The Pattern of Water Absorption in Rice Seed during the Germination. : I. The relationship between the pattern and the germination velocity.

Abstract

1) The pattern of water absorption in rice seed. is divided into three phases i. e. the imbibition stage (phase A), the germination stage (phase B) and the growth stage (phase C). From the view point of water absorption in seed, the velocity of germination is regulated by two factors, phase A and phase B. 2) Phase A shows the process of the initial excessive water absorption which continues for 18-24 hr. when imbibition for whole seed is finished. Phase B shows the stage of organization for germination. At this phase the increase of water absorption is not remarkable : if it happens, the rising is dull. The last period of phase B means the germination, that is, the appearance of tissue of embryo through its surrounding coats. Phase C is the secondary visible water absorption and it is concerned with the growth after germination. 3) The seed coat is the main factor regulating the phase A. Phase B may be mainly governed by the activation of aleurone layer and the translocation of some substance for activation in embryo through the vascular bundle in the seed coat and hydrolysis in endosperm. 4) Phase B is apt to be more affected than phase A by the environmental condition of plant growth, ripening and storage of seed.