Vegetative propagation of oak (Quercus robur and Q petraea) by cutting and tissue culture

Abstract

The potential of cuttings of Quercus robur and Q petraea to form adventitious roots decreased rapidly with increasing plant age. The rooting ability of older plants was increased by hedging. Hedging of stock plants offers an effective technique for the production of cuttings with high rooting potential. Stock plant environment markedly affected rooting of leafy cuttings. A high percentage of cuttings collected from plants grown under continuous light rooted. Vigorous plants were produced from cuttings which rooted quickly and were capable of rapid shoot growth immediately after rooting. Shoot growth of rooted cuttings was stimulated in suitable environmental conditions by sufficient mineral nutrition. Rooted cuttings which formed new long shoots and wintered in rooting medium in the same place in an unheated greenhouse exhibited high survival rates. For tissue culture propagation, 2 methods were used: micropropagation by axillary shoot multiplication and by somatic embryogenesis. Axillary shoot multiplication was stimulated on low salt media (BTM, or woody plant medium WPM) supplemented with a low concentration of benzylaminopurine (BAP) or N-benzyl -9-(2-tetrahydropyranyl) adenine (BPA) (0.2-0.6 mg·l-1). Rooting of microshoots was achieved in vitro and was also successful under non-sterile conditions in a rooting mixture of peat and perlite. The field growth of micropropagated trees was comparable to that of control seedlings. Embryogenic cultures were initiated from immature zygotic embryos of Q petraea cultured on modified Schenk and Hildebrandt (SH) medium supplemented with BAP (1mg·l-1). The majority of embryogenic cultures produced somatic embryos. The conversion of somatic embryos into plantlets was achieved after cold and desiccation treatment. Plantlets regenerated from somatic embryos were transplanted into potting mixture, where growth continued.