FACTORS INFLUENCING GERMINATION AND GROWTH OF ISOLATED EMBRYOS OF PINUS HELDREICHII

Abstract — The effects of nutritional, hormonal, and physical factors on the germination and growth of isolated mature zygotic embryos of Pinus heldreichii were studied under in vitro conditions. The optimum medium for embryo germination and adequate conversion into seedlings was basal Gresshoff and Doy (1GD) medium. All tested carbohydrates at the applied concentrations stimulated embryo growth, but only 3 % sucrose increased embryo germination compared to the control, while maltose had an inhibitory effect. Among the applied plant growth regulators, only gibberelic acid (GA3) had a few benefits on the development of isolated embryos into plantlets, while the others had a negative effect. Embryos cultured on an agar-solidified medium grew better and the germination percentage was higher than in a liquid medium. Light treatment did not affect embryo germination, but generally stimulated seedling growth