EMBRYOGENESIS FROM MICROSPORES OF GINKGO-BILOBA L, A MEDICINAL WOODY SPECIES

The present work establishes that isolated microspores of Ginkgo bilob a L. cultured at densities of 1.5 to 5.10(4) per milliliter in Bourgin and Nitsch (1967) liquid medium are able to divide, both in the prese nce and in the absence of exogenous growth regulators, and to germinat e by growing a pollen tube. In all experiments the microspores exhibit ed various modes of division leading to embryo formation in the liquid medium. Four weeks later, the microspores which had been previously s ubmitted to various electrical stresses showed pro-embryo development earlier than those which had not. After ten weeks the number of embryo s was found to be 300 to 5300 ml-1 following the experiments. When the embryos exhibited a slower growth in liquid medium, they were transfe rred onto various solid media for maturation. Two months later, embryo s had proliferated visibly.