Germination of Forest Trees Ji 



In the case of one and the same species large, heavy seed are better than 

 light ones. The former generally possess a greater power of germination 

 and the resulting seedlings show a greater power of resistance against 

 injurious external influences and a more vigorous development which in 

 many species is due to the greater quantity of reserve food materials 

 deposited in the seed. This superiority at the first start should not be 

 underestimated because it is recognizable long after the seedling stage 

 has been passed. In many cases the dominant trees grow out of the seed- 

 lings which had the better start. 



The relation of size and weight of seed to germination per 

 cent, and later development has been worked out to a much 

 greater degree of certainty in the case of agricultural and garden 

 seeds than in the case of forest-tree seeds. These facts have 

 already been quite firmly established in practice and already 

 adopted as a criterion of seed values. There is no reason why 

 weight of seed should not play as important a part in selecting 

 forest tree seeds as well as agricultural and garden seeds in the 

 future, as the source and germination per cent, of those seeds. 



A considerable amount of work has been done by investigators 

 upon cereals, regarding the comparative value of heavy and light 

 seed used in planting. Most of the work has been done with 

 wheat, oats, and barley and the preponderance of evidence is in 

 favor of the large seed. The hypothesis upon which this work 

 has been based was the fact that, since the weight and size of the 

 seed determines largely the amount of food material immediately 

 available for the plantlet at the time of germination, it is reason- 

 able to assume that these factors might have some influence upon 

 the life of the plant and even upon the final crop. 



Early experiments by Hellriegel, Wollny, Marek, and others 

 (28) were favorable to the view that seeds of greater size and 

 weight generally give more vigorous plants than those smaller 

 and lighter. Hellriegel was of the opinion that differences at 

 maturity between the product of heavy and light seeds are in- 

 tensified when the conditions are unfavorable. Hicks and 

 Dabney (2S) have made a test of the relative effects of weight 

 upon vigor, using many kinds of seeds. In the case of radish, 

 vetch, sweet pea, cane, Kafir corn, rye, and oats the total weight 

 of the seedlings in each case favored the heavy seed. The differ- 

 ences in germination per cent, of light and heavy seed was not 



