Plant Biol (Stuttg) 2004; 6(5): 578-589
DOI: 10.1055/s-2004-821089
Original Paper

Georg Thieme Verlag Stuttgart KG · New York

Specific Intra-Tissue Responses to Manganese in the Floating Lamina of Trapa natans L.

C. Baldisserotto1 , L. Ferroni1 , V. Medici1 , A. Pagnoni2 , M. Pellizzari1 , M. P. Fasulo1 , F. Fagioli2 , A. Bonora1 , S. Pancaldi1
  • 1Dipartimento delle Risorse Naturali e Culturali, University of Ferrara, C.so Porta Mare, 2, 44100 Ferrara, Italy
  • 2Laboratory of Atomic Spectroscopy, Department of Chemistry, University of Ferrara, via L. Borsari, 46, 44100 Ferrara, Italy
Further Information

Publication History

Publication Date:
06 August 2004 (online)

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Abstract

Plant tolerance to heavy metals requires morpho-physiological mechanisms that are still poorly understood, especially in hydrophytes. This study focuses on the young floating lamina of the rhyzophyte Trapa natans exposed for 10 d to 130 µM Mn. The lamina has the ability to bioaccumulate Mn (> 3000 µg g-1). X-ray microanalysis of Mn cellular distribution revealed accumulation in the upper epidermis, in the first palisade layer, and in the idioblasts of the spongy tissue, which were shown with electron microscopy to contain osmiophilic vacuolar deposits, also observed to a minor extent in the control leaves. On the basis of biochemical and histochemical tests, these deposits were attributed to phenolic compounds that were probably able to chelate Mn. Net photosynthesis, photosynthetic pigments, room temperature microspectrofluorimetric analyses, and ultrastructural studies of plastids were performed to evaluate the status of the photosynthetic apparatus. A greater development of thylakoid membranes was observed in plastids of the second palisade and spongy tissue, which, however, did not accumulate Mn. Only the spongy tissue experienced inadequate assembly of PS II, but this did not significantly influence the photosynthetic yield of the whole lamina. It was concluded that T. natans can optimise productivity in the presence of Mn by means of specific intra-tissue responses within the framework of the floating lamina.

References

M. P. Fasulo

Dipartimento delle Risorse Naturali e Culturali
University of Ferrara

Corso Porta Mare, 2

44100 Ferrara

Italy

Email: fsm@dns.unife.it

Section Editor: J. T. M. Elzenga