Induction of hydrotropism in clinorotated seedling roots of Alaska pea, Pisum sativum L.

Roots of the agravitropic pea (Pisum sativum L.) mutant ageotropum show positive hydrotopism, whereas roots of Alaska peas are hydrotropically almost non-responsive. When the gravitropic response was nullified by rotation on clinostats, however, roots of Alaska peas showed unequivocal positive hydrotropism in response to a water potential gradient. These results suggest that roots of Alaska peas possess normal ability to respond hydrotropicallly and their weak hydrotropic response results from a counteracting effect of gravitropism.