Changes in the xylem exudate composition of poplar (Populus tremula x P. alba)--dependent on the nitrogen and potassium supply

Siebrecht, S.; Tischner, Rudolf

doi:10.1093/jxb/50.341.1797

Cited by 29 publications

(40 citation statements)

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“…2), the other major transport amino acid, Asn, was barely detected in xylem extracts (data not shown). This is in line with reports that Gln and Asn comprise nearly 100% of Populus xylem sap amino acids and occur in a Gln-to-Asn ratio of 3:1 to 10:1 (Dickson, 1979;Schneider et al, 1994;Siebrecht and Tischner, 1999). Thus, it would appear that nitrate and Asn accumulated in YL but that nitrate was much more actively assimilated in older leaves (EL).…”

Section: Malate Homeostasis and Nitrogen Assimilationsupporting

confidence: 91%

“…In Populus, nitrogen taken up by the roots is transported in the xylem to shoot tissues primarily in the nitrate-and amino-nitrogen forms (Siebrecht and Tischner, 1999;Black et al, 2002). The transported nitrate is then reduced and assimilated, primarily in young leaves (LPI 3), where nitrate reductase activity is most highly concentrated (Black et al, 2002).…”

Section: Malate Homeostasis and Nitrogen Assimilationmentioning

confidence: 99%

“…Amino acids typically comprise more than 50% of xylem nitrogen in Populus (Siebrecht and Tischner, 1999), and their delivery in the transpiration stream probably contributed heavily to leaf nitrogen status. Asn, with its two amino groups and very low carbonto-nitrogen ratio, was at its highest level in YL.…”

Section: Malate Homeostasis and Nitrogen Assimilationmentioning

confidence: 99%

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Metabolic Profiling of the Sink-to-Source Transition in Developing Leaves of Quaking Aspen

et al. 2004

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Profiles of small polar metabolites from aspen (Populus tremuloides Michx.) leaves spanning the sink-to-source transition zone were compared. Approximately 25% of 250 to 300 routinely resolved peaks were identified, with carbohydrates, organic acids, and amino acids being most abundant. Two-thirds of identified metabolites exhibited greater than 4-fold changes in abundance during leaf ontogeny. In the context of photosynthetic and respiratory measurements, profile data yielded information consistent with expected developmental trends in carbon-heterotrophic and carbon-autotrophic metabolism. Suc concentration increased throughout leaf expansion, while hexose sugar concentrations peaked at mid-expansion and decreased sharply thereafter. Amino acid contents generally decreased during leaf expansion, but an early increase in Phe and a later one in Gly and Ser reflected growing commitments to secondary metabolism and photorespiration, respectively. The assimilation of nitrate and utilization of stored Asn appeared to be marked by sequential changes in malate concentration and Asn transaminase activity. Principal component and hierarchical clustering analysis facilitated the grouping of cell wall maturation (pectins, hemicelluloses, and oxalate) and membrane biogenesis markers in relation to developmental changes in carbon and nitrogen assimilation. Metabolite profiling will facilitate investigation of nitrogen use and cellular development in Populus sp. varying widely in their growth and pattern of carbon allocation during sink-to-source development and in response to stress.Quaking aspen (Populus tremuloides Michx.) is an ecological keystone species, an important component of the wood products industry, and a useful experimental model system for the study of woody plant development (Bradshaw et al., 2000). We are interested in using metabolic profiling to characterize the sink-to-source transition in developing aspen leaves. The approach is expected to provide a basis for more extended studies analyzing the effects of various carbon sinks on aspen development and growth. An illustrative example is the regulation of phenolic sinks in leaves of aspen and close relatives in the genera Populus and Salix (Orians and Fritz, 1995;Lindroth and Hwang, 1996;Kao et al., 2002). Phenolic deposition is very characteristic of these species, exhibits wide genetic variation, can begin early during aspen leaf expansion (Kleiner et al., 1999;Kao et al., 2002), and can reach levels that negatively affect aspen stem and branch growth (Lindroth and Hwang, 1996). The allocation of metabolic carbon into such sinks is influenced by plant nutrient status and photosynthesis rate (Bryant et al., 1983;Hemming and Lindroth, 1999;Mansfield et al., 1999) and in young leaves, therefore, may be linked to metabolic development.Metabolic profiling of plants is generally geared toward the extraction of a broad spectrum of biochemical information from multiple sample types by relatively direct analytical means (for review, see Fiehn and Weckwerth, 200...

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Section: Malate Homeostasis and Nitrogen Assimilationsupporting

confidence: 91%

Section: Malate Homeostasis and Nitrogen Assimilationmentioning

confidence: 99%

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Metabolic Profiling of the Sink-to-Source Transition in Developing Leaves of Quaking Aspen

et al. 2004

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“…The comparison revealed that all tested species and genotypes accumulated Al in the shoot, thus no qualitative differences were found. In a recent study comparing Al tolerance and Al accumulation of three Fagopyrum species (F. esculentum, F. tataricum, F. homotropicum) reference [27] also concluded that Al accumulation is a conserved trait in Fagopyrum. However, there were significant quantitative differences in Al accumulation capability.…”

Section: Discussionmentioning

confidence: 99%

“…The xylem-sap Al concentration was chosen as the primary parameter for the comparison of the genotypes for Al accumulation capacity. The xylem sap was sampled after only 0.5 h, because various studies showed that only shortly after cutting of the shoot representative data on the in vivo xylem-sap composition can be assessed [27]. Moreover, the same technique has been used for the characterization of heavy metal hyper-accumulation.…”

Section: Discussionmentioning

confidence: 99%

Differences in Aluminium Accumulation and Resistance between Genotypes of the Genus Fagopyrum

Klug¹,

Kirchner

Horst

2015

Agronomy

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Aluminium (Al) toxicity is a major factor reducing crop productivity worldwide. There is a broad variation in intra-and inter-specific Al resistance. Whereas the Al resistance mechanisms have generally been well explored in Al-excluding plant species, Al resistance through Al accumulation and Al tolerance is not yet well understood. Therefore, a set of 94 genotypes from three Fagopyrum species with special emphasis on F. esculentum Moench were screened, with the objective of identifying genotypes with greatly differing Al accumulation capacity. The genotypes were grown in Al-enriched peat-based substrate for 21 days. Based on the Al concentration of the xylem sap, which varied by a factor of five, only quantitative but not qualitative genotypic differences in Al accumulation could be identified. Aluminium and citrate and Al and Fe concentrations in the xylem sap were positively correlated suggesting that Fe and Al are loaded into and transported in the xylem through related mechanisms. In a nutrient solution experiment using six selected F. esculentum genotypes differing in Al and citrate concentrations in the xylem sap the significant correlation between Al and iron transport in the xylem could be confirmed. Inhibition of root elongation by Al was highly significantly correlated with root oxalate-exudation and leaf Al accumulation. This suggests that Al-activated oxalate exudation and rapid transport of Al to the shoot are prerequisites for the protection of the root apoplast from Al injury and thus overall Al resistance and Al accumulation in buckwheat.

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Chloride in Soils and its Uptake and Movement within the Plant: A Review

White¹

2001

Annals of Botany

574

391

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Changes in the xylem exudate composition of poplar (Populus tremula x P. alba)--dependent on the nitrogen and potassium supply

Cited by 29 publications

References 1 publication

Metabolic Profiling of the Sink-to-Source Transition in Developing Leaves of Quaking Aspen

Metabolic Profiling of the Sink-to-Source Transition in Developing Leaves of Quaking Aspen

Differences in Aluminium Accumulation and Resistance between Genotypes of the Genus Fagopyrum

Chloride in Soils and its Uptake and Movement within the Plant: A Review

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