Micro- and Cutting Propagation of Silver Maple. I. Results with Adult and Juvenile Propagules

Abstract

Clonal micropropagation studies with silver maple (Acer saccharinum L.) included experiments with various shoot. explant types, cytokinins, and stock plant maturation levels. These trials led to successful explant establishment, axillary shoot proliferation, rooting of microshoots, and establishment of plantlets in the greenhouse. Overall, the best cytokinin tested was the phenylurea derivative TDZ. Shoot proliferation on juvenile explants was poor with kinetin, 2iP, and BA. Only zeatin at 10 μ m was comparable to TDZ. TDZ at 10 n m was optimal for both juvenile and adult nodal explants. Juvenile explants that were held in vitro for 4 months commonly had at least 60 axillary shoots that could be subculture or excised for rooting. Microshoots rooted within 2 weeks. Following rooting, silver maple plantlets could be transplanted into a growing medium and placed directly onto a greenhouse bench. Studies were also conducted on rooting stem cuttings (macropropagation). Single nodes from juvenile plants rooted under intermittent mist, regardless of auxin application; however, shoot-tip cuttings from adult trees rooted best when auxin in ethanol solution was applied. Chemical names used: N- phenyl- N' -1,2,3 -thiadiazol-5-ylurea (thidiazuron, TDZ), N- (2-furanylmethyl)-1H-purin-6-amine (kinetin), isopentenyladenine (2iP), benzyladenine (BA), (E)-2-methyl-4-(1H-purin-6-ylamino)-2-buten-1-ol (zeatin).