The effects of Arbuscular mycorrhiza on the growth and physiological characteristics of grafted cucumber under salinity stress

This study aimed to study the mutual effects of grafting and Arbuscular mycorrhiza on cucumber. The experimental design was a factorial experiment based on a randomized block design. Accordingly, treatments were mycorrhiza inoculation including non-inoculation mycorrhiza (AM1) as the control, mycorrhiza with 2400 spores per pot (AM2); and grafting, in which cucumbers (Cucumis sativus var. super daminos) were grafted on Lagenaria siceraria (R2) and non-grafted cucumbers (R1), and the salinity concentration included the control (C), without adding NaCl, medium salinity equal to 30 mM NaCl and high salinity equal to 60 mM NaCl with three replications. The results showed that growth parameters such as the number of male and female flowers, time of appearance of the first male and female flower, the node number of the first female flower, stem length, the number of nodes and leaves, shoot and root fresh weights, were decreased with salinity stress. Grafting also affected the time of appearance of the first male flower and in the node, the number of the first female flower appearance at high and moderate NaCl concentrations. The appearance of the first female flower was postponed under the high concentration of NaCl. Photosynthetic reduction detected in cucumbers subjected to salinity was associated with a decrease in their chlorophyll and mesophyll conductance. In addition to reducing the photosynthesis rate, chlorophyll fluorescence was also affected by moderate and high salinity stress. Generally, grafting and mycorrhiza application decreased the harmful effect of salinity, especially in moderate salinity.