In 1970s, Murahig, a Japanese-American scholar, summed up the whole process of plant reproduction in a factory through his own research. He believes that different measures should be taken in three different stages of plant reproduction industrialization. The first stage is to establish explants (explants are plants or plant parts used for artificial culture); The second stage is the proliferation and rooting of buds; The third stage is the exercise before transplanting the test-tube seedlings. Different culture media and culture conditions must be adopted in each stage. Since then, shoot tip culture and factory propagation of plants have been widely used in practice as important contents of cell engineering. The plant breeding factory that agricultural workers dreamed of has come true.