There is no ~3H-tymidine incorporation into vegetative nucleus (Vn),generative nucleus (Gn) or nu- cleus of sperm in 96 hours before dehiscence of anthers (BDA).

• 散粉前96小时至精细胞形成,营养核、生殖核和精于核中均未见~3H-胸苷掺入。