| Abstract: | During the development of the ovule before pollination, deterioration of successive layers of nucellar tissue, beginning from the nnermost, constantly takes place and consistently forms a zone of disorganization surrounding the periphery of the enlarging embryo sac. Nucellar tissue deteriorates much more profusely near the antipodal end of the sac. "Nuclear extrusion" taken as an indication of intercellular movement of the protoplasm which has undergone partial disassembly, can be seen among the nucellar tissues and between the nucellus and the embryo sac. The intruding nuclear fragments, some of which assume the form of nucleolus, can be found in the antipodal cells. The results interpreted according to our previous hypothesis, are as follows. The nucellar cell by means of intercellular movement of its own protoplasm in the state of partial disassembly, furnishes the embryo sac with composite units of various polymers and organelles. Consequently, the antipodal cells proliferate and flourish The interrelationship between nucellus and embryo sac has been discussed from the viewpoint of supply and utilization of nourishment, which is necessary for the rapid development of the embryo sac. |
