Transient b-glucuronidase reporter gene (GUS) expression was visualised in whole cotyledons of sainfoin (Onobrychis viciifolia Scop.) after microprojectile bombardment with pBI221.23 DNA. Optimum rupture disk pressure and sample plate distance were determined to be 1350 psi and 6 cm, respectively. Mean gold particle diameter of 1.0 µm and 48 h post-bombardment histochemical GUS assay was found to be superior to 1.6 µm gold particles and 120 h post-bombardment GUS assay. Microscopic analysis revealed the localisation of the gold particles predominantly in the epidermal cell layer, whereas less than 1% of the particles were localised in sub-epidermal cells, as deep as three cell layers. Availability of a regeneration protocol from sainfoin cotyledons and the potential of the microprojectile bombardment recommend future applications for obtaining transgenic sainfoin plants.

Transient b-glucuronidase reporter gene (GUS) expression was visualised in whole cotyledons of sainfoin (Onobrychis viciifolia Scop.) after microprojectile bombardment with pBI221.23 DNA. Optimum rupture disk pressure and sample plate distance were determined to be 1350 psi and 6 cm, respectively. Mean gold particle diameter of 1.0 µm and 48 h post-bombardment histochemical GUS assay was found to be superior to 1.6 µm gold particles and 120 h post-bombardment GUS assay. Microscopic analysis revealed the localisation of the gold particles predominantly in the epidermal cell layer, whereas less than 1% of the particles were localised in sub-epidermal cells, as deep as three cell layers. Availability of a regeneration protocol from sainfoin cotyledons and the potential of the microprojectile bombardment recommend future applications for obtaining transgenic sainfoin plants.