Exchange between phloem and xylem during long distance transport of glutathione in spruce trees [<i>Picea abies</i>[Karst.] L.)

Schneider, Andrea; Schatten, Theodor; Rennenberg, Heinz

doi:10.1093/jxb/45.4.457

Cited by 60 publications

(55 citation statements)

References 19 publications

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“…It might represent part of the N storage pool mobilized during growth of current year's needles (Nambiar & Fife, 1991 ;Flaig & Mohr, 1992 ;Gezelius & Na$ sholm, 1993). During initial development of the current year's needles Arg, the predominant TSNN compound, might originate from three sources : (1) phloem transport of Arg from the previous year's needles, as previously also observed for glutathione in spruce trees (Schneider et al, 1994 ;Blaschke et al, 1996), (2) transformation of Gln allocated to the current year's needles in xylem and phloem, and (3) assimilation of inorganic N taken up from the atmosphere. Since trees at the field site studied are exposed to a high atmospheric N input (Go$ ttlein & Kreutzer, 1991) uptake of NH y and NO x might be significant (Brumme et al, 1992 ;Nussbaum et al, 1993 ;Pearson & Stewart, 1993 ;Weber et al, 1995 ;Muller et al, 1996) and Arg accumulation in the needles might indicate excess N supply (Na$ sholm & Ericson, 1989).…”

Section: Arginine Is the Most Important Tsnn Compound In The Needlesmentioning

confidence: 55%

“…Nitrogen compounds required for growth of developing tissues can be taken out of this pool, and remaining N might serve as an indicator of the N status of the tree, regulating N uptake (Cooper & Clarkson, 1989 ;Larsson et al, 1991 ;Touraine, Clarkson & Muller, 1994). A prerequisite for such a circulation within the tree is the exchange of TSNN compounds between xylem and phloem as already observed for Gln in Populus deltoides (Dickson, Vogelmann & Larson, 1985) and for glutathione in spruce (Schneider et al, 1994). Various studies have been performed to examine the influence of phloem-translocated amino acids on nitrate uptake by roots (Cooper & Clarkson, 1989 ;Muller & Touraine, 1992 ;Muller, Tillard & Touraine, 1995).…”

Section: A Cycling Pool Of Amino Acids Might Be Involved In the Regulmentioning

confidence: 99%

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Soluble N compounds in trees exposed to high loads of N: a comparison between the roots of Norway spruce (Picea abies) and beech (Fagus sylvatica) trees grown under field conditions

et al. 1998

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During the growing session of 1995, the total soluble non‐protein nitrogen (TSNN) composition and contents of mycorrhizal fine roots, xylem sap and phloem exudates of roots from a coniferous (Picea abies L.(Karst)) and a deciduous (Fagus sylvatica L.) tree species were analysed at a field site (‘Höglwald’, Germany) exposed to high loads of N. In April, TSNN in fine roots of spruce and beech trees amounted to 16 μmol N g−1 f. wt and 23·3 μmol N g−1 f. wt, respectively. It decreased to 9·2 μmol N g−1 f. wt and 18·1 μmol N g−1 f. wt, respectively, after bud break in June. The seasonal maximum of TSNN in fine roots of spruce was observed in July (32·7 μmol N g−1 f. wt) followed by a decline of c. 30% until the end of the growing season in September. TSNN in fine roots of beech trees showed a further decline between June and July, when its seasonal minimum was determined (15·6 μmol N g−1 f. wt), and increased to c. 29 μmol N g−1 f. wt until September. In spruce roots Gln and Arg were the most abundant TSNN compounds during the entire growing season. In roots of beech Asn played an important role alongside Gln and Arg, especially in April, when it was the most abundant TSNN compound. Other proteinogenic and non‐proteinogenic N compounds comprised c. 20–30% of TSNN. Nitrate made up <1%, and ammonium <7% of TSNN in the fine roots of both species. In April, TSNN in the xylem sap of roots of spruce and beech trees amounted to 3·4 and 8·6 μmol N ml−1, respectively. In roots of spruce trees xylem sap TSNN increased after bud break up to 12·7 μmol N ml−1 in July. At the end of the growing season TSNN had declined again to 3·9 μmol N ml−1. TSNN in the root xylem sap of beech trees decreased after bud break until July (2·4 μmol N ml−1 in July) followed by a slight increase until September (2·9 μmol N ml−1). Arg, Gln and Asp were the most abundant TSNN compounds in the xylem sap of spruce trees contributing together c. 90% to TSNN. The same TSNN compounds prevailed in the root xylem sap of beech trees in April and July, whereas in June and September Asp was replaced by Asn comprising 57% of TSNN in June. In addition to the N compounds mentioned above, a number of other proteinogenic and non‐proteinogenic amino compounds were found in root xylem sap of both species. In either species, nitrate and ammonium were present in small amounts, contributing <1% and <4% to TSNN, respectively. Apparently, inorganic N taken up by the mycorrhizal roots is mainly assimilated in root tissues or by the mycorrhiza and N uptake by the roots is largely adapted to the assimilatory capacity of this organ. In phloem exudates of spruce roots, TSNN amounted to 10·7 μmol N g−1 f. wt in April, increased in June to 23·4 μmol N g−1 f. wt and decreased again until September to a seasonal minimum of 4·8 μmol N g−1 f. wt. In contrast to spruce, TSNN content in phloem exudates of beech roots showed a seasonal maximum (c. 20 μmol N g−1 f. wt) in April with a subsequent decrease in June after bud break (c. 2 μmol N g−1 f. wt). A fourfold increase in July was foll...

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Section: Arginine Is the Most Important Tsnn Compound In The Needlesmentioning

confidence: 55%

Section: A Cycling Pool Of Amino Acids Might Be Involved In the Regulmentioning

confidence: 99%

Soluble N compounds in trees exposed to high loads of N: a comparison between the roots of Norway spruce (Picea abies) and beech (Fagus sylvatica) trees grown under field conditions

et al. 1998

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“…Both S0,2p and GSH are translocated within the sieve sap (Rennenberg et al, 1979;Bonas et al, 1982;Rennenberg, 1982;Schneider et al, 1994), so both of them are, a priori, good candidates for this role. However, the analyses of phloem exudates made in canola (Table 111) strongly support the hypothesis that GSH is the sought molecule because its concentration in phloem sap dropped by more than 60% within the 1st d after 50,'-withdrawal from the external solution, whereas the concentration of S0,'-failed to change.…”

Section: Discussionmentioning

confidence: 99%

“…1 1 1, 1996berg, 1991. Reduced S molecules are translocated in the phloem (Rennenberg et al, 1979;Bonas et al, 1982;Rennenberg, 1982;Schneider et al, 1994), so this may be the route whereby S demand information is conveyed from shoots to roots.…”

mentioning

confidence: 99%

Demand-Driven Control of Root ATP Sulfurylase Activity and SO42- Uptake in Intact Canola (The Role of Phloem-Translocated Glutathione)

1996

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The activity of ATP sulfurylase extracted from roots of intact canola (Brassica napus 1. cv Drakkar) increased after withdrawal of the S source from the nutrient solution and declined after refeeding S0,'-to S-starved plants. The rate of S0,'-uptake by the roots was similarly influenced. ldentical responses were obtained in SO,'--fed roots when one-half of the root system was starved for S. S is predominantly available to higher plants as S0,'-taken up from soil by the roots. The rate of S uptake by plant roots, especially those of crop species, which have been bred for their fast growth capacity and high harvest potential, is controlled by regulatory processes that operate in such a way that the needs of the whole organism are matched by rates of S uptake. A good illustration of this behavior is provided by the severalfold enhancement of S0: -uptake observed in plants previously deprived of S for periods of a few hours to a few days (

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“…Therefore, long-distance transport of sulphur from the leaves to the roots was analysed in the present study. Since the tripeptide glutathione is the predominant long-distance transport form of reduced sulphur not only in herbaceous plants (Rennenberg 1995), but also in tree species (Schupp et al 1992;Schneider et al 1994; including oak (Fig. 4), radiolabelled glutathione was fed to individual oak leaves and the distribution of radiolabel within the plants was studied.…”

Section: Discussionmentioning

confidence: 99%

Interactive effects of elevated atmospheric CO₂, mycorrhization and drought on long‐distance transport of reduced sulphur in young pedunculate oak trees (Quercus robur L.)

Schulte

Herschbach

Rennenberg

1998

Plant Cell & Environment

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Pedunculate oak (Quercus robur L.) was germinated and grown under nutrient non-limiting conditions for a total of 10-15 weeks at ambient CO 2 concentration and 1100 µmol mol -1 CO 2 either in the presence or the absence of the mycorrhizal fungus Laccaria laccata. Half of the oak trees of these treatments were exposed to drought during final growth by suspending the water supply for 21 d. Mycorrhization and elevated atmospheric CO 2 each enhanced total plant biomass per tree. Whereas additional biomass accumulation of trees grown under elevated CO 2 was mainly attributed to increased growth of lateral roots, mycorrhization promoted shoot growth. Water deficiency reduced biomass accumulation without affecting relative water content, but this effect was more pronounced in mycorrhizal as compared to non-mycorrhizal trees. Elevated CO 2 partially prevented the development of drought stress, as indicated by leaf water potential, but did not counteract the negative effects of water deficiency on growth during the time studied. Enhanced biomass accumulation requires adaption in protein synthesis and, as a consequence, enhanced allocation of reduced sulphur produced in the leaves to growing tissues. Therefore, allocation of reduced sulphur from oak leaves was studied by flapfeeding radiolabelled GSH, the main long-distance transport form of reduced sulphur, to mature oak leaves. Export of radiolabel proceeded almost exclusively in basipetal direction to the roots. The rate of export of radioactivity out of the fed leaves was significantly enhanced under elevated CO 2 , irrespective of mycorrhization. A higher proportion of the exported GSH was transported to the roots than to basipetal stem sections under elevated CO 2 as compared to ambient CO 2 . Mycorrhization did not affect 35 S export out of the fed leaves, but the distribution of radiolabel between stem and roots was altered in preference of the stem. Trees exposed to drought did not show appreciable export of the 35 S radioactivity fed to the leaves when grown under ambient CO 2 . Apparently, drought inhibited basipetal transport of reduced sulphur at the level of phloem loading and/or phloem transport. Elevated CO 2 seemed to counteract this effect of drought stress to some extent, since higher leaf water potentials and improved 35 S export out of the fed leaves was observed in oak trees exposed to drought and elevated CO 2 as compared to trees exposed to drought and ambient CO 2 .

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Exchange between phloem and xylem during long distance transport of glutathione in spruce trees [Picea abies[Karst.] L.)

Cited by 60 publications

References 19 publications

Soluble N compounds in trees exposed to high loads of N: a comparison between the roots of Norway spruce (Picea abies) and beech (Fagus sylvatica) trees grown under field conditions

Soluble N compounds in trees exposed to high loads of N: a comparison between the roots of Norway spruce (Picea abies) and beech (Fagus sylvatica) trees grown under field conditions

Demand-Driven Control of Root ATP Sulfurylase Activity and SO42- Uptake in Intact Canola (The Role of Phloem-Translocated Glutathione)

Interactive effects of elevated atmospheric CO₂, mycorrhization and drought on long‐distance transport of reduced sulphur in young pedunculate oak trees (Quercus robur L.)

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Exchange between phloem and xylem during long distance transport of glutathione in spruce trees [Picea abies[Karst.] L.)

Cited by 60 publications

References 19 publications

Soluble N compounds in trees exposed to high loads of N: a comparison between the roots of Norway spruce (Picea abies) and beech (Fagus sylvatica) trees grown under field conditions

Soluble N compounds in trees exposed to high loads of N: a comparison between the roots of Norway spruce (Picea abies) and beech (Fagus sylvatica) trees grown under field conditions

Demand-Driven Control of Root ATP Sulfurylase Activity and SO42- Uptake in Intact Canola (The Role of Phloem-Translocated Glutathione)

Interactive effects of elevated atmospheric CO2, mycorrhization and drought on long‐distance transport of reduced sulphur in young pedunculate oak trees (Quercus robur L.)

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Interactive effects of elevated atmospheric CO₂, mycorrhization and drought on long‐distance transport of reduced sulphur in young pedunculate oak trees (Quercus robur L.)