Chemotaxis of Bracken Spermatozoids

In the original experiments on the chemotaxis of fern spermatozoids, Pfeffer (1884) inserted small glass capillaries filled with a sodium malate solution into suspensions of spermatozoids, and observed that chemotactic aggregation resulted from precise orientation of the spermatozoids to the gradients produced by diffusion of malate from the open tip of the capillary. More recently, Rothschild (1952) provided definite confirmation of the precision of orientation in a chemical gradient by cinemicrographic records of chemotaxis, using bracken spermatozoids.