Chemical Conditions in Maturation, Dormancy, and Germination of Seeds of Gymnocladus dioica

In Gymnocladus dioica the impervious seed coat is closely associated with the physical phenomenon of uniform shrinking. 2. The inner pod material, which in the nearly mature pod forms a gumlike mass, plays a part in insuring a slow uniform drying of the seed. 3. Tests indicate that from a chemical standpoint insoluble pectic materials may play a big part in water exclusion by the Malpighian layer. 4. In the present uncertain state of knowledge concerning the composition of the pectic materials, it is not possible to tell whether chemical changes in the Malpighian layer accompany shrinking in the final stages of rapid water loss when the seed becomes impervious. 5. Starch is abundant in the cotyledons in the immature stages and during germination. 6. In the cotyledons the maximum oil content is reached at maturity; at that time the starch content reaches a minimum. 7. Non-reducing sugar is an important storage form in the seed. 8. Reducing sugars are absent in the mature seed, but are found in small quantities in the immature and the germinating stages.