bor1-1, an Arabidopsis thaliana Mutant That Requires a High Level of Boron

Abstract

Bor1–1 (high boron requiring), an Arabidopsis thaliana mutant that requires a high level of B, was isolated. When the B concentration in the medium was reduced to 3 [mu]M, the expansion of rosette leaves was severely affected in bor1–1 but not in wild-type plants. In a medium containing 30 [mu]M B the mutant grew normally but showed female sterility, whereas the wild type was able to set seeds. These defects of the bor1–1 mutant were not detected with supplementation of 100 [mu]M B. In vivo concentrations of B in bor1–1 mutants were lower than those of the wild type, especially in the inflorescence stems. Tracer experiments using 10B suggested that the mutant has defects in uptake and/or translocation of B. The mutation was mapped on the lower arm of chromosome 2.