Elevated atmospheric CO<sub>2</sub> increases fine root production, respiration, rhizosphere respiration and soil CO<sub>2</sub> efflux in Scots pine seedlings

Janssens, Ivan A.; Crookshanks, Meg; Taylor, Gail; Ceulemans, R.

doi:10.1046/j.1365-2486.1998.00199.x

Cited by 94 publications

(74 citation statements)

References 63 publications

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“…Although similar results have been observed in other ecosystems (George et al 2003, Tjoelker et al 1999, contrary results have also been reported (Janssens et al 1998, Edwards & Norby 1999, BassiriRad et al 1996, making broad statements on how elevated CO 2 affects root respiration difficult to infer. However, nitrogen contents of A. dumosa and L. tridentata roots sampled from the elevated CO 2 plots at the NDFF are not significantly different from those from ambient CO 2 plots (Nowak et al unpublished data), and L. tridentata root nitrogen was also not affected in our greenhouse experiment after 10 months of CO 2 treatment (Table 4).…”

Section: The Nevada Desert Face Facilitysupporting

confidence: 63%

Effects of Elevated Co2 on Root Function and Soil Respiration in a Mojave Desert Ecosystem

Nowak¹

2007

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SUMMARYKey results from our research on responses of plants to elevated atmospheric CO 2 at the Nevada Desert FACE Facility (NDFF) and under controlled environment conditions include: Root Structure and FunctionMeasurements of root physiological characteristics and of arbuscular mycorrhizae indicate that:• Root respiration rates of two Mojave Desert shrubs, Ambrosia dumosa and Larrea tridentata, at the Nevada Desert FACE Facility (NDFF) over five growing seasons and L. tridentata seedlings in a greenhouse experiment were not significantly affected by elevated CO 2 .• The combination of elevated CO 2 and phosphorus reduction in greenhouse studies did not affect root growth or activity.• Specific root length was not significantly affected by CO 2 .• Extraradical hyphae (ERH) of arbuscular mycorrhizal fungi (AMF) varied seasonally, with ERH significantly lower at the end of the year. However, percent root colonization was not affected by sample date. These seasonal patterns of AMF are likely due to greater shrub demands for nutrients early in the year rather than changes in soil moisture.• AMF root colonization or ERH did not vary among soils beneath two shrubs, Ambrosia dumosa and Larrea tridentata, and their associated interspaces.• Beneath L. tridentata, immunoreactive glomalin related soil protein (IRSP) concentrations were significantly greater than all other microsites, and IRSP declined significantly over the year in L. tridentata soils. Significantly higher IRSP concentrations in the spring under L. tridentata may be due to turnover of residual ERH produced in the preceding wet year.• AMF root colonization, ERH lengths, and IRSP concentrations were not different between CO 2 treatments after 9 years of CO 2 treatment for samples collected in the spring and fall from three microsites: beneath Larrea tridentata and Ambrosia dumosa canopies and within shrub interspaces. Thus, our results from both the greenhouse and field experiment suggest that root systems of these species have not altered carbon use for respiration processes on a root length basis, nor have they grown in size to compensate for any nutrient limitations imposed by carbon fertilization. Furthermore, neither species showed increased allocation to arbuscular mycorrhizae under elevated CO 2 . AMF appear to explore all areas of the Mojave Desert equally even though nutrient availability varies considerably among microsites. Stimulated nitrogen cycling by other soil microbes in elevated CO 2 plots may eliminate the need for greater production of AMF by increasing nutrient availability in this system. Root GrowthMinirhizotron measurements of root growth reveal that:• Fine roots accumulate over long time periods in the Mojave Desert.• Elevated CO 2 had transitory effects on the accumulation of fine roots, where standing crop of fine roots accumulated to a larger extent under elevated CO 2 for up to 5 months. 1• The transitory greater accumulation of fine roots under elevated CO 2 was primarily due to lower rates of root loss through time.• After a we...

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Section: The Nevada Desert Face Facilitysupporting

confidence: 63%

Effects of Elevated Co2 on Root Function and Soil Respiration in a Mojave Desert Ecosystem

Nowak¹

2007

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“…In numerous experiments, CO 2 enrichment elicited an increase in the degree of ectomycorrhizal colonization as well as changes in the morphotype assemblages (Godbold & Berntson, 1997;Treseder, 2004;Alberton et al, 2005). Increased root length and thickening of diameter (Janssens et al, 1998, Pritchard et al, 2001) along with enhanced storage of starch in fine roots (Janssens et al, 1998) has been observed under CO 2 enrichment. Whether the reduced SRL in secondary roots is related to an increased accumulation of structural carbohydrates at elevated CO 2 still needs to be demonstrated experimentally.…”

Section: Specific Root Length As a Stress Indicatormentioning

confidence: 98%

“…Vegetation exposed to atmospheric CO 2 enrichment responds by substantially increasing belowground C allocation, directed to the root biomass, particularly to the fine roots (King et al, 1996;Crookshanks et al, 1998, Janssens et al, 1998, Matamala & Schlesinger, 2000Jastrow et al, 2005). The within-root biomass allocation, however, varies from species to species.…”

Section: Specific Root Length As a Stress Indicatormentioning

confidence: 99%

Specific root length as an indicator of environmental change

Ostonen

Püttsepp

Biel

et al. 2007

Plant Biosystems - An International Journal Dealing with all As

530

349

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Specific root length (SRL, m g71 ) is probably the most frequently measured morphological parameter of fine roots. It is believed to characterize economic aspects of the root system and to be indicative of environmental changes. The main objectives of this paper were to review and summarize the published SRL data for different tree species throughout Europe and to assess SRL under varying environmental conditions. Meta-analysis was used to summarize the response of SRL to the following manipulated environmental conditions: fertilization, irrigation, elevated temperature, elevated CO 2 , Al-stress, reduced light, heavy metal stress and physical disturbance of soil. SRL was found to be strongly dependent on the fine root classes, i.e. on the ectomycorrhizal short roots (ECM), and on the roots 50.5 mm, 51 mm, 52 mm and 1 -2 mm in diameter SRL was largest for ECM and decreased with increasing diameter. Changes in soil factors influenced most strongly the SRL of ECM and roots 50.5 mm. The variation in the SRL components, root diameter and root tissue density, and their impact on the SRL value were computed. Meta-analyses showed that SRL decreased significantly under fertilization and Al-stress; it responded negatively to reduced light, elevated temperature and CO 2. We suggest that SRL can be used successfully as an indicator of nutrient availability to trees in experimental conditions.

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“…Numerous studies have shown that the spatial-temporal variation in soil CO 2 effluxes is significant at different scales and is sensitive to environmental factors, such as soil temperature [6,7], soil water [8,9], soil texture [10,11], and root density [12]. Limited information about differentiation and diversities at various scales brings about measurement uncertainties of CO 2 efflux from soil [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Spatial and Temporal Variability of Soil Respiration between Soybean Crop Rows as Measured Continuously over a Growing Season

Wang

Ren

2017

Sustainability

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An improved understanding of temporal and spatial variations in soil respiration is essential for measuring soil CO 2 effluxes accurately. In this study, a field experiment was conducted to investigate the spatial and temporal variability of soil respiration between adjacent crop rows in a soybean (Glycine max L.) field. Soil CO 2 concentration, water content, and temperature at a 7.5 cm depth were recorded continuously at 0 cm, 12 cm, 24 cm, and 35 cm from the plant row during the growing season. Root biomass at the corresponding locations was collected from the 0 to 10 cm and 10 to 20 cm soil layers at three growth stages. Seasonal CO 2 efflux data showed that the minimum value appeared at the seeding stage, increased gradually, reached the maximum at the flowering and grain-filling stages, and then dropped steadily at the mature stage. Within a growth stage, CO 2 effluxes related positively to soil temperature, but negatively to soil water content. In the early and vigorous growing stages of soybean crop, soil respiration showed apparent diurnal variations, and was most significant at the crop row location. Except for the seeding stage, CO 2 effluxes at the crop row were larger than that of other locations, and effluxes at 35 cm from the row were representative of the mean CO 2 efflux between adjacent rows. We concluded that the spatial heterogeneity of CO 2 efflux between crop rows should be taken into consideration when measuring soil respiration in agricultural ecosystems.

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Elevated atmospheric CO₂ increases fine root production, respiration, rhizosphere respiration and soil CO₂ efflux in Scots pine seedlings

Cited by 94 publications

References 63 publications

Effects of Elevated Co2 on Root Function and Soil Respiration in a Mojave Desert Ecosystem

Effects of Elevated Co2 on Root Function and Soil Respiration in a Mojave Desert Ecosystem

Specific root length as an indicator of environmental change

Spatial and Temporal Variability of Soil Respiration between Soybean Crop Rows as Measured Continuously over a Growing Season

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Elevated atmospheric CO2 increases fine root production, respiration, rhizosphere respiration and soil CO2 efflux in Scots pine seedlings

Cited by 94 publications

References 63 publications

Effects of Elevated Co2 on Root Function and Soil Respiration in a Mojave Desert Ecosystem

Effects of Elevated Co2 on Root Function and Soil Respiration in a Mojave Desert Ecosystem

Specific root length as an indicator of environmental change

Spatial and Temporal Variability of Soil Respiration between Soybean Crop Rows as Measured Continuously over a Growing Season

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Elevated atmospheric CO₂ increases fine root production, respiration, rhizosphere respiration and soil CO₂ efflux in Scots pine seedlings