Root cell patterning: a primary target for aluminium toxicity in maize.
The short-term influence (5-180 min) of 50 microM Al on cell division was investigated in root tips of two Zea mays L. varieties differing in Al-resistance. The incorporation of bromodeoxyuridine into S-phase nuclei was visualized by immunofluorescence staining using confocal laser fluorescence microscopy. In Al-sensitive plants 5 min Al exposure was enough to inhibit cell division in the proximal meristem (250-800 microm from the tip). After 10 or 30 min with Al only, a few S-phase nuclei were found in the cortical initials. By contrast, cell division was stimulated in the distal elongation zone (2.5-3.1 mm). After 180 min the protrusion of an incipient lateral root was observed in this zone. These observations suggest a fast change in cell patterning rather than a general cariotoxic effect after exposure to Al for a short time. No such changes were found in Al-resistant maize. This is the first report showing such fast Al-induced alterations in the number and the position of dividing cells in root tips. The observation that similar changes were induced by a local supply of naphthylphthalamic acid to the distal transition zone suggests that inhibition of auxin transport plays a role in the Al-induced alteration of root cell patterning.
Doncheva
Snezhanka
S
Laboratorio de Fisiología Vegetal, Facultad de Ciencias, Universidad Autónoma de Barcelona, E-08193 Bellaterra, Spain. juan.barcelo@uab.es
Amenós
Montserrat
M
Poschenrieder
Charlotte
C
Barceló
Juan
J
D000535:Aluminum / Q000633:toxicity*; D002455:Cell Division / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D018519:Meristem / Q000166:cytology / Q000187:drug effects; D018613:Microscopy, Confocal; D008940:Mitotic Index; D018517:Plant Roots / Q000166:cytology* / Q000187:drug effects; D016196:S Phase / Q000187:drug effects; D003313:Zea mays / Q000166:cytology* / Q000187:drug effects
D000535:Aluminum