The interactive impact of root branch order and soil genetic horizon on root respiration and nitrogen concentration

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.

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Endogenous and exogenous controls of root life span, mortality and nitrogen flux in a longleaf pine forest: root branch order predominates

Journal of Ecology ◽

10.1111/j.1365-2745.2008.01385.x ◽

2008 ◽

Vol 96 (4) ◽

pp. 737-745 ◽

Cited By ~ 119

Author(s):

Dali Guo ◽

Robert J. Mitchell ◽

Jennifer M. Withington ◽

Ping-Ping Fan ◽

Joseph J. Hendricks

Keyword(s):

Life Span ◽

Longleaf Pine ◽

Pine Forest ◽

Nitrogen Flux ◽

Branch Order ◽

Root Branch Order ◽

Root Life Span

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Root respiration in North American forests: effects of nitrogen concentration and temperature across biomes

Oecologia ◽

10.1007/s00442-002-0931-7 ◽

2002 ◽

Vol 131 (4) ◽

pp. 559-568 ◽

Cited By ~ 171

Author(s):

A. Burton ◽

K. Pregitzer ◽

R. Ruess ◽

R. Hendrick ◽

M. Allen

Keyword(s):

North American ◽

Root Respiration ◽

Nitrogen Concentration

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Effect of nitrogen fertilizer, root branch order and temperature on respiration and tissue N concentration of fine roots in Larix gmelinii and Fraxinus mandshurica

Tree Physiology ◽

10.1093/treephys/tpr057 ◽

2011 ◽

Vol 31 (7) ◽

pp. 718-726 ◽

Cited By ~ 23

Author(s):

S. Jia ◽

Z. Wang ◽

X. Li ◽

X. Zhang ◽

N. B. Mclaughlin

Keyword(s):

Nitrogen Fertilizer ◽

Fine Roots ◽

Larix Gmelinii ◽

Fraxinus Mandshurica ◽

Branch Order ◽

Root Branch Order ◽

N Concentration

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Linking root morphology, longevity and function to root branch order: a case study in three shrubs

Plant and Soil ◽

10.1007/s11104-010-0466-3 ◽

2010 ◽

Vol 336 (1-2) ◽

pp. 197-208 ◽

Cited By ~ 19

Author(s):

Gang Huang ◽

Xue-yong Zhao ◽

Ha-lin Zhao ◽

Ying-xin Huang ◽

Xiao-an Zuo

Keyword(s):

Root Morphology ◽

Branch Order ◽

Root Branch Order ◽

And Function

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Does root respiration in Australian rainforest tree seedlings acclimate to experimental warming?

Tree Physiology ◽

10.1093/treephys/tpaa056 ◽

2020 ◽

Vol 40 (9) ◽

pp. 1192-1204

Author(s):

Nam Jin Noh ◽

Kristine Y Crous ◽

Jinquan Li ◽

Zineb Choury ◽

Craig V M Barton ◽

...

Keyword(s):

Root Respiration ◽

Nitrogen Concentration ◽

Temperature Response ◽

Temperature Acclimation ◽

Thermal Acclimation ◽

Root Tissue ◽

Tropical Species ◽

Tree Seedlings ◽

Tissue Density ◽

Root Tissue Density

Abstract Plant respiration can acclimate to changing environmental conditions and vary between species as well as biome types, although belowground respiration responses to ongoing climate warming are not well understood. Understanding the thermal acclimation capacity of root respiration (Rroot) in relation to increasing temperatures is therefore critical in elucidating a key uncertainty in plant function in response to warming. However, the degree of temperature acclimation of Rroot in rainforest trees and how root chemical and morphological traits are related to acclimation is unknown. Here we investigated the extent to which respiration of fine roots (≤2 mm) of four tropical and four warm-temperate rainforest tree seedlings differed in response to warmer growth temperatures (control and +6 °C), including temperature sensitivity (Q10) and the degree of acclimation of Rroot. Regardless of biome type, we found no consistent pattern in the short-term temperature responses of Rroot to elevated growth temperature: a significant reduction in the temperature response of Rroot to +6 °C treatment was only observed for a tropical species, Cryptocarya mackinnoniana, whereas the other seven species had either some stimulation or no alteration. Across species, Rroot was positively correlated with root tissue nitrogen concentration (mg g−1), while Q10 was positively correlated with root tissue density (g cm−3). Warming increased root tissue density by 20.8% but did not alter root nitrogen across species. We conclude that thermal acclimation capacity of Rroot to warming is species-specific and suggest that root tissue density is a useful predictor of Rroot and its thermal responses in rainforest tree seedlings.

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