effect of arbuscular mycorrhizae and drought stress on growth indexes, water relations and proline as well as soluble carbohydrate content in pistachio (pistacia vera l.) rootstock seedlings

in order to investigate the effect of two mycorrhizal species (glomus mosseae and g. intraradices) on different growth aspects of two pistachio cultivars (p. vera cv. badami-riz zarand, and p. vera cv. qazvini), a greenhouse experiment was conducted taking into account three factors of: mycorrhizae inoculation at three levels (no mycorrhizae application as control, g. mosseae , g. intraradices), drought stress at four levels (100% fc as control, 75% fc, 50% fc, and 25% fc) as well as two pistachio cultivars (p. vera cv. badami- riz zarand and p. vera cv. qazvini) in a completely randomized design of three replicates. the results indicated that three months past the commencement of the drought, such vegetative traits as stem height and diameter, leaf area, as well as dry weights of leaf, stem and root decreased with increase in drought intensity. plant-water relation parameters including relative water content, and water use efficiency were severely lowered as a result of the drought inflicted. in response to drought stress, osmo-regulation reactions were activated in pistachio plants, leading to an increase in proline and soluble carbohydrate content in plant leaves. application of mycorrhizae considerably improved the vegetative growth in pistachio plants where g. mosseae and g. intraradices applications promoted stem height by 100%, and 75% respectively, and in comparison with control. plant-water relations in mycorrhizal treated plants were superior over non-mycorrhizal applied plants. furthermore, the results indicated that proline and soluble carbohydrate accumulations were higher in leaf while lower in roots of mycorrhizal inoculated plants as compared with control.