Root Physiology – from Gene to Function

Lambers, Hans; Colmer, Timothy D.

doi:10.1007/s11104-005-0964-x

Cited by 14 publications

(14 citation statements)

References 95 publications

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“…The mechanism by which enzyme activity decreases or increases with pH is not well known, although the mechanisms of enzyme regulation associated with several environmental (salt, drought, heat) and nutritional factors are well understood (Lambers and Colmer 2005;Xu et al 2012). In this study, low pH significantly reduced NR and NiR enzyme activities in both species.…”

Section: N Assimilationmentioning

confidence: 61%

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Distinct effect of pH on N uptake and assimilation in two conifer species

Meng

Zhang

Су

et al. 2016

Trees

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Key message Prince Rupprecht's Larch from the Loess Plateau takes up and assimilates a greater proportion of N as NO 3 2 , particularly at neutral pH, whereas Chinese Fir assimilates a greater proportion of N as NH 4 1 , particularly at low pH levels.Abstract The effects of pH on nitrate and ammonium uptake and assimilation in two coniferous species were compared. Prince Rupprecht's Larch (Larix principis-rupprechtii Mayr) grows on the loess plateau in alkaline soils with low available nitrogen (N), whereas Chinese Fir (Cunninghamia lanceolata) grows in acidic soils. In the present study, the net fluxes in ammonium (NH 4 ? ) and nitrate (NO 3 2 ) were measured using a non-invasive microelectrode ion flux measurement system, and the expression of NH 4 ? and NO 3 2 transporters (AMTs and NRTs, respectively) as well as H ? -ATPase was examined to provide insights into the N uptake mechanisms in Prince Rupprecht's Larch and Chinese Fir. The enzyme assays involved in N assimilation were also determined. For Prince Rupprecht's Larch, low pH (pH 4) resulted in a decrease in net ammonium uptake, which remained unchanged in Chinese Fir. Net nitrate uptake in Prince Rupprecht's Larch and Chinese Fir was much lower in soils with pH 4 relative to those with pH 7. Low pH significantly decreased the H ? -ATPase activity and the expression level of NRTs in roots of Prince Rupprecht's Larch. However, the expression level of AMTs in Prince Rupprecht's Larch was significantly higher at pH 7 than at pH 4. The H ? -ATPase activity in roots of Chinese Fir remained unaltered in response to changes in pH, and the transcript abundances of AMTs and NRTs were down-regulated by low pH. Low pH decreased N assimilation in both conifer species with the exception of NH 4 ? assimilation in Chinese Fir, which displayed higher glutamine synthetase (GS) and glutamate synthetase (GOGAT activities) at low pH. Prince Rupprecht's Larch from the Loess Plateau takes up and assimilates a greater proportion of N as NO 3 2 , particularly at neutral pH, whereas Chinese Fir assimilates a greater proportion of N as NH 4 ? , particularly at low pH levels. This study contributes to our understanding of nitrogen metabolism mechanisms in response to pH changes.

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Section: N Assimilationmentioning

confidence: 61%

“…in forest soils (Lucash et al 2005). Soils tend to possess an overall negative charge, which allows NO 3 -to move freely, and NO 3 -is also easily lost from the root zone through leaching because of its high diffusion coefficient in soil (Lambers and Colmer 2005).…”

Section: Following Forest Disturbance Nhmentioning

confidence: 99%

Distinct effect of pH on N uptake and assimilation in two conifer species

Meng

Zhang

Су

et al. 2016

Trees

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“…Moreover, the phosphate concentrations in Pistia stratiotes container (non aeration and aeration) were reduced from 32.5 mg/L to 21 mg/L and 17.5 mg/L respectively. Phosphate acquired by roots is rapidly loaded into the xylem and it moves upward in shoots where it is unloaded into growing sinks (Lambers and Colmer 2005). In the 4th week, the phosphate concentration for treatment container with Eichhornia crassipes (non aeration and aeration) was increased from 4.87 mg/L to 7 mg/L and 5 to 5.33 mg/L while phosphate concentration for treatment container with Pistia stratiotes (non aeration and aeration) was increased from 9.87 mg/L to 14.8 mg/L and 8.83 mg/L to 14.33 mg/L respectively due to accumulation of detritus plant.…”

Section: Chemical Constituents Of the Wastewatersmentioning

confidence: 99%

ASSESSING WATER HYACINTH (EICHHORNIA CRASSOPES) AND LETTUCE (PISTIA STRATIOTES)EFFECTIVENESS IN AQUACULTURE WASTEWATER TREATMENT

Akinbile¹,

Yusoff²

2012

International Journal of Phytoremediation

137

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Water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) were analyzed to determine their effectiveness in aquaculture wastewater treatment in Malaysia. Wastewater from fish farm in Semanggol Perak, Malaysia was sampled and the parameters determined included, the pH, turbidity, dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), nitrite phosphate (PO4(3-)), nitrate (NO(3-)), nitrite (NO(-2)), ammonia (NH3), and total kjedahl nitrogen (TKN). Also, hydroponics system was set up and was added with fresh plants weights of 150 +/- 20 grams Eichhornia crassipes and 50 +/- 10 grams Pistia stratiotes during the 30 days experiment. The phytoremediation treatment with Eichhornia crassipes had pH ranging from 5.52 to 5.59 and from 4.45 to 5.5 while Pistia stratiotes had its pH value from 5.76 to 6.49 and from 6.24 to 7.07. Considerable percentage reduction was observed in all the parameters treated with the phytoremediators. Percentage reduction of turbidity for Eichhornia crassipes were 85.26% and 87.05% while Pistia stratiotes were 92.70% and 93.69% respectively. Similar reductions were observed in COD, TKN, NO(3-), NH3, and PO4(3-). The capability of these plants in removing nutrients was established from the study. Removal of aquatic macrophytes from water bodies is recommended for efficient water purification.

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“…A key difference between exudation by cluster and normal roots is related to the fact that cluster root exudation occurs at the same location whereas the main region of exudation by normal roots moves through the soil as the root elongates (Skene 2003). It is the combination of the cluster root capacity to release carboxylates in an exudative burst and their morphological structure that allows the build-up of high concentrations in the rhizosphere (Lambers and Colmer 2005).…”

Section: Root Exudation By Cluster Rootsmentioning

confidence: 99%

Spatial and temporal variation in organic acid anion exudation and nutrient anion uptake in the rhizosphere of Lupinus albus L.

et al. 2007

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We investigated in situ the temporal patterns and spatial extent of organic acid anion exudation into the rhizosphere solution of Lupinus albus, and its relation with the nutrient anions phosphate, nitrate and sulfate by means of a rhizobox micro suction cup method under P sufficient conditions. We compared the soil solution in the rhizosphere of cluster roots with that in the vicinity of normal roots, nodules and bulk soil. Compared to the other rhizosphere and soil compartments, concentrations of organic acid anions were higher in the vicinity of cluster roots during the exudative burst (citrate, oxalate) and nodules (acetate, malate), while concentrations of inorganic nutrient anions were highest in the bulk soil. Both active cluster roots and nodules were most efficient in taking up nitrate and phosphate. The intensity of citrate exudation by cluster roots was highly variable. The overall temporal patterns during the lifetime of cluster roots were overlaid by a diurnal pattern, i.e. in most cases, the exudation burst consisted of one or more peaks occurring in the afternoon. Multiple exudation peaks occurred daily or were separated by 1 or 2 days. Although citrate concentrations decreased with distance from the cluster root apex, they were still significantly higher at a distance of 6 to 10 mm than in the bulk soil. Phosphate concentrations were extremely variable in the proximity of cluster roots. While our results indicate that under P sufficient conditions cluster roots take up phosphate during their entire life time, the influence of citrate exudation on phosphate mobilization from soil could not be assessed conclusively because of the complex interactions between P uptake, organic acid anion exudation and P mobilization. However, we observed indications of P mobilization concurrent with the highest measured citrate concentrations. In conclusion, this study provides semiquantitative in situ data on the reactivity of different root segments of L. albus L. in terms of root exudation and nutrient uptake under nutrient sufficient conditions, in particular on the temporal variability during the lifetime of cluster roots.

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Root Physiology – from Gene to Function

Cited by 14 publications

References 95 publications

Distinct effect of pH on N uptake and assimilation in two conifer species

Distinct effect of pH on N uptake and assimilation in two conifer species

ASSESSING WATER HYACINTH (EICHHORNIA CRASSOPES) AND LETTUCE (PISTIA STRATIOTES)EFFECTIVENESS IN AQUACULTURE WASTEWATER TREATMENT

Spatial and temporal variation in organic acid anion exudation and nutrient anion uptake in the rhizosphere of Lupinus albus L.

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