnoli A (2024) Drought-related root morphological traits and non-structural carbohydrates in the seedlings of the alien Quercus rubra and the native Quercus robur: possible implication for invasiveness.
... The biomass of roots constitutes a considerable portion, ranging from 10% to 65%, of the overall biomass of trees [3][4][5]. This substantial root biomass greatly influences the carbon dynamics and storage capacity of forest ecosystems [6][7][8]. At the same time, roots are affected by a combination of factors, including the soil environment in which the plant is located and the tree species itself [5,8]. ...
... This substantial root biomass greatly influences the carbon dynamics and storage capacity of forest ecosystems [6][7][8]. At the same time, roots are affected by a combination of factors, including the soil environment in which the plant is located and the tree species itself [5,8]. Despite their importance, many aspects of roots remain relatively unknown. ...
Aims: Changes in root system architecture (RSA) and soil depth affect the root decomposition rate. However, due to soil opacity, many variables of RSA have not been well studied or even measured. Methods: To investigate the effects of soil depth and the characteristics of RSA on the root decomposition rate, soil samples (Soil cores were collected in October 2020 from Cunninghamia lanceolata and Pinus taeda plantations, which were 40 years old) were obtained using a soil auger and had a diameter of 10 cm and a length of 60 cm. Samples were taken from six different soil depths, ranging from 0 to 60 cm with a 10 cm interval between each depth. The RSA in the in-situ soil cores was analyzed using computed tomography scans and Avizo. Results: Root volume and the number of root throats were significantly higher at the 0–10 cm soil depth than at the 10–60 cm soil depth, but root length was significantly lower at the 50–60 cm soil depth (p < 0.05). Structural equation modeling showed that different stand types influenced root biomass and thus the root decomposition rate directly or indirectly through the characteristics of the stand types. RSA, i.e., root thickness and breadth, affected root biomass indirectly and then affected the root decomposition rate. Root biomass contributed the most to the root decomposition rate in the Cunninghamia lanceolata (20.19%) and Pinus taeda (32.26%) plantations. The contribution of the RSA variables to the root decomposition rate exceeded 50% at the 20–30 cm and 40–50 cm soil depths. Conclusions: Our findings suggested that the influence of the RSA variables on the root decomposition rate varies with soil depth. This deserves more consideration in our future studies on root decomposition and RSA.
... In particular, the exotic species T. distichum showed a more stable metabolism of organic acids, while the native species S. matsudana responded more actively to long-term winter flooding. Amoli Kondori et al. [21] investigated the effect of different sized forest gaps on fine root dynamics and chemical composition six years after logging. These authors highlighted how, in the medium term and within the adopted size range, the fine root system can recover to pre-harvest conditions in terms of standing biomass and morphological traits. ...
The plant fine roots system (i [...]
... For example, previous studies evidenced that pronounced gaps impact the soil temperature and moisture on the forest floor of gap centers [20,21], significantly enhancing the nutrient release (i.e., N, P, and K) and mass loss from litter decomposition during the vegetation period [14,22]. Similarly, N availability in larger gaps in temperate ecosystems is often increased due to modified snow cover, soil freezing, and thawing events-regulating litter decomposition and facilitating nutrient release during the winter [21,23,24]. ...
... Similarly, N availability in larger gaps in temperate ecosystems is often increased due to modified snow cover, soil freezing, and thawing events-regulating litter decomposition and facilitating nutrient release during the winter [21,23,24]. Furthermore, soil N availability in gaps may increase by a reduced uptake by a less dense plant cover [14]-further facilitated by ever-increasing dry and wet N deposition rates in some regions of the world, including northeast China [22]. The responses of species to the variable nutrient supply have been extensively studied [25]. ...
... In contrast, a fast resource acquisition strategy is generally adopted in high resource environments, with fast-growing species featuring root traits linked to rapid soil exploration and uptake of resources such as thin roots with a large surface area and low tissue density [23,24]. Recently, however, gap sizes were reported to affect the chemistry (in particular increasing N and reducing lignin concentrations) rather than the biomass and morphology of the gap-facing fine roots of Fagus orientalis Lipsky [22]. Above ground, increased N availability often significantly decreases LMA and leaf density (LD) while the leaf thickness (LT) increases [26]. ...
Light and nitrogen availability are among the most important environmental factors influencing leaf and root morphological traits and forest ecosystems. Understanding the variation in leaf and root traits is pivotal to the adaptive plasticity and leaf-root-specific traits in response to low light and N availability. The effects of light and N availability on leaf and root traits and their interrelations are still not clear. We aimed to measure the response of leaf and root traits and their interrelations to light and N availability in a temperate region. Thus, a factorial experiment was conducted with two angiosperm tree species under two light (L+, L−) and two nitrogen (N−, N+) levels. Results showed that the leaf density (LD) and leaf mass per area (LMA) increased, while leaf thickness (LT) decreased under low light availability. Under N availability, the LD and LMA decreased, while LT increased in sun-exposed plots and remained stable under low light availability across two species. The root diameter, root length, specific root length (SRL), and specific root area (SRA) decreased, while the root tissue density (TD) increased under low light availability. Root diameter, root length, SRA, and SRL increased, while the TD decreased under N+ in L+ plots and remained stable under L− plots. LMA and LT were significantly positively correlated to root length and SRL while significantly negatively correlated to TD. However, LD was significantly positively correlated to TD. We observed that low light availability has significantly decreased the plant biomass and root mass fraction (RMF) and increased the leaf mass fraction (LMF), while the stem mass fraction (SMF) remained stable―indicating the shade in-tolerances in both species. Correlation analyses revealed that LMF is generally, and particularly under L− conditions, less related to leaf and root morphological traits, while RMF was frequently positively correlated to both leave and root traits under all environmental conditions. This illustrates a divergent regulation of morphological traits above and below ground under varying biomass allocation patterns.