Effects of vesicular-arbuscular mycorrhiza on the protective system in strawberry leaves under drought stress

Vesicular-arbuscular mycorrhiza (VAM) plays a very important role in improving plant drought resistance abilities. A pot experiment was conducted during the 2008–2009 strawberry growing season in the greenhouse at Baoding, Hebei Province, China, aiming at exploring the influence of VAM on the drought tolerance of strawberry and elucidating the interaction mechanism. Three treatments were designed in our study, including routine water supply treatment (CK-WW), drought stress treatment with VAM fungi (GM-DS), and drought stress treatment without VAM fungi (CK-DS). Four indicators of each treatment were measured, respectively, including protective enzyme activity, pigment content, plasma membrane, and osmoregulation. The results showed that the treatment inoculated VAM fungi can increase the protective enzyme activity, osmoregulation, and antioxidant capacity membranaceous, especially the activity of catalase (CAT) and ascorbate peroxidase (APX). Inoculating strawberry plants with VAM fungi under drought stress could also lead to increasing the content of leaf pigment, accelerating the accumulation of free praline and soluble protein, improving the transport speed of soluble sugar, restraining the decomposition of chlorophyll, decreasing the malondialdehyde content and plasma membrane conductivity, and improving the H⁺-ATPase activity.