R. Hillelucidated quantitative evolution ofoxygen by isolated chloroplasts in 1937. His discovery made a substantial contribution to the advancement of the study of photosynthesis. Hill’s experiments comprised the three interesting methods ; the use of (1) ferricion as the electron acceptor, (2) hemoglobin as the measuring system ofoxygen evolution, and (3) isolated chloroplasts as the light reaction system.

Since high school students today only memorize the light reaction as the process to produce ATP and oxygen, and to genarate reducing power (XH₂), the light reaction itselfremain in a black box for them. They would hardly realize the light reaction without recognition of the existence of electron flow in chloroplasts. By studying Hill’s experiments ata high school, the students notonly understand exactly the light reaction, but also they have a chance to approach Hill’s originality. It seems to be very valuable for them to trace his experiments.

The purpose ofthis paper is to discuss the background ofthe use offerric ion, the quantitative analysis of evolved oxygen, and the method of chloroplastisolation following his original papers. Finally, I state how to treat the Hillreaction in bilolgical education ofthe high school.

In ciliate Euplotes, the special structure called replication band (RB) appears on the S-phase nucleus. The RB can be easily observed in the nucleistained with aceticcarmine. By using the ciliate with this unique phenomenon, the cell cycle was especially examined on the relationships between the cell growth and the cell cycle, and also between the conjugation and the cell cycle. The ciliate is discussed as teaching materials for cell cycle.

A simple method for photoreversibility ofgerminationin Grand Rapids lettuce (Lactuca sativa L.) seed was demonstrated using colour cellophane and overhead projector.Red and far-red light were provided by a halogen lamp (100V, 500W) ofoverhead projector with filters ofcolour cellophane. Lettuce seed showed completely reversible photoreaction at 28-30°C. In order to observe photoreversibility of germination in lettuce seed, itis the bestway to givelightirradiation, 0-6h after sawing at 28°C and 2-6h after thatat 30°C.