scholarly journals Plasticity of Root Traits under Competition for a Nutrient-Rich Patch Depends on Tree Species and Possesses a Large Congruency between Intra- and Interspecific Situations

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 528
Author(s):  
Zana A. Lak ◽  
Hans Sandén ◽  
Mathias Mayer ◽  
Douglas L. Godbold ◽  
Boris Rewald

Belowground competition is an important structuring force in terrestrial plant communities. Uncertainties remain about the plasticity of functional root traits under competition, especially comparing interspecific vs. intraspecific situations. This study addresses the plasticity of fine root traits of competing Acer pseudoplatanus L. and Fagus sylvatica L. seedlings in nutrient-rich soil patches. Seedlings’ roots were grown in a competition chamber experiment in which root growth (biomass), morphological and architectural fine roots traits, and potential activities of four extracellular enzymes were analyzed. Competition chambers with one, two conspecific, or two allospecific roots were established, and fertilized to create a nutrient ‘hotspot’. Interspecific competition significantly reduced fine root growth in Fagus only, while intraspecific competition had no significant effect on the fine root biomass of either species. Competition reduced root nitrogen concentration and specific root respiration of both species. Potential extracellular enzymatic activities of β-glucosidase (BG) and N-acetyl-glucosaminidase (NAG) were lower in ectomycorrhizal Fagus roots competing with Acer. Acer fine roots had greater diameter and tip densities under intraspecific competition. Fagus root traits were generally more plastic than those of Acer, but no differences in trait plasticity were found between competitive situations. Compared to Acer, Fagus roots possessed a greater plasticity of all studied traits but coarse root biomass. However, this high plasticity did not result in directed trait value changes under interspecific competition, but Fagus roots grew less and realized lower N concentrations in comparison to competing Acer roots. The plasticity of root traits of both species was thus found to be highly species- but not competitor-specific. By showing that both con- and allospecific roots had similar effects on target root growth and most trait values, our data sheds light on the paradigm that the intensity of intraspecific competition is greater than those of interspecific competition belowground.

2020 ◽  
Author(s):  
Dan-Dan Li ◽  
Hong-Wei Nan ◽  
Chun-Zhang Zhao ◽  
Chun-Ying Yin ◽  
Qing Liu

Abstract Aims Competition, temperature, and nutrient are the most important determinants of tree growth in the cold climate on the eastern Tibetan Plateau. Although many studies have reported their individual effects on tree growth, little is known about how the interactions of competition with fertilization and temperature affect root growth. We aim to test whether climate warming and fertilization promote competition and to explore the functional strategies of Picea asperata in response to the interactions of these factors. Methods We conducted a paired experiment including competition and non-competition treatments under elevated temperature (ET) and fertilization. We measured root traits, including the root tip number over the root surface (RTRS), the root branching events over the root surface (RBRS), the specific root length (SRL), the specific root area (SRA), the total fine root length and area (RL and RA), the root tips (RT) and root branching events (RB). These root traits are considered to be indicators of plant resource uptake capacity and root growth. The root biomass and the nutrient concentrations in the roots were also determined. Important Findings The results indicated that ET, fertilization and competition individually enhanced the nitrogen (N) and potassium (K) concentrations in fine roots, but they did not affect fine root biomass or root traits, including RL, RT, RA and RB. However, both temperature and fertilization, as well as their interaction, interacting with competition increased RL, RA, RT, RB, and nutrient uptake. In addition, the SRL, SRA, RTRS and RBRS decreased under fertilization, the interaction between temperature and competition decreased SRL and SRA, while the other parameters were not affected by temperature or competition. These results indicate that Picea asperata maintains a conservative nutrient strategy in response to competition, climate warming, fertilization, and their interactions. Our results improve our understanding of the physiological and ecological adaptability of trees to global change.


2020 ◽  
Vol 33 (2) ◽  
pp. 458-469
Author(s):  
EUNICE MAIA DE ANDRADE ◽  
GILBERTO QUEVEDO ROSA ◽  
ALDENIA MENDES MASCENA DE ALMEIDA ◽  
ANTONIO GIVANILSON RODRIGUES DA SILVA ◽  
MARIA GINA TORRES SENA

ABSTRACT Seasonally dry tropical forests (SDTF) usually present dry seasons of eight or more months. Considering the concerns about the resilience of SDTF to climate changes, the objective of this study was to evaluate the effect of the rainfall regime on fine root growth in a SDTF. The experiment started at the end of the wet season (July 2015), when fine roots were evaluated and ingrowth cores were implemented. The temporal growth of fine roots in the 0-30 cm soil layer was monitored, considering the 0-10, 10-20, and 20-30 cm sublayers, through six samplings from November 2015 to July 2017. The characteristics evaluated were fine root biomass, fine root length, fine root specific length, and fine root mean diameter. The significances of the root growths over time and space were tested by the Kruskal-Wallis test (p<0.05). Fine roots (Ø<2 mm) were separated and dried in an oven (65 °C) until constant weight. The root length was determined using the Giaroots software. The fine root biomass in July 2015 was 7.7±5.0 Mg ha-1 and the length was 5.0±3.2 km m-2. Fine root growth in SDTF is strongly limited by dry periods, occurring decreases in biomass and length of fine roots in all layers evaluated. Fine root growth occurs predominantly in rainy seasons, with fast response of the root system to rainfall events, mainly in root length.


1998 ◽  
Vol 78 (1) ◽  
pp. 163-169 ◽  
Author(s):  
J. S. Bhatti ◽  
N. W. Foster ◽  
P. W. Hazlett

Vertical distribution of fine root biomass and nutrient content was examined within a black spruce (Picea mariana) stand growing on a boreal peat soil in northeastern Ontario. The influence of site physical and chemical properties on fine root biomass production was assessed. More then 80% of the fine roots were present in moss plus the top 10 cm of peat where nutrients and aeration are most favourable. The fine root biomass (W/V) was significantly higher with alder (5.9 kg m−3) (Alnus rugosa) as understory vegetation compared to non-alder locations (2.9 kg m−3). Total nutrient content in fine roots was 54, 3.2, 5.4, 63 and 5.7 kg ha−1 on the alder site and 20, 1.4, 2.3, 28 and 4.2 kg ha−1 of N, P, K, Ca, and Mg on the non-alder site, respectively. The mass (W/V) of nutrients in fine roots was strongly dependent upon the availability of nutrients in the peat. Fine root content had a strong positive relationship with peat available P and exchangeable K contents suggesting that P and K may be limiting nutrients for black spruce in this peat soil. Key words: Nitrogen, phosphorus, potassium, boreal peatlands, aeration, water table


2009 ◽  
Vol 27 (4) ◽  
pp. 229-233 ◽  
Author(s):  
Gary W. Watson

Abstract Exposed fine roots are subject to desiccation, which may affect their survival as well as new root growth following bare root transplanting. Fine roots of dormant 1-year-old green ash (Fraxinus pennsylvanica) and sugar maple (Acer saccharum) seedlings, subjected to desiccation treatments of 0, 1, 2, or 3 hours in December and March, lost up to 82 percent of their water. Root electrolyte leakage, a measure of cell damage, tripled after three hours of desiccation. The increase was moderately, but significantly, greater in March for both species. Desiccation treatments had no effect on fine root survival. Growth of new roots (RGP) was also unaffected by desiccation treatments. RGP of maple was greater in March than December, but not ash.


2009 ◽  
Vol 55 (No. 12) ◽  
pp. 556-566 ◽  
Author(s):  
B. Konôpka

Interspecific comparisons of the fine root “behaviour” under stressful situations may answer questions related to resistance to changing environmental conditions in the particular tree species. Our study was focused on Norway spruce (<I>Picea abies</I> [L.] Karst.) and European beech (<I>Fagus sylvatica</I> L.) grown in an acidic soil where acidity was caused by past air pollution in the Kysucké Beskydy Mts., North-Western Slovakia. Between April and October 2006, the following fine root traits were studied: biomass and necromass seasonal dynamics, vertical distribution, production, mortality, fine root turnover and production to mortality ratio. Sequential soil coring was repeatedly implemented in April, June, July, September, and October including the soil layers of 0–5, 5–15, 15–25, and 25–35 cm. Results indicated that spruce had a lower standing stock of fine roots than beech, and fine roots of spruce were more superficially distributed than those of beech. Furthermore, we estimated higher seasonal dynamics and also higher turnover of fine roots in spruce than in beech. The production to mortality ratio was higher in beech than in spruce, which was hypothetically explained as the effect of drought episodes that occurred in July and August. The results suggested that the beech root system could resist a physiological stress better than that of spruce. This conclusion was supported by different vertical distributions of fine roots in spruce and beech stands.


2020 ◽  
Vol 25 (1) ◽  
pp. 24-29
Author(s):  
Krishna Prasad Bhattarai ◽  
Tej Narayan Mandal ◽  
Tilak Prasad Gautam

The present study was conducted to understand the effect of altitude on the nutrient concentration, nutrient stock, and uptake in the fine root of the Terai Sal forest (TSF) and Hill Sal forest (HSF) in eastern Nepal. Annual mean fine root biomass in 0-30 cm soil depth was found higher in HSF (6.27 Mg ha-1) than TSF (5.05 Mg ha-1). Conversely, fine root production was higher in TSF (4.8 Mg ha-1 y-1) than HSF (4.12 Mg ha-1 y-1). Nitrogen, phosphorus, and potassium content in fine roots were slightly higher in TSF than HSF. Nutrient concentration in fine roots of smaller size (<2 mm diameter) was nearly 1.2 times greater than that of larger size (2–5 mm diameter) in both forests. In HSF total stock of different nutrients (kg ha-1) in fine root was 55.62 N, 4.99 P, and 20.15 K whereas, these values were 49.49 N, 4.14 P, and 19.27 K only in TSF. However, total nutrient uptake (kg ha-1y-1) by fine root (both size classes) was greater in TSF (48.5 N, 4.3 P, and 18.6 K) than HSF (36.9 N, 3.3 P, and 13.5 K). The variability in fine root nutrient dynamics between these two forests was explained by the differences in fine root biomass and production which were influenced by the combined effect of varied altitude and season. The fine root, as being a greater source of organic matter, the information on its nutrient dynamics is inevitable for the management of soil nutrients in the forest ecosystem.


1986 ◽  
Vol 16 (6) ◽  
pp. 1360-1364 ◽  
Author(s):  
S. K. Srivastava ◽  
K. P. Singh ◽  
R. S. Upadhyay

Temporal variations in the spatial distribution of fine root mass were studied in a 19-year-old teak plantation in a dry tropical region. The soil block method was used to investigate fine root dynamics. Quantification of fine root mass was achieved in terms of live teak roots (separated by diameter), dead teak roots, teak root bark, herb roots, and fragmented soil organic matter. The annual mean fine root biomass was 5420 kg•ha−1 and the net production was 5460 kg•ha−1•year−1. The bulk of the root mass was distributed at a depth of 10–30 cm and roots ≤2 mm constituted one-half or more of the total root biomass. Maximum live root growth occurred during the rainy season. All root sizes showed similar bimodal seasonal patterns, but the maximum:minimum ratio generally declined with greater root size.


2021 ◽  
Author(s):  
Li Ji ◽  
Yue Liu ◽  
Jun Wang ◽  
Zhimin Lu ◽  
Yuchun Yang ◽  
...  

Non-structural carbohydrates (NSCs) facilitate plants adapt to drought stress, could characterize trees growth and survival ability and buffer against external disturbances. Previous studies have focused on the distribution and dynamics of NSCs among different plant organs under drought conditions. However, discussion about the NSC levels of fine roots in different root branch order were little, especially the relationship between fine root trait variation and NSCs content. The aim of the study is to shed light into the synergistic variation of fine root traits and NSC content in different root branch order under different drought and soil substrate conditions. 2-year-old Fraxinus mandshurica Rupr. potted seedlings were planted in three different soil substrates (humus, loam and sandy-loam soil) and conducted to four drought intensities (CK, mild drought, moderate drought and severe drought) for two months. With the increase of drought intensity, the biomass of fine roots decreased significantly. Under the same drought intensity, seedlings in sandy-loam soil have higher root biomass, and the coefficient of variation of fifth-order roots (37.4%, 44.5% and 53.0% in humus, loam and sandy loam, respectively) is higher than that of lower-order roots. With the increase of drought intensity, the specific root length (SRL) and average diameter (AD) of all five orders increased and decreased, respectively. The fine roots in humus soil had higher soluble sugar content and lower starch content. Also, the soluble sugar and starch content of fine roots showed decreasing and increasing tendency respectively. Soluble sugar and starch explain the highest degree of total variation of fine root traits, that is 32.0% and 32.1% respectively. With ascending root order, the explanation of the variation of root traits by starch decreased (only 6.8% for fifth-order roots). The response of different root branch order fine root morphological traits of F. mandshurica seedlings to resource fluctuations ensures that plants maintain and constructure the root development by an economical way to obtain more resources.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1071b-1071
Author(s):  
Daniel Drost ◽  
Darlene Wilcox-Lee ◽  
Richard Zobel

Published data on the spatial patterns and periodicity of root growth in asparagus are limited. During the 1989 growing season growth and distribution of both fleshy and fibrous roots were monitored in a 7 year old asparagus planting. Soil cores were removed at 15 cm intervals to a depth of 90 cm at 40 and 80 cm from the plants in asparagus beds which had been maintained under conventional (CT) and no-till (NT) production systems. Fleshy and fine roots were separated from the soil and root length densities calculated. Harvests began in late March and continued at three week intervals until early November. Fine root growth was greater in the NT than CT in all depths and at both locations in March. Greatest lengths of fine roots were at the 15-60 cm depths for both CT and NT. This pattern was consistent throughout the season. Fine root lengths decreased by one half by the middle of the year (July) and remained at those levels until the last harvest (Nov). Fleshy root lengths were more variable, however NT generally had greater lengths than CT. Greatest length of fleshy roots were located in the 15-60 cm depths for both CT and NT treatments. Few fleshy roots were found below the 60 cm depth.


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