The Embryological Studies of Interspecific Hybrids between Liriodendron tulipifera L, and L. chinense(Hesml.)Sarg.

The embryogenesis of interspecific hybrids between Liriodendron tulipifera and L. chinense was studied by means of artificial pollination and routine paraffin-embedded sectioning technique. The results were:(1)The pollen of L. tulipifera germinated normally after artificial pollination,and more pollen tubes could grow into stigma but a lot of pollen tubes grew slowly and even broke up in the style canal;(2)When the pollen has germinated for six days,the pollen tube reached the embryo sac finally through the style canal,obturator and nucellar cap,then,the porogamy was conducted.After 20 days, the cellular endosperm was formed first as a narrow tissue of 2 to 4 eclls in thickness. The spherical embryo could be observed after 35 days;(3)The seed coat was formed by integment following the development of embryo and endosperm. The antropous has two layers integments. Both of them were formed exopleura, middle layer and endopleura. Each layer of integment experienced a series of changs when the embryo and endosperm developed. At last,the seed Coat was consisted of the membrane layer formed by exopleura of exointegment, air chamer formed by middle layer and hardening layers formed by the endopleura cell of inter integument and outer integument;(4)The number of mature embryo sacs and pollen tubes reaching micropyle was too less to fertilize;(5)The course of fertilization was normal on the whole,but the development of embryo and endosperm was not in harmony, which resulted in the early abortion of embryo,so it was difficult to observe the later development of embryo.