In Vitro Propagation of Hosta decorata ‘Thomas Hogg’ Using Cultured Shoot Tips

Abstract

Abstract Shoot tips proliferated in vitro were used as explants to determine the effects of various nutrient medium components and environmental conditions on shoot multiplication of Hosta decorata L. H. Bailey ‘Thomas Hogg’. The rate of axillary shoot multiplication was stimulated by the addition of either 0.01 or 0.10 mg×liter α-naphthaleneacetic acid (NAA) to medium containing 5 mg×liter 6-benzylamino purine (BA). Indoleacetic acid (IAA) and indolebutyric acid (IBA) did not promote axillary shoot formation. All 3 auxins were effective in promoting adventitious shoot initiation. In medium with 0.1 mg/liter NAA, BA at 5 mg/liter stimulated a higher number of shoots of axillary origin than did N6-isopentenylaminopurine (2iP) or N6-furfurylaminopurine (kinetin). However, equivalent or greater proliferation of adventitious shoots was achieved with 2iP or kinetin. Sucrose was essential for shoot multiplication and 30 g×liter was optimum. Inorganic phosphate (NaH2PO4 · H2O) and adenine sulfate stimulated growth and shoot multiplication while i-inositol, although not essential, enhanced shoot formation at 30 mg×liter. Axillary and adventitious shoot multiplication was optimum under photosynthetkally active radiation (PAR) of 70 or 130µE m-2s-1 at 21°C and under PAR of 70 µE m-2s-1 at 26°C. Rooting of shoots in vitro was obtained on basal medium without growth regulators or on medium containing 0.01 mg/liter NAA, and the plants were successfully established in soil. Plants obtained from culture which had lost leaf margin variegation regained it after receiving a cold room treatment of 3-6°C for 20 weeks.