Synthetic auxin’s effect on root hair growth and peroxisomes in Arabidopsis thaliana

(1) Webb School of Knoxville, (2) Biology & Cellular and Molecular Biology, University of Tennessee
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Root hairs are long tubular outgrowths of plant’s root cells that increase water and solute uptake to nurture plants. Root hairs of Arabidopsis thaliana play an important role in studying how auxin affects plants. We investigated the effect of synthetic auxin, naphthalene acetic acid (NAA), on root hair length and peroxisome organelle movement in root hairs. We expected that increasing the concentrations of synthetic auxin in wild-type plants and mutants in class XI myosin, xik and xib would cause an increase in root hair length and linear movement of peroxisomes in the plants. Adding 0.1 µM of NAA to the plant’s growth medium resulted in significantly longer root hairs in wild-type and mutant plants compared to other concentrations tested (0 µM, 0.01 µM, and 1µM). Adding 1 µM of NAA to the plants did not produce significantly longer root hairs compared to 0 µM and 0.1 µM. These data suggest that an increase in auxin can help compensate for the observed impacts caused by the mutants, but that there might be a maximum capacity of auxin intake for a plant to receive optimal growth of root hairs. We found no significant trend for peroxisome movement with an increase of NAA in wild-type and mutant types for linear and wiggling velocity.

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