Nitrogen stress alters root proliferation in Douglas-fir seedlings

The proliferation of roots in soil microenvironments was studied to gain an understanding of how nitrogen (N) stress affects root growth. By placing one major lateral root (<10% of the root system) of a Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedling into a small pot (microenvironment) and the remaining roots into a large pot, it was possible to manipulate the growth of a small part of the root system while having only minor effects on the growth of the entire seedling. Nitrogen stress was successfully induced by large-pot treatments and resulted in greatly decreased foliage growth and slightly decreased total fine (<2 mm diam.) root growth. Nitrogen stress had minimal effects on total fine root growth, but large effects on the distribution of growth within the root system. Fine roots grew preferentially in high compared with low N microenvironments, and root proliferation in high N microenvironments was enhanced twofold in N-stressed compared with nonstressed seedlings. The root proliferation response of Douglas-fir seedlings to N stress illustrates a potential means of N-stress compensation. It also implies that root distribution among soil microenvironments may depend not only upon chemical activity of nutrient ions in the rooting environment, but also upon nutrient stress in the whole plant.

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Desiccation Tolerance of Green Ash and Sugar Maple Fine Roots

Journal of Environmental Horticulture ◽

10.24266/0738-2898-27.4.229 ◽

2009 ◽

Vol 27 (4) ◽

pp. 229-233 ◽

Cited By ~ 2

Author(s):

Gary W. Watson

Keyword(s):

Root Growth ◽

Fine Roots ◽

Acer Saccharum ◽

Sugar Maple ◽

Fine Root ◽

Cell Damage ◽

Fraxinus Pennsylvanica ◽

Green Ash ◽

Root Electrolyte Leakage ◽

Bare Root

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.

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Relationship between Very Fine Root Distribution and Soil Water Content in Pre- and Post-Harvest Areas of Two Coniferous Tree Species

Forests ◽

10.3390/f11111227 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1227

Author(s):

Moein Farahnak ◽

Keiji Mitsuyasu ◽

Takuo Hishi ◽

Ayumi Katayama ◽

Masaaki Chiwa ◽

...

Keyword(s):

Water Content ◽

Root System ◽

Soil Water ◽

Soil Water Content ◽

Tree Species ◽

Fine Roots ◽

Fine Root ◽

Soil Depth ◽

Tree Cutting ◽

Coniferous Tree Species

Tree root system development alters forest soil properties, and differences in root diameter frequency and root length per soil volume reflect differences in root system function. In this study, the relationship between vertical distribution of very fine root and soil water content was investigated in intact tree and cut tree areas. The vertical distribution of root density with different diameter classes (very fine <0.5 mm and fine 0.5–2.0 mm) and soil water content were examined along a slope with two coniferous tree species, Cryptomeria japonica (L.f.) D. Don and Chamaecyparis obtusa (Siebold et Zucc.) Endl. The root biomass and length density of very fine roots at soil depth of 0–5 cm were higher in the Ch. obtusa intact tree plot than in the Cr. japonica intact plot. Tree cutting caused a reduction in the biomass and length of very fine roots at 0–5 cm soil depth, and an increment in soil water content at 5–30 cm soil depth of the Ch. obtusa cut tree plot one year after cutting. However, very fine root density of the Cr. japonica intact tree plot was quite low and the soil water content in post-harvest areas did not change. The increase in soil water content at 5–30 cm soil depth of the Ch. obtusa cut tree plot could be caused by the decrease in very fine roots at 0–5 cm soil depth. These results suggest that the distribution of soil water content was changed after tree cutting of Ch. obtusa by the channels generated by the decay of very fine roots. It was also shown that differences in root system characteristics among different tree species affect soil water properties after cutting.

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An In-Situ Rainwater Collection and Infiltration System to Improve Plant-Available Water and Fine Root Growth for Drought Resistance

Applied Engineering in Agriculture ◽

10.13031/aea.13566 ◽

2020 ◽

Vol 36 (5) ◽

pp. 807-814

Author(s):

Xiaolin Song ◽

Xiaodong Gao ◽

Paul Reese Weckler ◽

Wei Zhang ◽

Jie Yao ◽

...

Keyword(s):

Spatial Distribution ◽

Root Growth ◽

Root System ◽

Drought Resistance ◽

Fine Roots ◽

Soil Depth ◽

List Type ◽

Available Water ◽

Plant Available Water

HighlightsAn in-situ rainwater collection and infiltration (RWCI) method is a rainwater catchment utilization techniqueRWCI is advantageous for increasing sustainable plant-avaibale water to increase drought resistanceRWCI significantly increased the amount of water and nutrients in the rhizosphere for uptake by apple tree rootsABSTRACT. A two-year field experiment was undertaken to determine the spatial distribution of plant-available water and roots in soil profiles under two rainfall control systems—an in-situ rainwater collection and infiltration (RWCI) method and a semi-circular basin (SCB)—in apple orchards in the Loess Plateau of China. The results showed that the RWCI treatments with a soil depth of 40 cm (RWCI40), 60 cm (RWCI60), and 80 cm (RWCI80) significantly increased plant-available water in different seasons and depths and increased root growth of apple trees in the experimental soil profile (0–200 cm). At 0–200 cm soil depth, then RWCI treatments had significantly higher (91.86%-110.01%) mean plant-available water storage (PAWS) than the SCB treatment in both study years (2015 and 2016). From 0–120 cm soil depth, the RWCI60 treatment had significantly higher growing season mean PAWS than RWCI40 and RWCI80; however, RWCI80 had the highest from 120–200 cm. From 0–60 cm, the RWCI treatments had 25.84%-36.86% a smaller proportion of root system than the SCB treatment. However, from 60–120 cm, the proportion of root system increased by 131.53% (RWCI40), 157.95% (RWCI60) and 129.98% (RWCI80), relative to SCB. From 0–200 cm, the RWCI treatments had 1.49–1.94 times more root dry weight density than the SCB treatment. The highest concentration of fine roots occurred in the RWCI treatments. Thus, RWCI enabled roots to absorb more water and nutrients from a wider wetted area and improved drought resistance. Keywords: Drought resistance, Fine roots, Loess Plateau, Plant-available water, Spatial distribution.

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Distribution of Fine Roots of Ponderosa Pine and Douglas-Fir in a Central Idaho Forest

Western Journal of Applied Forestry ◽

10.1093/wjaf/23.4.202 ◽

2008 ◽

Vol 23 (4) ◽

pp. 202-205 ◽

Cited By ~ 2

Author(s):

Gabriel Dumm ◽

Lauren Fins ◽

Russell T. Graham ◽

Theresa B. Jain

Keyword(s):

Ponderosa Pine ◽

Root Distribution ◽

Fine Roots ◽

Fine Root ◽

Douglas Fir ◽

Tree Size ◽

Soil Horizon ◽

Soil Horizons ◽

Fine Root Distribution ◽

Root Content

Abstract This study describes soil horizon depth and fine root distribution in cores collected at two distances from the boles of Douglas-fir and ponderosa pine trees at a study site in a central Idaho forest. Concentration and content of fine roots extracted from soil cores were compared among species, soil horizons, tree size, and distance from bole. Approximately 80% of litter and humus samples contained no fine roots. The highest fine root content and concentrations of fine roots occurred in deep mineral soil for both species (1.24 g and 2.82 g/l for Douglas-fir and 0.98g and 2.24 g/l for ponderosa pine, respectively). No statistically significant differences were found in fine root content or concentration between species in any of the four soil horizons. Tree size was not a significant factor in fine root distribution in this study. Significant variables were horizon, distance from bole, and interactions among tree size, location of sample, and soil horizon. This study, which was part of a larger US Forest Service study to develop a predictive model of postfire tree mortality, provides baseline information that may be useful in predicting postfire damage to fine roots.

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SEASONAL CHANGES IN ASPARAGUS ROOT GROWTH IN CONVENTIONAL AND NOTILL SYSTEMS

HortScience ◽

10.21273/hortsci.25.9.1071b ◽

1990 ◽

Vol 25 (9) ◽

pp. 1071b-1071

Author(s):

Daniel Drost ◽

Darlene Wilcox-Lee ◽

Richard Zobel

Keyword(s):

Root Growth ◽

Fine Roots ◽

Fine Root ◽

Production Systems ◽

Growing Season ◽

Published Data ◽

Soil Cores ◽

No Till ◽

Conventional Ct ◽

Fibrous Roots

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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RAINFALL REGIME ON FINE ROOT GROWTH IN A SEASONALLY DRY TROPICAL FOREST

Revista Caatinga ◽

10.1590/1983-21252020v33n218rc ◽

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

Keyword(s):

Root Growth ◽

Root Length ◽

Fine Roots ◽

Root Biomass ◽

Fine Root ◽

Fine Root Biomass ◽

Rainfall Regime ◽

Seasonally Dry ◽

Fine Root Length ◽

Fine Root Growth

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.

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Intraspecific Fine-Root Trait-Environment Relationships across Interior Douglas-Fir Forests of Western Canada

Plants ◽

10.3390/plants8070199 ◽

2019 ◽

Vol 8 (7) ◽

pp. 199 ◽

Cited By ~ 4

Author(s):

Camille E. Defrenne ◽

M. Luke McCormack ◽

W. Jean Roach ◽

Shalom D. Addo-Danso ◽

Suzanne W. Simard

Keyword(s):

Fine Roots ◽

Fine Root ◽

Plant Traits ◽

Regional Scale ◽

Root Traits ◽

Specific Area ◽

Douglas Fir ◽

Western Canada ◽

Chemical Traits ◽

Architectural Traits

Variation in resource acquisition strategies enables plants to adapt to different environments and may partly determine their responses to climate change. However, little is known about how belowground plant traits vary across climate and soil gradients. Focusing on interior Douglas-fir (Pseudotsuga menziesii var. glauca) in western Canada, we tested whether fine-root traits relate to the environment at the intraspecific level. We quantified the variation in commonly measured functional root traits (morphological, chemical, and architectural traits) among the first three fine-root orders (i.e., absorptive fine roots) and across biogeographic gradients in climate and soil factors. Moderate but consistent trait-environment linkages occurred across populations of Douglas-fir, despite high levels of within-site variation. Shifts in morphological traits across regions were decoupled from those in chemical traits. Fine roots in colder/drier climates were characterized by a lower tissue density, higher specific area, larger diameter, and lower carbon-to-nitrogen ratio than those in warmer/wetter climates. Our results showed that Douglas-fir fine roots do not rely on adjustments in architectural traits to adapt rooting strategies in different environments. Intraspecific fine-root adjustments at the regional scale do not fit along a single axis of root economic strategy and are concordant with an increase in root acquisitive potential in colder/drier environments.

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Fine Root Growth of Black Spruce Trees and Understory Plants in a Permafrost Forest Along a North-Facing Slope in Interior Alaska

Frontiers in Plant Science ◽

10.3389/fpls.2021.769710 ◽

2021 ◽

Vol 12 ◽

Author(s):

Kyotaro Noguchi ◽

Yojiro Matsuura ◽

Tomoaki Morishita ◽

Jumpei Toriyama ◽

Yongwon Kim

Keyword(s):

Root Growth ◽

Active Layer ◽

Fine Roots ◽

Fine Root ◽

Black Spruce ◽

Active Layer Thickness ◽

Fine Root Growth ◽

Belowground Carbon ◽

Understory Shrubs ◽

Lower Slope

Permafrost forests play an important role in the global carbon budget due to the huge amounts of carbon stored below ground in these ecosystems. Although fine roots are considered to be a major pathway of belowground carbon flux, separate contributions of overstory trees and understory shrubs to fine root dynamics in these forests have not been specifically characterized in relation to permafrost conditions, such as active layer thickness. In this study, we investigated fine root growth and morphology of trees and understory shrubs using ingrowth cores with two types of moss substrates (feather- and Sphagnum mosses) in permafrost black spruce (Picea mariana) stands along a north-facing slope in Interior Alaska, where active layer thickness varied substantially. Aboveground biomass, litterfall production rate, and fine root mass were also examined. Results showed that aboveground biomass, fine root mass, and fine root growth of black spruce trees tended to decrease downslope, whereas those of understory Ericaceae shrubs increased. Belowground allocation (e.g., ratio of fine root growth/leaf litter production) increased downslope in both of black spruce and understory plants. These results suggested that, at a lower slope, belowground resource availability was lower than at upper slope, but higher light availability under open canopy seemed to benefit the growth of the understory shrubs. On the other hand, understory shrubs were more responsive to the moss substrates than black spruce, in which Sphagnum moss substrates increased fine root growth of the shrubs as compared with feather moss substrates, whereas the effect was unclear for black spruce. This is probably due to higher moisture contents in Sphagnum moss substrates, which benefited the growth of small diameter (high specific root length) fine roots of understory shrubs. Hence, the contribution of understory shrubs to fine root growth was greater at lower slope than at upper slope, or in Sphagnum than in feather-moss substrates in our study site. Taken together, our data show that fine roots of Ericaceae shrubs are a key component in belowground carbon flux at permafrost black spruce forests with shallow active layer and/or with Sphagnum dominated forest floor.

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Reverse conductivity for water transport and related anatomy in fine roots of six temperate tree species – a potential limitation for hydraulic redistribution

Journal of Plant Hydraulics ◽

10.20870/jph.2019.1-8 ◽

2019 ◽

Vol 6 ◽

Cited By ~ 2

Author(s):

Benjamin Hesse ◽

Thorsten Grams ◽

Benjamin Hafner

Keyword(s):

Water Potential ◽

Root System ◽

Tree Species ◽

Fine Roots ◽

Fine Root ◽

Reverse Flow ◽

Root Anatomy ◽

Hydraulic Redistribution ◽

Acer Pseudoplatanus ◽

Secondary Roots

Hydraulic redistribution (HR), the passive reallocation of water along plant structures following a water potential gradient, is an important mechanism for plant survival under drought. For example, trees with deeper roots reallocate water from deeper moist to shallower, drier soil layers sustaining their upper fine root system. The relevance of HR for temperate forest ecosystems is hardly investigated. Both environmental and tree internal factors limiting the capacity for HR, such as low water potential gradients or root anatomy, respectively, are not well understood. Here we investigate fine root anatomy and related capacity for reverse flow of water of six temperate tree species, i.e. Acer pseudoplatanus, Castanea sativa, Fagus sylvatica, Picea abies, Pseudotsuga menziesii and Quercus robur both in forward and reverse flow direction. Additionally, anatomy of primary and secondary roots was analyzed, to test the hypotheses that root anatomy is similar in primary and secondary roots (H1) and conductivity for forward and reverse flow of water in fine roots is identical (H2). In contrast to the two gymnosperm species, most anatomical parameters, e.g. hydraulic conduit diameter and conduit density, were distinctly different between primary and secondary roots in the angiosperms. Therefore, H1 was rejected for angiosperm trees. The reverse flow of water in fine roots was reduced by approx. 40 % compared to the forward flow in angiosperms, while there was no difference in the gymnosperms. Thus, H2 was rejected for angiosperms. This reduction may be caused by vessel structure (e.g. tapering or secondary thickening elements), or perforation plate and pit architecture (e.g. width of aperture opening). Because of the reduced conductivity of reverse water flow, the ability of angiosperm trees to redistribute water along their root system might be lower than expected.

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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 ◽

10.3390/f11050528 ◽

2020 ◽

Vol 11 (5) ◽

pp. 528

Author(s):

Zana A. Lak ◽

Hans Sandén ◽

Mathias Mayer ◽

Douglas L. Godbold ◽

Boris Rewald

Keyword(s):

Root Growth ◽

Interspecific Competition ◽

Intraspecific Competition ◽

Fine Roots ◽

Root Biomass ◽

Extracellular Enzymes ◽

Fine Root ◽

Root Traits ◽

Acer Pseudoplatanus ◽

High Plasticity

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.

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