Photomixotrophism on in vitro elongation of Corymbia hybrid clones

Abstract

The importance of Corymbia species and their interspecific hybrids has been evidenced in forestry programs, due to their wood quality and adaptation to various environmental conditions. To solve the in vitro culture limiting factors of a hybrid Corymbia citriodora × C. torelliana and three C. torelliana × C. citriodora hybrid clones, the present work aimed to evaluate the influence of photomixotrophism on the in vitro elongation phase. The tissues used to obtain the explants were nodal segments from ministumps of the four hybrid clones. The effect of photomixotrophism was assessed by three light sources (fluorescent lamp, white LEDs and red/blue LEDs); three sucrose concentrations (0, 15 and 30 g L-1) and two sealing forms (rigid membrane less polypropylene caps and two membranes). Data on shoot length and number per explant, vigor, shoot oxidation and photosynthetic pigment content were collected at 35 days of in vitro culture. Based on the results obtained, it can be inferred that red/blue LEDs, 15 g L-1 sucrose and membrane less vials are more suitable for in vitro elongation of hybrid clones C. citriodora × C. torelliana and C. torelliana × C. citriodora, without prejudice to the development of shoots intended for the production of micropropagated clonal plants.