• 生长速度常数（R） n ㏒ x2 - ㏒ x1 R = = t2 – t1 t2 – t1 • 代时(G) 1 t2 – t1 G = = R 3.322(㏒ x2 - ㏒ x1 )• 生长速度常数（R） n ㏒ x2 - ㏒ x1 R = = t2 – t1 t2 – t1 • 代时(G) 1 t2 – t1 G = = R 3.322(㏒ x2 - ㏒ x1 )