Effects of arbuscular mycorrhizal fungi on the growth and drought resistance of Amorpha fruticosa under water stress.

A pot experiment was conducted to study the effects of arbuscular mycorrhizal fungi (AMF) on the growth and drought tolerance of Amorpha fruticosa under water stress. The results showed that, with different water treatments, the height, root activity, dry weight of shoots and roots of inoculated plants were higher than those of non-inoculated plants. Mycorrhizal colonization rates under water stress were significantly higher than those under well-watered conditions. At different water-stress periods, the contents of proline, soluble sugar and soluble protein were significantly increased by inoculating AMF, especially at the later period when the content of proline in AMF plants increased dramatically under severe stress and moderate stress. Additionally, inoculation of AMF could promote the activities of antioxidative enzymes in A. fruticosa and maintain them at a high level. Fv / Fm decreased with the reduction of soil relative water content and AMF plants always had a higher Fv / Fm value than non-AMF plants over the whole period. ETR and qL decreased at the middle period while the period of water stress was extended, and the values of two parameters could return to almost the original levels in the AMF plants at the later period; however they could not in the non-AMF plants. AMF plants had a lower NPQ than non-AMF plants at all water conditions. The results show that in the drought condition, inoculating AMF could increase the growth and drought resistance of A. fruticosa by keeping the chlorophyll fluorescence parameters stable, promoting the activities of roots, accumulation of osmolytes and activities of antioxidative enzymes.