ig2i] PACK—JUNIPERUS 57 



open and the hypocotyls are \ in. long, the seedlings are trans- 

 ferred to pans or beds of leaf mold and sand kept at 15 C. (6o° F.). 

 In no case should ungerminated seeds (seeds that have not split 

 open and developed a short hypocotyl) be transferred from the 

 germinator at 5 C. (4i°F.). The germinated seeds, after being 

 transferred to beds or pans, should be protected by glass plates 

 and paper for the first few days. 



Although these seeds have been germinating during every 

 month of the year, advantage can be taken of the temperature con 

 ditions by placing them in the germinator about January. The 

 importance of this after-ripening and germination at 5 C. cannot 

 be overemphasized. 



Summary 



1. The germination of non-after-ripened juniper seeds under 

 ordinary conditions is very low, amounting to 1 per cent. 



2. These seeds are protected by a semipermeable and thick 

 coat which makes up 75 per cent by weight of the entire seed. 

 Acids enter very slowly, while bases, silver and mercury salts 

 enter rapidly. While the coat serves as a protection against 

 fungal attack and prevents water-imbibed seeds from expanding 

 and rupturing the tissues before after-ripening is accomplished, it 

 takes little or no part in the dormancy or after-ripening of the 

 seed. 



3. Food material in the resting seed is stored in the form of 

 ats and proteins, with traces of glucose but no starch. The rest- 

 ing seed endosperm has a P H value of about 5, while that of the 

 embryo is about 8. 



4. Although some forcing agents changed the respiration and 

 catalase activity of seeds, it was not possible to force the germina 

 tion of non-after-ripening juniper seeds by high temperature, 

 alternating temperature, wounding, warm bath, dry air, removal of 

 coats, treatment with hydrogen peroxide, mercuric chloride, ether, 

 carbon dioxide, oxygen, light, soil, dilute acids, dilute bases, nitrates, 

 suphates, or strong acids. 



5. Freezing and thawing as such has no forcing action on the 

 germination of juniper seeds, neither does it hasten after-ripening. 

 Freezing and thawing produces marked chemical changes in this 



