Study On Ultrastructure Of Embryo And Endosperm Development In Soybean

Soybean is the genus butterfly flower subfamily for leguminous plants, and it’s very widely planted all over the world. Soybean is a kind of main grains and oil crops in China, and also has many different kinds of functions and uses. Therefore, it occupies the main position in the agricultural production in our country, and it’s also an important part in the composition of world’s food and oil crops world.In this paper, we chose Soybean Dongnong 46 as the text materials. We want to study the ultrastructure of the process of soybean growth and development of embryo and endosperm furtherly by means of TEM and optical microscope combined with the technology of semi thin section and ultrathin section. To understand the mechanism in the process of its development and fully understand the characteristics of ultrastructural of soybean,we must be based on the micro structure and studied deeply in the research that many scholars got in the past. The purpose of this study is to provide theoretical support for the improvement of value-added soybean yield and the research of soybean embryo.The experimental results are as follows:1. The first division of the endosperm of soybean was horizontal split for a basal cell and an apical cell from the period of two-celled embryo to the period of heart-shaped embryo. The volume of the basal cell was significantly bigger than that the apical cell, and there was significant internal conflict in micropylar end walls. When it was in a eight-celled stage of embryo, the cystic substances went into the micropylar end cell. When it had developed the globular embryo in the soybean, the suspensor was made up with 4 cells in the single row.The suspensor was made up with 3-4 row cells,and there were a large vacuolization in the part of the cells in the period of heart-shaped embryo of soybean.2. A plenty of plasma membranes had happened to invaginate, and there were many mitochondrias, golgi apparatus and small bubble materials to be distributed surround the plasma membrane when the embryo were developing. There were also the structure of small vesicles between plasma membranes and the cell walls of embryo in soybean.3. Osmiophilic particles were not found in them during the two-celled embryo stage and rod-shaped embryo stage. When it developed to the globular and heart-shaped embryo in this process of embryo development of soybean, there were osmiophilic particles on the place which between endosperm and embryo cell, and they also appeared in suspensor cells and inner integument cells which they were on the end of micropyl.4. The coated vesicles were existed in the endosperm when the endosperm of soybean were developing. And it was the most in the content of organelles when was in the period of free nuclear endosperm. When it was in the early period that endosperm had started to form cells, a large number of coated vesicles distributed in the position which near the free growth walls and there were a lot of coated vesicles on the growth of the cell wall extending direction when endosperm free wall formed. So the coated vesicles participated to form the cell walls of endosperm.The cells were formed earliest on the end of micropyl, then it began to formed cells from sac wall to the center in the period of cellularization. We think they can provide nutritions for embryo development.5. There were a lot of phagmoplasts in the endosperm when it became cells in a wheat, but they didn’t appear in the cytoplasm of soybean.Cell wall was formed by free growth wall.6. Soybeans were nuclear endosperm development. It had a haustorium on the end of chalazal in a embryo sac. A number of free nuclears gathered on the end of chalazal when the other endosperm had became cells. They kept nuclear cell body and inserted organization. There were a lot of wall ingrowths in the part of touching on the surrounding tissues and there were a lot of fat bodies in the clearance.7. Inner integuments were two layers of cells which outside of integument tapetum. They contained abundant starch grains and other organelles in the inner integument cells. In this process of embryo development, they appeared decline phenomenon that they were foud to shrink, deformate and disintegrate. Finally the inner integument cells occurrenced programmed cell death. They provided nutritions and spaces for development.8. Endosperm was free nuclear in the early period. The endosperm cells which surrouding the embryo gradually began to disintegrate around the embryo after free nuclear had became endosperm cells in the period of globular embryo. There are some osmiophilic substances surrounding the embryo afer the hydrolyzate disappeared. In the end, endosperm cells occurrenced PCD. They provided nutritions and spaces for embryo development.