title: Is callose a barrier for lead ions entering Lemna minor L. root cells?
abstract: Plants have developed a range of strategies for resisting environmental stresses. One of the most common is the synthesis and deposition of callose, which functions as a barrier against stress factor penetration. The aim of our study was to examine whether callose forms an efficient barrier against Pb penetration in the roots of Lemna minor L. exposed to this metal. The obtained results showed that Pb induced callose synthesis in L. minor roots, but it was not deposited regularly in all tissues and cells. Callose occurred mainly in the protoderm and in the centre of the root tip (procambial central cylinder). Moreover, continuous callose bands, which could form an efficient barrier for Pb penetration, were formed only in the newly formed and anticlinal cell walls (CWs); while in other CWs, callose formed only small clusters or incomplete bands. Such an arrangement of callose within root CWs inefficiently protected the protoplast from Pb penetration. As a result, Pb was commonly present inside the root cells. In the light of the results, the barrier role of callose against metal ion penetration appears to be less obvious than previously believed. It was indicated that induction of callose synthesis is not enough for a successful blockade of the stress factor penetration. Furthermore, it would appear that the pattern of callose distribution has an important role in this defence strategy.
authors: Laboratory of Electron and Confocal Microscopy, Faculty of Biology, Adam Mickiewicz University, 89 Umultowska Street, 61-614, Poznań, Poland. sas@amu.edu.pl
authors: Sławomir
authors: S
authors: Samardakiewicz
authors: Magdalena
authors: M
authors: Krzesłowska
authors: Henryk
authors: H
authors: Bilski
authors: Rafał
authors: R
authors: Bartosiewicz
authors: Adam
authors: A
authors: Woźny
references: Trends Plant Sci. 2004 Apr;9(4):203-9
references: 15063871
references: Curr Opin Plant Biol. 2009 Aug;12(4):406-13
references: 19616468
references: Ecotoxicol Environ Saf. 2007 Nov;68(3):343-50
references: 17416417
references: Semin Cell Dev Biol. 2009 Dec;20(9):1074-81
references: 19501662
references: Plant Signal Behav. 2007 Sep;2(5):404-7
references: 19704615
references: Plant Physiol. 2000 Nov;124(3):991-1006
references: 11080277
references: Environ Pollut. 2010 Jan;158(1):325-38
references: 19647914
references: Protoplasma. 2011 Jan;248(1):117-30
references: 21116665
references: Sci Total Environ. 2008 Aug 1;400(1-3):356-68
references: 18657304
references: Curr Opin Biotechnol. 2005 Apr;16(2):123-32
references: 15831376
references: Mol Plant Microbe Interact. 2011 Feb;24(2):183-93
references: 20955078
references: Protoplasma. 2003 Mar;220(3-4):219-25
references: 12664286
references: Proc Natl Acad Sci U S A. 2005 Aug 23;102(34):12089-94
references: 16103368
references: Environ Res. 1990 Jun;52(1):7-22
references: 2190824
references: Plant Physiol. 1979 Jun;63(6):1170-4
references: 16660877
references: Curr Opin Microbiol. 2005 Aug;8(4):399-404
references: 15996507