Department of Plant Sciences
Long-term and Highly Aluminum-resistant Root Elongation in a Camphor Tree Cinnamomum camphora
- Author(s): Osawa, Hiroki
- et al.
Aluminum ion (Al) is one of the most critical factors that inhibit plant growth in acid soils. Al triggers the rapid inhibition of root elongation at the root apex, although there are great differences in the susceptibility among plant species and cultivars. A number of highly Al-tolerant woody plants can withstand high Al concentrations that exceed the thresholds for most of annual plants. To understand high Al tolerance mechanisms in woody plants, we investigated long-term root elongation and Al accumulation in seedlings of Cinnamomum camphora, a broad-leaved multipurpose tree used in camphor production. Root elongation in C. camphora was only reduced to 70% of the control even at 500 micro M Al for a 60-day pulse exposure period. This Al stress level was tenfold higher when compared with the same Al condition that caused 70% of root elongation inhibition to an Al-resistant wheat cultivar for 48 h. Al accumulation pattern in each organ revealed that the discharge of accumulated Al from the root apex may be partly accounted for the rapid removal of Al in C. camphora. These results suggest that the maintenance of low Al accumulation in the root apex may be an important factor for the long-term Al-resistant root elongation of C. camphora.