title: Structural changes in Medicago truncatularoot nodules caused by short-term aluminum stress.
abstract: Aluminum in the form of Al3+is one of the most toxic heavy metal pollutants in nature and its effects are primarily root-related. Roots ofMedicago truncatulaexposed to 50 μM of AlCl3for 2 h and 24 h were examined by light and electron microscopy. Changes in the appearance of the host cells, infection threads and bacteroidal tissue occurred during the first 2 h of Al stress. Microscopic observations showed that aluminum: (1) induced thickening of plant cell and infection threads (ITs) walls, (2) stimulated IT enlargement, (3) caused disturbances in bacterial release from the ITs, (4) modified cell vacuolation and induced synthesis of granular material and its deposition in the cytoplasm, (5) and caused structural alterations of organella and bacteroids.
authors.affiliation: University of Life Sciences in Warsaw, Warsaw, Poland.
authors.forename: Marzena
authors.initials: M
authors.lastname: Sujkowska-Rybkowska
authors.forename: Wojciech
authors.initials: W
authors.lastname: Borucki
authors.forename: Ewa
authors.initials: E
authors.lastname: Znojek
keywords: Aluminum toxicity; Medicago truncatula; Nodule; Rhizobia; Symbiotic nitrogen fixation