North G. B., Nobel P. S., Drought-induced changes in hydraulic conductivity and structure in roots of Ferocactus acanthodes and Opuntia ficus-indica, New Phytologist, 1992, 120(1):9-19, doi: 10.1111/j.1469-8137.1992.tb01053.x
The experiment compares root hydraulic conductivity and anatomy in Ferocactus acanthodes from California and Opuntia ficus-indica before a thirty-day drought and after rewetting. The sections studied differ in age. Flow measurements and microscopic images describe the significance of rhizosheaths, cortical lacunae, periderm and vessel embolism. The rate and extent of functional recovery in surviving roots were also determined.