Root exudates as mediators of mineral acquisition in low-nutrient environments

Dakora, Felix D.; Phillips, Donald A.

doi:10.1007/978-94-017-1570-6_23

Cited by 554 publications

(600 citation statements)

References 79 publications

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“…Generally, crop plants have various strategies to influence either the spatial or the chemical availability of P in soil. Some plants adapt to low-P soil by changing their root morphology to explore a large soil volume, other excrete P-solubilizing compounds like organic acids, organic and inorganic ions, sugars, vitamins, nucleosides, and enzymes (Staunton and Leprince 1996;Dakora and Phillips 2002;Nurruzzaman et al 2006).…”

Section: Resultsmentioning

confidence: 99%

Biomass ashes and their phosphorus fertilizing effect on different crops

Schiemenz

Eichler‐Löbermann

2010

Nutr Cycl Agroecosyst

116

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The reutilization of biomass ashes in agriculture is an important issue to create nutrient cycles and to save fertilizer. To analyse the P fertilization effect of crop biomass ashes (rape meal ash (RMA), straw ash (SA), and cereal ash (CA)) in interaction with different crops, two pot experiments with a poor loamy sand deficient in P were carried out. Besides the three ash treatments, other treatments included triple superphosphate (TSP) as a high soluble P source, potassium chloride (KCl) as a high soluble K source, and a control (CON) without P and K. The main crops (maize, lupin, summer barley, and oilseed rape) were cultivated in the first experiment from April to May and the catch crops (oil radish, phacelia, italian ryegrass, and buckwheat) were cultivated in the second experiment from August to September. Plant parameters (biomass and P uptake of shoots), soil pH, different P pools of the soil (total P (Pt), water soluble P (Pw), double lactate soluble P (Pdl), oxalate soluble P (Pox)), P sorption capacity (PSC), and the degree of P saturation (DPS) were investigated. The fertilization effect of biomass ashes was comparable with that of TSP. On average of all crops, the highest P uptake (86.7 mg pot -1 ) was found after RMA application, and the lowest P uptake (66.6 mg pot -1 ) for CON. The readily bio-available soil P contents (Pw and Pdl) were significantly increased when P was supplied, regardless of whether P was given with ash or with high soluble TSP. The P fertilization effects also depended on the cultivated crops. The ash treatments resulted in highest increases of soil Pw values when combined with buckwheat cultivation. After buckwheat harvest the Pw content in the control was 8.0 mg kg -1 , and in the ash treatments between 13.9 mg kg -1 (CA) and 15.7 mg kg -1 (RMA). From the results of this study we conclude, that crop biomass ashes can be an adequate P source comparable to that of highly soluble commercial P fertilizer.

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Section: Resultsmentioning

confidence: 99%

Biomass ashes and their phosphorus fertilizing effect on different crops

Schiemenz

Eichler‐Löbermann

2010

Nutr Cycl Agroecosyst

116

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“…In parallel with this change, biochemical changes have been observed, including proton extrusion by the activation of a proton-pump H + -ATPase, thereby reducing soil pH and increasing the solubility of Fe 3+ Waters et al, 2002;Hell and Stephan, 2003;Schmidt, 2003;Santi et al, 2005). Concomitantly, organic acids such as citric and malic acids that act as Fe 3+ -chelators (Ryan et al, 2001;Dakora and Phillips, 2002) are released, chelated Fe 3+ is reduced to Fe 2+ by the action of a membrane-bound Fe 3+ chelate reductase, and then Fe 2+ is transported into cells by a Fe-regulated transporter (Waters et al, 2002;Connolly et al, 2003). To support all these processes directly connected with the enhancement of Fe uptake, a supply of ATP as well as of 5 reducing agents such as NAD(P)H is essential (Zocchi, 2007).…”

Section: Introductionmentioning

confidence: 99%

Iron deficiency induces changes in riboflavin secretion and the mitochondrial electron transport chain in hairy roots of Hyoscyamus albus

Higa

Mori

Kitamura

2010

Journal of Plant Physiology

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Authorship note: AH and YM have equal contribution. 3 SummaryHyoscyamus albus hairy roots secrete riboflavin under Fe-deficient conditions. To determine whether this secretion was linked to an enhancement of respiration, both riboflavin secretion and the reduction of 2,3,5-triphenyltetrazolium (TTC), as a measure of respiration activity, were determined in hairy roots cultured under Fe-deficient and Fe-replete conditions, with or without aeration. Appreciable TTC-reducing activity was detected at the root tips, at the bases of lateral roots and in internal tissues, notably the vascular system. TTC-reducing activity increased under Fe deficiency and this increase occurred in concert with riboflavin secretion and was more apparent under aeration. Riboflavin secretion was not apparent under Fe-replete conditions.In order to examine which elements of the mitochondrial electron transport chain (mtETC) might be involved, the effects of the respiratory inhibitors, barbiturate, dicoumarol, malonic acid, antimycin, KCN and salicylhydroxamic acid (SHAM) were investigated. Under Fe-deficient conditions, malonic acid affected neither root growth, TTC-reducing activity nor riboflavin secretion, whereas barbiturate and SHAM inhibited only root growth and TTC-reducing activity, respectively, and the other compounds variously inhibited growth and TTC-reducing activity.Riboflavin secretion was decreased, in concert with TTC-reducing activity, by dicoumarol, antimycin and KCN, but not by SHAM. In Fe-replete roots, all inhibitors which reduced riboflavin secretion in Fe-deficient roots showed somewhat different effects: notably, antimycin and KCN did not significantly inhibit TTC-reducing activity and the inhibition by dicoumarol was much weaker in Fe-replete roots. Combined treatment with KCN and SHAM also revealed that Fe-deficient and Fe-replete roots reduced TTC in different ways. A decrease in the Fe content of mitochondria in Fe-deficient roots was confirmed. Overall, the results suggest that, under conditions of Fe deficiency in H. albus hairy roots, the alternative NAD(P)H dehydrogenases, complex III and complex IV, but not the alternative oxidase, are actively involved both in respiration and in riboflavin secretion.4

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“…One of the major mechanisms that plants have evolved to overcome low-P availability is to maximize the ability of the roots to acquire and absorb P from the soil. Plants can mobilize P through the exudation of organic acids, acid phosphatases, and ribonucleases, resulting in enhanced P availability and uptake (Hinsinger, 2001;Ryan et al, 2001;Dakora and Phillips, 2002;Hammond and White, 2008;Ma et al, 2009;Pang et al, 2009). Another strategy to cope with low-P availability is to increase the soil volume accessed by root systems by forming mycorrhizal symbioses Smith and Smith, 2012;Rai et al, 2013).…”

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confidence: 99%

Duplicate and Conquer: Multiple Homologs ofPHOSPHORUS-STARVATION TOLERANCE1Enhance Phosphorus Acquisition and Sorghum Performance on Low-Phosphorus Soils

et al. 2014

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Low soil phosphorus (P) availability is a major constraint for crop production in tropical regions. The rice (Oryza sativa) protein kinase, PHOSPHORUS-STARVATION TOLERANCE1 (OsPSTOL1), was previously shown to enhance P acquisition and grain yield in rice under P deficiency. We investigated the role of homologs of OsPSTOL1 in sorghum (Sorghum bicolor) performance under low P. Association mapping was undertaken in two sorghum association panels phenotyped for P uptake, root system morphology and architecture in hydroponics and grain yield and biomass accumulation under low-P conditions, in Brazil and/or in Mali. Root length and root surface area were positively correlated with grain yield under low P in the soil, emphasizing the importance of P acquisition efficiency in sorghum adaptation to low-P availability. SbPSTOL1 alleles reducing root diameter were associated with enhanced P uptake under low P in hydroponics, whereas Sb03g006765 and Sb03g0031680 alleles increasing root surface area also increased grain yield in a low-P soil. SbPSTOL1 genes colocalized with quantitative trait loci for traits underlying root morphology and dry weight accumulation under low P via linkage mapping. Consistent allelic effects for enhanced sorghum performance under low P between association panels, including enhanced grain yield under low P in the soil in Brazil, point toward a relatively stable role for Sb03g006765 across genetic backgrounds and environmental conditions. This study indicates that multiple SbPSTOL1 genes have a more general role in the root system, not only enhancing root morphology traits but also changing root system architecture, which leads to grain yield gain under low-P availability in the soil.

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Root exudates as mediators of mineral acquisition in low-nutrient environments

Cited by 554 publications

References 79 publications

Biomass ashes and their phosphorus fertilizing effect on different crops

Biomass ashes and their phosphorus fertilizing effect on different crops

Iron deficiency induces changes in riboflavin secretion and the mitochondrial electron transport chain in hairy roots of Hyoscyamus albus

Duplicate and Conquer: Multiple Homologs ofPHOSPHORUS-STARVATION TOLERANCE1Enhance Phosphorus Acquisition and Sorghum Performance on Low-Phosphorus Soils

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