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Solute balance of a maize (Zea mays L.) source leaf as affected by salt treatment with special emphasis on phloem retranslocation and ion leaching

Solute balance of a maize (Zea mays L.) source leaf as affected by salt treatment with special emphasis on phloem retranslocation and ion leaching

Authors :
Melanie Hussmann
Gertrud Lohaus
Kerstin Pennewiss
Heike Schneider
Jian‐Jun Zhu
Burkhard Sattelmacher
Source :
Journal of Experimental Botany. 51:1721-1732
Publication Year :
2000
Publisher :
Oxford University Press (OUP), 2000.

Abstract

Strategies for avoiding ion accumulation in leaves of plants grown at high concentration of NaCl (100 mol m(-3)) in the rooting media, i.e. retranslocation via the phloem and leaching from the leaf surface, were quantified for fully developed leaves of maize plants cultivated hydroponically with or without salt, and with or without sprinkling (to induce leaching). Phloem sap, apoplastic fluid, xylem sap, solutes from leaf and root tissues, and the leachate were analysed for carbohydrates, amino acids, malate, and inorganic ions. In spite of a reduced growth rate Na(+) and Cl(-) concentrations in the leaf apoplast remained relatively low (about 4-5 mol m(-3)) under salt treatment. Concentrations of Na(+) and Cl(-) in the phloem sap of salt-treated maize did not exceed 12 and 32 mol m(-3), respectively, and thus remained lower than described for other species. However, phloem transport rates of these ions were higher than reported for other species. The relatively high translocation rate of ions found in maize may be due to the higher carbon translocation rate observed for C(4) plants as opposed to C(3) plants. Approximately 13-36% of the Na(+) and Cl(-) imported into the leaves through the xylem were exported by the phloem. It is concluded that phloem transport plays an important role in controlling the NaCl content of the leaf in maize. Surprisingly, leaching by artificial rain did not affect plant growth. Ion concentrations in the leachate were lower than reported for other plants but increased with NaCl treatment.

Details

ISSN :
14602431 and 00220957
Volume :
51
Database :
OpenAIRE
Journal :
Journal of Experimental Botany
Accession number :
edsair.doi.dedup.....03465bc78f0dc17dc650a2ba9f9ba94b
Full Text :
https://doi.org/10.1093/jexbot/51.351.1721