PRINGSHEIM^S RESEARCHES ON CHLOROPHYLL. 



123 



substances deposited therein. It is the primary product 

 of the reduction-process, and is the basis of all the ternary 

 compounds in the corpuscles. 



Further experimental proof of this is found in the formation 

 of hypochlorin in young seedling plants under the influence of 

 light. Seedlings of angiosperms grown entirely in the dark 

 are not green and have no hypochlorin. The duration of 

 culture in darkness matters not. Hypochlorin cannot be 

 formed in this instance out of the reserve materials in the 

 plant, and therefore, even if seedlings grow in darkness until 

 all the reserve material is used up, no hypochlorin is formed. 

 Light is necessary for its production, and that, too, of a 

 greater intensity than is necessary for development of green 

 colour in the seedling. Both the hypochlorin and the 

 chlorophyll colouring matter only arise if the seedling when 

 still developing is placed in light, and the hypochlorin 

 appears later than the chlorophyll colouring matter, and 

 after a longer exposure to the light. 



Seedlings of such plants as peas, hemp, cucumber, flax, 

 &c., which, after being grown for eight days in the dark 

 are still capable of becoming green and of developing, if 

 exposed in a temperature of 20° to 23° C. (in July and August), 

 to a bright diff'use daylight, become plainly green in two to 

 three hours, and in six to ten hours are very deep green, 

 but only after some nineteen or twenty hours of exposure 

 are traces of hypochlorin found.i Hypochlorin in seed- 

 lings of angiosperms is thus only formed under the 

 influence of light, and as a consequence of assimilation, 



' Table showing relative time of appearance of Hypochlorin and Chlorophyll 

 in Seedlings of Angiosperms grown in the Bark, and the dependence of 

 Hypochlorin upon Light. The experiments were made upon seedlings 

 of peas, hemp, cucumbers, flax, and other plants, all from seeds sown at 

 same time. 



* In Cucurbita the cotyledons were, as is often the case in this plant, 

 bright green. 



