Abstract
1) Germination was tested, using N (Nasu)-line No. 4 of Italian ryegrass, in glass tray, on filter paper and on soil under almost constant temperature. 2) Germination was good even in low temperature as low as about 5℃ whenever longer gemination period of 30-40 days was allowed and it was as good at 5-30℃. But germination was very bad at 35℃, no germination being observed at 40℃. 3) Water abosorbing speed of the seed was faster at higher temperature and time required to water saturation was the time when figures of treated temperature multiplied by figures of treatment duration reached about 1,500. Further, amount of water absorbed to saturation was almost similar to seed weight. 4) Lower limit of gemination was below 2℃. Germination started on 32nd day at 2℃ and on 29th day at 3℃. But when testing time is limited less than 30 days, lower temperature limit will beat 30℃. 5) By studying effect of high temperature treatment (of 35℃ and 40℃ for 5 and 10 days) to germination, under dry conditions, normal germination like control seed was obtained after exposed to 40℃ for 10 days whenever proper moisture and temperature were given thereafter. But by treatment under humid condition, almost no germination was observed with proper management of moisture and temperature after exposed to moist condition at 40℃ for 10 days. 6) Using filter paper as seed bed, covering seed with stagnated well water niether for short time nor full time gave harmful effect to germination. 7) When soil was used as seed bed, of which moisture at 40%, 60% or 80% of maximum water content of the soil, not withstanding either with soil cover to seed nor without, germination was good. But at 30% soil moisture, germination was extremely bad. At 100% soil moisture, however, germination was good when seed was not covered with soil, but with soil cover the higher the temperature the worse the germination.
