Assessment of Paulownia tomentosa Steud. Regeneration Capacity Through Root Cutting Diameters, Growth Hormone doses and Soil Types

This investigation proposes an effective protocol (cutting) for Paulownia tomentosa production in Tunisia during the 2022–2024 period. The effects of the three interactive parameters: root cutting diameter (L1, 0.5; L2, 0.8; L3, 1.25; and L4, 2 cm), indole-3-butyric acid (IBA) hormone concentrations (C, 0; T1, 0.1%; and T2, 0.3%), and soil type (S1: 50% silt + 50% potting soil, and S2: 43% potting soil + 43% silt + 14% sand), were investigated. The data showed that cutting roots with 0.5 cm dimensions, a cutting treatment with hormone (0.3%), and the S2 soil type corresponded to a growth enhancement in height. These results revealed the broad changes in flowering of P. tomentosa. Also, data revealed that the root cutting diameter had the greatest influence on the biochemical contents of 4-month-old P. tomentosa sprouts. The studied pathway revealed that the auxin precursor IBA contributes toward active auxin [indole-3-acetic acid (IAA)] biosynthesis. Overall, this study found substantial changes in the morphological, biochemical, and floral features of new P. tomentosa sprouts under the interactive factors. To summarize, vegetative propagation of Paulownia, particularly through root cutting, allows for proliferation and plantation development. These findings can be applied to future breeding efforts with Paulownia to improve and protect it as a woody species, forage, and medicinal plant.