We have used a simple and inexpensive, self-built particle acceleration apparatus for direct delivery of DNA to cultured cells of warm-season grasses. High levels of transient expression of the b-glucuronidase gene were obtained following bombardment of embryogenic suspension cells and calli of bahiagrass (Paspalum notatum Flügge) and dallisgrass (Paspalum dilatatum Poir). Furthermore, stable transformed calli of both species have been obtained using this simple particle gun