Investigators of pollen germination and pollen tube growth in vitro have employed various methods of culturing, usually involving a thin liquid pollen suspension in petri dishes or drops on glass slides (Linskens 1964, 1967a, b). Effects of different substances on germination percentage and pollen tube length are tested under these conditions. For investigation of chemotropical activity, the pollen is often germinated on solid substrates such as gelatin and agar (Rosen 1964; Mascarenhas & Machlis 1962). In all of these techniques, the experimental measurements are made microscopically, so that only a small amount of pollen, less than 1 mg in each experiment, can be used. However, for biochemical analyses of pollen and pollen tubes, larger amounts of germinating pollen grains are necessary (Mascarenhas 1966; Linskens 1967 a). At the same time, it is desirable that the medium remains homogeneous during the experiment, that optimal supplies of nutrients are available and that the germination process starts synchronously.