Germinating Time of Pinus tabulaeformis and Platycladus orientalis

On the light of the theory of cumulative temperature,seeds of Pinus tabulaeformis and Platyladus orientalis were germinated under 15℃,20℃,25℃ temperature respectively .Statistical analysis on testing of the germination rate and time of seeds, the result showed that biological starting temperature of both P. tabulaeformisand P. orientalis were 10℃,the valid cumulative temperature of seeds germinating of P. tabulaeformis was 90℃ and that of P. orientalis 100℃. The method of forecasting germination time is given.