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The apoplast and its significance for plant mineral nutrition
Author(s) -
Sattelmacher Burkhard
Publication year - 2001
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2001.00034.x
Subject(s) - apoplast , symplast , xylem , cell wall , botany , vacuole , biology , biophysics , nutrient , water transport , middle lamella , biochemistry , cytoplasm , ecology , environmental science , water flow , environmental engineering
It has only recently become apparent that the apoplast plays a major role in a diverse range of processes, including intercellular signalling, plant–microbe interactions and both water and nutrient transport. Broadly defined, the apoplast constitutes all compartments beyond the plasmalemma – the interfibrillar and intermicellar space of the cell walls, and the xylem, including its gas‐ and water‐filled intercellular space – extending to the rhizoplane and cuticle of the outer plant surface. The physico‐chemical properties of cell walls influence plant mineral nutrition, as nutrients do not simply pass through the apoplast to the plasmalemma but can also be adsorbed or fixed to cell‐wall components. Here, current progress in understanding the significance of the apoplast in plant mineral nutrition is reviewed. The contribution of the root apoplast to short‐distance transport and nutrient uptakes is examined particularly in relation to Na + toxicity and Al 3+ tolerance. The review extends to long‐distance transport and the role of the apoplast as a habitat for microorganisms. In the leaf, the apoplast might have benefits over the vacuole as a site for short‐term nutrient storage and solute exchange with the atmosphere.ContentsSummary 167 I. Introduction 168 II. The properties of the apoplast and its implication for solute movement 1681. The middle lamella 1682. The primary wall 1683. The secondary cell wall 169 III. The root apoplast – nutrient uptake and short‐distance transport 170 IV. The apoplast as a compartment for long distance transport 174 V. The apoplast – habitat for microorganisms 175 VI. The apoplast of leaves – a compartment of storage and of reactions 1771. Transport routes in the leaf apoplast 1772. Methods of studying apoplastic solutes 1773. Solute relations in the leaf apoplast 1784. Concentration gradients in the leaf apoplast 1795. Ion relations in the leaf apoplast and symptoms of deficiency and toxicity 1796. Ion relations in the leaf apoplast – influence of nutrient supply 1807. The leaf apoplast – compartment for transient ion storage 1808. Ion fluxes between apoplast and symplast 1819. Apoplastic ion balance 18110. Leaf apoplast – interaction with the atmosphere 183 VII. Conclusions 183Acknowledgements 183References 183