Growth and water relations in mycorrhizal and nonmycorrhizal Pinus halepensis plants in response to drought

Mycorrhizal and nonmycorrhizal Pinus halepensis plants were subjected to wa ter stress by withholding irrigation for four months and then rehydrated fo r 30 d. Water stress affected plants growth and mycorrhizal association was unable to avoid the effects of drought on plant growth. However, when irri gation was re-established the increase in height, number of shoots, total d ry mass, and chlorophyll content in the mycorrhizal plants were greater tha n in non-mycorrhizal plants. The decrease in soil water content decreased t he leaf water potential, leaf pressure potential and stomatal conductance. These decreases were higher for nonmycorrhizal than for mycorrhizal plants, indicating that the mycorrhizal fungi permit a higher water uptake from th e dry soils. The total content of inorganic solutes was not changed by pres ence of mycorrhizae.