Tham khảo tài liệu 'food production approaches, challenges and tasks part 14', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 236 Food Production - Approaches Challenges and Tasks The main aluminum toxicity symptom is inhibition of root elongation with simultaneous induction of P-1 3-glucan callose synthesis which is apparent alter even a short exposure time. Aluminium causes extensive root injury leading to poor ion and water uptake Barcelo Poschenrieder 2002 . One of hypothesis is that the sequence of toxicity starts with perception of aluminum by the root cap cells followed by signal transduction and a physiological response within the root meristem. However recent work has ruled out a role of the root cap and emphasizes that the root meristem is the sensitive site. Root tips have been found to be the primary site of aluminum injury and the distal part of the transition zone has been identified as the target site in maize Zea mays Sivaguru Horst 1998 . Root cells division results in root elongation. Aluminum is known to induce a decrease in mitotic activity in many plants and the aluminum-induced reduction in the number of proliferating cells is accompanied by the shortening of the region of cell division in maize Panda 2007 . Blancaflor et al. 1998 have studied Al-induced effects on microtubules and actin microfilaments in elongating cells of maize root apices and related the Al-induced growth inhibition to stabilization of microtubules in the central elongation zone. With respect to growth determinants auxin gibberelic acid and ethylene Al apparently interacts directly and or indirectly with the factors that influence organization of the cytoskeleton such as cytosolic levels of Ca2 Jones et al. 2006 Mg2 and calmodulin Grabski et al. 1998 cellsurface electrical potential Takabatake Shimmen 1997 callose formation Horst et al. 1997 and lipid composition of the plasma membrane. Genetic variability for Al resistance in maize has been reported Jorge Arruda 1997 Pintro et al. 1996 and Al-resistant maize cultivars have been selected for acidic soils Pandey Gardner 1992 . Maize grain-yield .
