南方典型红壤丘陵区泡桐幼苗根系的空间分布特征.

: [Objective] The purpose of the study was to analyze the spatial distribution and variation characteristics of Paulownia fortunei ( SeeTTL ) Hems!. roots in the red soil hilly region in southern China, and to provide references for Paulownia cultivation and vegetation restoration in red soil hilly region. [Method] Taking P. fortunei ( Seem. ) Hems!. seedlings with strong enrichment of heavy metal elements and prevention of soil erosion in a typical red soil hilly region as the research object, field investigation was used to investigate the spatial distribution pattern of P. fortunei( Seem. ) Hems!. roots in different diameters( d <0. 5 mm,0. 5 mm,,,;d <2. 0 mm,2. 0 mm,,,;d <3. 0 mm,3. 0 mm,s;d <5. 0 mm and d;;s,5. 0 mm), and to analyze the adaptive ability of Paulownia to the soil. [ Result] In the vertical direction, root length, root surface area and specific root surface area of Paulownia seedlings showed a trend of increasing and then decreasing with the increase of soil depth. Root volume, root dry weight and root tissue density decreased gradually, while specific root length increased gradually with soil depth. Root volume and root surface area for roots of < 3. 0 mm diameter levels and root length for roots of < 5. 0 mm diameter levels showed an increasing and then decreasing trend with soil depth, while root volume, root surface area and root length for other diameter roots decreased gradually. The variability of root surface area and root volume in 0,,,; soil depth ( h) < 10. 0 cm soil layer was significantly stronger than that in other soil layers ( P < 0. 05, the same as below), and the variability of root dry weight was significantly stronger than that in 20. 0 cm.;; h < 50. 0 cm different soil layers. The variability of root length, root volume aud root surface area of roots of 2. 0 mm.;; d < 5. 0 mm diameter levels in 40. 0 cm.;; h < 50. 0 cm soil layer were significantly stronger thau those in other soil layers. In different horizontal positions, root length, root volume aud root surface area for roots of < 2. 0 mm diameter levels were the largest in the profile farthest from the trunk. Root length, root volume aud root surface area for roots of ;;s,2. 0 mm diameter levels were the largest in the profile where the trunk was located. The variability of root length, root volume, root surface area, root dry weight, specific root length, root tissue density and specific root surface area had no significant differences among different profiles ( P > 0. 05). The variability of root length, root volume and root surface area of roots in different diameter levels were the strongest in the profile farthest from the trunk. [ Conclusion] The roots of P. fortunei ( Seem. ) Hems!. seedlings are mainly distributed in the 0 - 20. 0 cm soil layer with obvious surface aggregation. When Paulownia cultivation is carried out, the focus should be on the physicochemical properties of the soil in the 0 - 20. 0 cm soil layer to ensure the efficient absorption and utilization of soil water and fertilizer by the roots of Paulownia. [ABSTRACT FROM AUTHOR]