Studies on the Respiration of Pollen of Corn Plant (Preliminary report)

Abstract

In contrast with many detailed studies having hitherto been made on various aspects of the pollen germination, rather very few reports (OKUNUKI (1932, 33) in lily (Lilinm auratum, LINDL) and tea (Thea sinensis, L.)) are found on problems of respiration of pollen. The author has made experiments on pollen respiration of corn plants. Pollens were collected from plants of a newly bred variety Choko-202. In collecting pollens, the method of' YAMASAKI (1943) was used, and the respiration rate of pollens were measured by WARBURG respirometer. The main results were as follows: (1) Relation of sucrose concentration in medium to the respiration of pollen grains. -The respiration rate was small under low concentration (0, 10 %) of sucrose, and it rose as the concentration increased up to 30%, decreasing again at 40%. (2) Effects of humidity during storage on the viability of pollen grains. -When stored for 24 hours, pollens which were stored under high humidity (50, 80 %) held higher respiration rate than those under low humidity (0, 30%) and the maximum rate was observed at a relative humidity of 80%. In addition, when stored for 48 hours, the respiration rate became very low under all humidity conditions. (3) Effects of temperature on the respiration of pollen grains. -The respiration rate increased gradually as the temperature rose from 25° to 45°C, and it reached maximum at 40° to 45°C. Then, the rate fell rapidly at 50°C, and became zero at 70°C.