Efficient plant regeneration of Larix kaempferi

Abstract

ABSTRACT Embryogenic tissues of Japanese larch (Larix kaempferi Lamb. = L. leptolepis Gord.) which were induced and maintained on the modified Campbell and Durzan (mCD) medium with 7 μM of 2,4-dichlorophenoxyacetic acid (2,4-D), 3 μM of N 6 -benzyladenine (BA), consisted of distinctive aggregates composed of small cytoplasm-rich cells and elongated suspensor- like cells. The small aggregates showed competence for both proliferation and differentiation with dynamic morphogenic changes. We selected two embryogenic cell lines with different morphologies and studied the effects of abscisic acid (ABA) on maturation and germination of somatic embryos from these lines. Our studies indicated that the ABA requirement for maturation varied in relation to cell line morphology. Based on these results, an efficient embryogenic suspension cell line was developed with reproducible morphological and developmental characteristics. We found that in high cell density cultures, although embryogenic cells continued to proliferate, no further development occurred. In low cell density cultures, development of distinctive cell aggregates into somatic embryos was promoted. Thus, by manipulating the culture cell density, an efficient production of uniform somatic embryos of Japanese larch is possible.