Abstract : Hydroxamate siderophores have been found to alleviate Al toxicity in bacteria. In Poaceae plant cyc
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Abstract : Hydroxamate siderophores have been found to alleviate Al toxicity in bacteria. In Poaceae plant cyclic Hx, like DIMBOA and its derivatives have mostly been studied in relation to either defence against insects or allelopathy. In this study the influence of Al concentration of these benzoxazinoids (Bx)in root tip,and whole root of Zea maysL. varieties differing in Al resistance was analized by HPLC-Ms. Aluminium resistant maize variety Sikuani maintained considerabily higher Bx levels in root tips than the Al sensitive Bakero. In vitro binding of Al to DIMBOA was shown by fluorescence quenching. Addition of DIMBOA to Al-containing nutrient solution protected the sensitive maize against Al toxicity as shown by bioassays using callose and haematoxylin satining of root tips as stress indicators. This is the first study showing that Bx can detoxify Al in solution. Tissue analysis data provide first, circumstantial, supportfor role of Bx in defence against Al toxicity also in planta.- Slides
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