Distribution of Nicotianamine, a Presumed Symplast Iron Transporter, in Different Organs of Sunflower and of a Tomato Wild Type and Its Mutant chloronerva

Stephan, Udo W.; Scholz, Günter; Rudolph, Armin

doi:10.1016/s0015-3796(11)80154-x

Cited by 27 publications

(12 citation statements)

References 12 publications

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“…In the cotyledons and in the hypocotyl the NA concentrations show a transient maximum well corresponding to the period of the highest metal translocation rates. The high NA concentrations in the seedling organs show an analogy to the findings of Stephan et al (1990) that the highest values in sunflower could be measured in the youngest still actively growing tissues. It has been demonstrated that the translocation of Fe via the phloem in the NA-free tomato mutant chloronerva occurred only after application of exogenous NA (Scholz, 1989).…”

Section: Discussionsupporting

confidence: 81%

Phloem translocation of Fe, Cu, Mn, and Zn in Ricinus seedlings in relation to the concentrations of nicotianamine, an endogenous chelator of divalent metal ions, in different seedling parts

1994

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During the first 8 days of germination the Ricinus seedling is supplied with all nutrients by the endosperm via phloem transport. In 4-to 8-days-old seedlings the concentrations and contents of Fe, Cu, Mn and Zn, and nicotianamine (NA) in the endosperm, cotyledons, hypocotyl and roots were estimated. From the data obtained translocation rates and flow profiles for the metals were established. The main sink for Fe, Mn and Zn were the cotyledons whereas Cu was mainly imported into the hypocotyl. Maximum flow rates occurred between days 5 and 7, for Zn between days 6 and 8.The time kinetics of NA and divalent metal ion concentrations and contents are interpreted as co-transport. The role of NA as transport vehicle of micronutrients in the sieve tubes is discussed.Abbreviations: NA, nicotianamine

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Section: Discussionsupporting

confidence: 81%

Phloem translocation of Fe, Cu, Mn, and Zn in Ricinus seedlings in relation to the concentrations of nicotianamine, an endogenous chelator of divalent metal ions, in different seedling parts

1994

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“…This observation is in agreement with our previous findings that NAS activity was detected in both shoots and roots of Fe sufficient Strategy I plants such as tobacco and tomato (Higuchi et al 1996b). This finding is also consistent with the fact that the concentrations of NA in shoots and roots are in the same range in tomato plants (Stephan et al 1990) and tobacco plants (Noma and Noguchi 1976).…”

Section: Shoot Rootsupporting

confidence: 90%

Cloning of nicotianamine synthase genes fromArabidopsis thaliana

Suzuki

Higuchi

Nakanishi

et al. 1999

Soil Science and Plant Nutrition

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“…NA is probably ubiquitous among plants (Prochb.zka & Scholz 1984, Rudolph et al 1985. In young growing tissues concentrations of several hundred l~ NA were reported (Stephan et al 1990, 1994.…”

Section: Introductionmentioning

confidence: 99%

The nicotianamine molecule is made-to-measure for complexation of metal micronutrients in plants

et al. 1996

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The non-proteinogenic amino acid nicotianamine (NA) is ubiquitous among plants. In meristematic tissues it reaches concentrations of about 400/lmol (g fresh weight)-i. NA forms complexes, among others, with the metal micronutrients (MN) copper, zinc, iron and manganese (log KMeNA 18.6-8.8). Calculations of the dissociation curves of the metal-NA complexes based on the complex formation constants and on the acid dissociation constants of NA revealed their stability at the neutral or weak alkaline pH of cytoplasm and sieve tube sap. For the Mn-NA complex, dissociation begins at about pH 6.5, for all others dissociation occurs at more acid pHs. Thus, metal-NA complexes could theoretically persist also in the apoplasm and in xylem sap. The octanol water partition coefficient of NA is about 1 and those of its metal complexes arc in the range of 0.3-0.4. The reason for this shift is perhaps the negative charge of the complexes. The higher lipophilicity of the free NA indicates that the NA supply to sites of requirement is faster than the removal of the complexes as long as membranes are an integral part of the transport paths. Changing phloem transport rates of MN-NA complexes by manipulation of the cotyledon apoplasm of Ricinus communis L. suggest a competition of MN for NA at the site(s) of phloem loading. Thus, NA could control MN transport via phloem including recirculation.

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Distribution of Nicotianamine, a Presumed Symplast Iron Transporter, in Different Organs of Sunflower and of a Tomato Wild Type and Its Mutant chloronerva

Cited by 27 publications

References 12 publications

Phloem translocation of Fe, Cu, Mn, and Zn in Ricinus seedlings in relation to the concentrations of nicotianamine, an endogenous chelator of divalent metal ions, in different seedling parts

Phloem translocation of Fe, Cu, Mn, and Zn in Ricinus seedlings in relation to the concentrations of nicotianamine, an endogenous chelator of divalent metal ions, in different seedling parts

Cloning of nicotianamine synthase genes fromArabidopsis thaliana

The nicotianamine molecule is made-to-measure for complexation of metal micronutrients in plants

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