The Effect of the Female Gametophyte on the Growth of Cultured Douglas-fir Embryos

Several clones of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, embryos grown in aseptic culture in the presence or absence of the female gametophyte or a crushed aqueous extract of it, have shown striking differences in overall length, size and substance(s) responsible for this colour of the cotyledons and in root length. The growth-promoting effect is diffusible in agar, heat-stable and has detectable activity at a concentration of about 0·1 to 1·0 per cent (v/v) in a basal nutrient medium. Evidence is provided that extracts of gametophyte may have synergistic effects with coconut water in promoting morphogenesis of Douglas-fir cells in suspension culture.