Abstract
Pollen tube m itoses and male gamete formation in many, though not all, angio-sperm species with binucleate pollen can be examined after germinating the pollen in a medium containing H3BO3, 0.01 gm; Ca(NO3)2.4H2O, 03 gm; MgSO4. 7H2O, 0.02 gm; KNO3, 0.01 gm; sucrose, 10 gm; and water, 100 ml. Dry pollen is scattered on a drop of medium placed on a clean slide resting on moist filter paper in a closed Petri dish. After about 24 hr, the medium is drawn off and the pollen tubes are stained and squashed in propionic-orcein. The vapor given off by crystals of acenaphthene, placed on the filter paper when the cultures are set up, inhibit the mltotic spindle. Metaphase stages accumulate in which the chromosome complement can be studied.