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The Development of Embryo and Endosperm in Eleutherococcus senticosus (Araliaceae)


The embryo development of Eleutherococcus senticosus (Rupr. et Maxim. )Max-
im. was of the Solanad type. The fertilized egg usually underwent a rest period of 15 days
before embarking on its first division. And the first division of the zygote took place after the
cellularization of endosperm free nuclei. After the club- shaped and the globular embryo period,  the heart-shaped embryo developed when the fruit became ripe. From the late clubshaped to early heart-shaped embryo stage, the suspensor grew to its maximum length. The endosperm development of Eleutherococcus senticosus was of the Nuclear type. The rest period of primary endosperm nucleus was about 1 day long. When the number of endosperm free nuclei reached 200~300, the endosperm cellularized through free-growing-wall formation. The endosperm cells divided by typical mitosis and got filled with reserve food. But in a small number of seeds, there were some huge endosperm cells with a huge nucleus. The endothelium differentiated from the inner epidermis of integument when the number of endosperm free
nuclei had increased to 32~64, and disintegrated when the embryo developed into the globu-
lar stage. After the disintegration of endothelium, the epidermal cells of endosperm differen-
tiated into a secretory layer. From the globular embryo to heart-shaped embryo stage, disin-
tegration of embryo and endosperm occurred in about 5 % seeds. In the mature fruits, there
were a large amount of shrivelled and insect-bitten seeds, and the pulmp seeds made up about
40% of the total. The pulmp seeds were mainly occupied by the endosperm, with a very
small embryo. The nutrients of the embryo and endosperm at different stages of development
are also discussed.


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