Seasonal nitrogen and carbon concentrations in white, brown and woody fine roots of sugar maple (Acer saccharum Marsh)

Goldfarb, Daniel; Hendrick, Ronald L.; Pregitzer, Kurt S.

doi:10.1007/bf00041381

Cited by 31 publications

(21 citation statements)

References 11 publications

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“…amino acids, organic acids and sugars), and their rate of turnover inside root tissues was greatest in the most actively growing root regions (Jones and Darrah 1996). The higher major nutrient concentrations (N, P, K) in young white roots in comparison to pigmented roots reported here are also consistent with earlier studies showing nutrient translocation from older roots towards more physiologically active parts of the plant (Goldfarb et al 1990;Volder et al 2005). Our study also indicated that older pigmented roots had much greater structural, cell wallassociated C in comparison to younger roots.…”

Section: Discussionsupporting

confidence: 92%

Different ways in which CO2 can be released during the turnover of roots in soil

et al. 2017

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Here, we investigated how root age and mode of death influenced their subsequent turnover and rate of C loss from soil. Young white-coloured and older pigmented roots of Cistus monspeliensis were excised (to simulate death by mechanical severance) or frozen (to simulate death by cell rupture) and immediately buried in soil. CO 2 loss from soil was then measured over time. In a parallel experiment, the rate of CO 2 loss from severed or ruptured roots in the absence of soil was determined. Our results revealed large differences in root chemistry related to age, with young roots having a lower C:N ratio and a greater nutrient content (soluble C, N, P and K). Both root age and mode of death resulted in very different temporal patterns of C release from soil. The amount of C lost from soil followed the series: severed white roots (42.6 ± 3.3 mg C) > ruptured pigmented roots (27.7 ± 0.4 mg C) = ruptured white roots ( 2 7 . 1 ± 0 . 5 m g C ) > s e v e r e d p i g m e n t e d r o o t s (10.1 ± 1.0 mg C) > soil only (3.0 ± 0.2 mg C). Therefore, depending on the treatment, 7 to 41% of the total root-derived C was lost as CO 2 over the duration of the experiment. Comparison with soil-free treatments revealed that the CO 2 release from the severed roots buried in soil was not associated with microbial breakdown but caused by root-induced autophagy in an attempt to keep themselves metabolically active. Ruptured roots also induced a rapid loss of CO 2 which we ascribe to the diffusive loss of root solutes into the soil and subsequent microbial mineralization. Surprisingly, the rate of C loss from soil was greater from the severed root tips than those that were ruptured. Our results imply two distinct routes of C loss dependent on how roots die, one which bypasses the microbial community and one which flows through it.

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Section: Discussionsupporting

confidence: 92%

Different ways in which CO2 can be released during the turnover of roots in soil

et al. 2017

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“…Similarly, Lipp and Andersen (2003) found that white roots of Pinus ponderosa trees comprise a relatively small portion of total root biomass in the field. Classification by root color was frequently used in previous studies, often as proxy for root age, white being regarded as the color of young root segments (Goldfarb et al, 1990;Hendrick and Pregitzer, 1992;Hassan et al, 2008). In this study, however, brown root tips seemed as vital as white ones, and the relatively short duration of the experiment deems it unrealistic that many white root segments already matured to brown terminal roots.…”

Section: 05)mentioning

confidence: 74%

“…Root order class 1 + 2 represents the two terminal root orders (i.e. root tips and the next root segment; additional details on color and root order classification are in Goldfarb et al, 1990, andRewald et al, 2011, respectively) and could be distinguished by color with certainty; we name our classification scheme "extended centripetal root order classification." No spatial segregation between the two different terminal root order classes was noticed.…”

Section: Plant Allometry and Root System Architecturementioning

confidence: 99%

“…Although the dynamics of centripetal systems are opposite to those of root system development, they group functionally similar terminal (most distal) tree segments, such as root tips, into the same order. In addition to those approaches, several researchers have successfully used individual classification parameters to distinguish root segments according to color (Goldfarb et al, 1990;Bouma et al, 2000) or characteristic branching patterns (e.g. cluster roots; Neumann and Martinoia, 2002).…”

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confidence: 99%

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It’s Complicated: Intraroot System Variability of Respiration and Morphological Traits in Four Deciduous Tree Species

2014

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Within branched root systems, a distinct heterogeneity of traits exists. Knowledge about the ecophysiology of different root types is critical to understand root system functioning. Classification schemes have to match functional root types as closely as possible to be used for sampling and modeling. Among ecophysiological root traits, respiration is of particular importance, consuming a great amount of carbon allocated. Root architecture differs between the four deciduous tree seedlings. However, two types of terminal root segments (i.e. first and second orders), white colored and brown colored, can be distinguished in all four species but vary in frequency, their morphology differing widely from each other and higher coarse root orders. Root respiration is related to diameter and tissue density. The use of extended root ordering (i.e. order and color) explains the variance of respiration two times as well as root diameter or root order classes alone. White terminal roots respire significantly more than brown ones; both possess respiration rates that are greater than those of higher orders in regard to dry weight and lower in regard to surface area. The correlation of root tissue density to respiration will allow us to use this continuous parameter (or easier to determine dry matter content) to model the respiration within woody root systems without having to determine nitrogen contents. In addition, this study evidenced that extended root orders are better suited than root diameter classes to picture the differences between root functional types. Together with information on root order class frequencies, these data allow us to calculate realistic, species-specific respiration rates of root branches.

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“…Similarly, nutrient concentration within fine roots varies inversely with root diameter (Goldfarb et aI., 1990;Vogt et aI., 1991). Increase in concentrations of phosphorus, nitrogen, carbon, magnesium, sulphur and sodium with decreasing root diameter is known for Pinus sylvestris (Berg, 1984) and Acer saccharum (Goldfarb et al, 1990). This explains the better capabilities of fine roots as litter than coarse roots.…”

Section: Biochemistry Of Root Litter Degradationmentioning

confidence: 96%

Mycorrhizal Root Litter as a Biofertilizer

Mukerji

Bansal

1999

From Ethnomycology to Fungal Biotechnology

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Seasonal nitrogen and carbon concentrations in white, brown and woody fine roots of sugar maple (Acer saccharum Marsh)

Abstract: Small diameter ( Show more

Cited by 31 publications

References 11 publications

Different ways in which CO2 can be released during the turnover of roots in soil

Different ways in which CO2 can be released during the turnover of roots in soil

It’s Complicated: Intraroot System Variability of Respiration and Morphological Traits in Four Deciduous Tree Species

Mycorrhizal Root Litter as a Biofertilizer

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