Transformation of Maize Immature Embryos with Trehalose Synthase Gene THE COMPARISON OF THE DYNAMIC CHANGES OF ENDOGENOUS HORMONES IN CALLUS BETWEEN MATURE AND IMMATURE EMBRYOS OF MAIZE Plantlets Regeneration from Immature Embryos and Cotyledons of Peach EFFECTS OF DIFFERENT AUXINS AND COMBINING APPLICATION WITH ABA ON REGENERATION OF IMMATURE EMBRYOS OF WHEAT Regeneration culture from bombarded immature embryos of wheats and transgenic plant STUDY ON IN VITRO CULTURE OF IMMATURE EMBRYO OF FRAXINUS MANDSHURICA