Abstract: [Objective] The objectives of this study were to deepen the understanding of air-cutting mechanism and to provide theoretical basis for popularizing the air-cutting technique. [Method] One-year-old Manchurian ash Fraxinus mandshurica seedlings grown in two types of containers (non-waven bags and plastic containers) were used to investigate the effects of air cutting on growth (height, stem collar diameter), morphology (e.g. total leaf area, root diameter) and biomass of different organs above- and under-ground, as well as on root development. [Results] The height, the ratio of height to diameter, the total leaf area and the quality index of seedlings in non-woven bags were all significantly (P<0.05) larger than those in plastic containers. The individual plant biomass, the total nitrogen and total phosphorus contents of seedlings in non-woven container were 6.98%, 12.09%, and 10.3% higher than those in plastic container, respectively, the root length, the root superficial area, and the root apical number were 14.56%, 32.91%,and 11.18% greater (P<0.05) respectively than those in plastic containers. Air cutting significantly increased the number of lateral roots more than 0.5 mm at diameter (P<0.05). More dead cells of root apical meristem were found in seedlings under air-cutting treatment, however, the number of sprouted lateral roots in mature zone of these seedlings was 35.34% higher than those in control (P<0.05).[Conclusion] Our findings indicated that air-cutting inhibited root apical growth and increased the number of lateral roots and root biomass, which may greatly promote the growth in height and leaf area, and result in improved quality of Manchurian ash seedlings.

Key words: Fraxinus mandshurica, non-woven bags, plastic container, air-cutting, root anatomy, maturation zone, anlage of lateral root