Abstract
Effects of temperature upon the germination of the pollen of autumn buckwheat, a common race of it grown in Iwate Prefecture, were investigated. Fresh stigmas were pollinated artificially, and after 5, 10, 30, 60 and 120 minutes, they were fixed and stained in lactic blue. Pollen grains which had germinated and developed long pollen-tubes, the contents, however remaining in the grains were graded as A; pollens, the whole contents of which had passed into the pollen tubes leaving vacant grain bodies, were graded as C; ant those which reached half-way between A and C were graded as B. Germinating pollen grains of A and B grades appeared when the stigmas were kept at 15 to 42°C., but at lower temperatures, C-grade pollens increased in number as time went by, amounting to 65.1 % of the total number. Under the temperatures higher than 42°C, C-grade germination was not observed. In general, at lower tempertures the growth of pollen-tube was slow but continuous, while at higher temperatures it was rapid at the beginning, and stopped soon afterwards leaving germination incomplete. In buckwheat plants, pollen germination was observed to take place at 18 to 30°C., its optimum being about 20°C.
