SEEDS: THEIR PRESERVATION AND GERMINATION. 651- 



LOWEST. HIGHEST. MOST RAPID. 



Wheat ....... 41 ° F. 104° F. 84° F. 



Barley 41 104 84 



Pea 44.5 102 84 



Maize 48 115 93 



Scarlet Bean 49 iii 73 



Squash ....... 54 115 93 



Sachs, from extensive experiments with agricultural seeds, concludes that the 

 lowest temperatures at which they will germinate range from 40° to 55°, and the 

 highest from 102° to 116°. 



Goppert found none to germinate below 39°. DeCandolle sprouted mustard 

 ISinapis alba) at less than 32°, and thinks it would have germinated at a still 

 lower temperature had it been possible to keep water around the seed in a liquid 

 form at a temperature of 31.1° or 30.2°. 



Mustard germinated in seventeen days at the lowest degree at which water 

 could be retained in liquid form. The seeds of this plant, germinated at 



35.6° in fifteen days. 39-2° in nine days. 



54° to 68° in two days. 69.8° in one day. 



At 77° in a little over one day; at 82.4° only a small portion of the seeds 

 came up after three days; at 104° none. 



It is said the cocoanut will not germinate readily under about 120° Germi- 

 nation is influenced not only by the degree of heat but also by the uniformity of 

 the temperature. 



In the investigation of the relation of heat to the phenomena of plant-growth 

 Koppen has reached the conclusion that a uniform temperature is more favora- 

 ble to plant-growth than a variable one even though the variable one be a higher 

 one. He concludes that any variation in the temperature is prejudicial to the 

 growth of the germ, and that a low but uniform temperature will result in a more 

 rapid germination than a higher one if subject to variation. A uniform spring 

 temperature with a cloudy sky is, in the opinion of this authority, more condu- 

 cive to rapid development of vegetation than an alternation of hot days and cool 

 nights though the average temperature be the same. Sachs is of the opinion that 

 the degree of temperature at which germination takes place has an important in- 

 fluence on the relative development of the different parts of the plant. A low 

 temperature, according to this observer, is unfavorable to the development of new 

 roots and leaves, but the organs already formed in the embryo are greatly extended ; 

 but under the influence of a high temperature new roots, leaves and buds are 

 rapidly formed even in advance of the complete development of those already 

 existing in the embryo. 



Though not fully understood in all its bearings the question of temperature 

 is recognized as exerting a capital influence on the phenomena of germination. 

 A very important influence also is exerted on germination by the presence of 

 light. 



