XVI International Botanical Congess

A mutant altered in root gravity response and the production of rootwaves has been identified from a dSpm mutagenized seed collection. Root waves, or induced undulations in root tip orientation that produce a wave like pattern along the length of a root, are thought to be a combined response to gravity and touch. Mutant seedlings do not form the usual root wave pattern on a tilted hard agar surface, but grow in loose coils, as do many gravitropism mutants. Gravity response studies show that mutant roots are less closely aligned to a single gravity vector than those of wild type seedlings. This mutant shows no alterations in starch content or in exogenous auxin induced growth inhibition, two common factors that affect gravitropism. Genetic analysis shows that this trait segregates as a single nuclear recessive locus, and preliminary evidence suggests that a dSpm element may be linked to the mutation. Work is in progress to identify the sequence flanking this element and to further characterize the mutant.