Initiaton of Roots on Hypocotyl Cuttings of Pinus sylvestris, with Emphasison Direct Rooting, Root Elongation, and Auxin Uptake

1988

6 Abb., 5 Tab., 21 Lit. Ang.

Unselbständiges Werk

9716

200038774

Direct rooting of hypocotyl cuttings of Pinus sylvestris L. is described and compared with rooting via wound tissue. The optimal 3-indolylbutyric acid treatment for direct rooting of Pinus sylvestris hypocotyl cuttings under in vitro conditions was 1.23 mM for 24 h. This treatment resulted in 45% rooting within 3 weeks after cutting. During this period, only direct rooting was observed. Three to 4 weeks after cutting, roots developed either directly on the hypocotyl or via wound tissue. After the first month, rotting took place predominantly via wound tissue. The optimal 3- indolylbutyric acid treatment found for in vitro culture could successfully be used for hydroponic culture (under nonsterile conditions). In vitro culture inhibited root elongation. However, after transfer of rooted cuttings from in vitro to hydroponic culture, root elongation increased markedly. Uptake studies with (Formel) mixed with the nutrient solution showed that auxin uptake by the cutting probably occurred mainly through uptake of the nutrient solution. After 24 h treatment with 1.43 mM 3- indolylacetic acid, the concentration taken up by the cuttings was 0.91 nmol/mg fresh weight. Differences between individual cuttings in auxin uptake could not explain the pood direct rooting of Pinus sylvestris hypocotyl cuttings cultured in vitro.