N. Brassard et al., ELONGATION, ROOTING AND ACCLIMATIZATION OF MICROPROPAGATED SHOOTS FROM MATURE MATERIAL OF HYBRID LARCH, Plant cell, tissue and organ culture, 44(1), 1996, pp. 37-44
Factors were defined for elongation, rooting and acclimatization of mi
cropropagated shoots of Larix x eurolepis Henry initiated from short s
hoot buds of plagiotropic stecklings serially propagated for 9 years f
rom an 8-year-old tree. Initiation and multiplication were on Schenk a
nd Hildebrandt (SH) medium supplemented with 5 mu M 6- benzyladenine (
BA) and 1 mu M indole-butyric acid (IBA). Stem elongation was obtained
in 36% of the shoots on SH medium containing 0.5 mu M BA and 63% of t
he remaining non-elongated shoots initiated stem elongation after tran
sfer on SH medium devoid of growth regulators. Rooting involved 2 step
s: root induction on Campbell and Durzan mineral salts and Murashige a
nd Skoog organic elements, both half-strength (CD-MS/2), supplemented
with 1 mu M of both naphthaleneacetic acid (NAA) and IBA, and root elo
ngation following transfer to CD-MS/2 medium devoid of growth regulato
rs. Repeating this 2-step sequence yielded up to 67% rooted shoots. Ac
climatization of plantlets ranged from 83% to 100%. Over 300 plants we
re transferred to the greenhouse; some showed plagiotropic growth.