Characterization of hydrotropism: the timing of perception and signal movement from the root cap in the agravitropic pea mutant ageotropum.

In recent years, experiments have demonstrated that the gravity response of roots can be separated from the hydrotropic response by using the agravitropic pea mutant ageotropum. Though this mutant has been a useful tool for demonstrating the existence of the hydrotropic response of roots, little is known about how perception, transduction, transmission, and the growth response is accomplished. In this study, we have used the ageotropum mutant to investigate both the threshold time for perception of an osmotic stimulation and the minimum time required for signal transduction and transmission in roots following an osmotic stimulation at the root cap. In addition, we have compared the threshold times and signal transmission times of hydrotropism in the ageotropum roots to the gravity response of Alaska pea roots.