In vitro regeneration of plantlets from mature embryos of Pinus ayacahuite.
A plantlet regeneration protocol was developed for Pinus ayacahuite var. ayacahuite (Ehrenb.). Embryos from mature seeds from ten provenances were cultured in a 16-h photoperiod for 3 days on a medium containing 30 mM sucrose and 0.7% agar. Cotyledons from these embryos were subcultured onto MCM medium (Bornman 1983) supplemented with 50 micro M N(6)-benzyladenine and 90 mM sucrose for 2 weeks. Bud development and shoot elongation were maximized by subculturing the explants on half strength AE medium (von Arnold and Ericksson 1981), supplemented with 60 mM sucrose and 0.05% activated charcoal every 30 days. Seed source had a significant effect on the responses of the embryos to the bud induction protocol. For the provenance with the best response to bud induction, about 79% of the cultured cotyledons formed buds, and each cotyledon formed a mean of 9.1 buds, so that about 70 shoots could be induced from each seed. The best rooting response (40% rooting) was obtained by treating the shoots for 8 h with 100 micro M naphthalene acetic acid.
Saborio
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Plant Physiology Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada.
Dvorak
W S
WS
Donahue
J K
JK
Thorpe
T A
TA