i9*>] CL'RREXT LITERATURE 245 



turbances. In blue violet they were more vigorous and deep green. In 

 short, the green lettuce showed a deficiency in chlorophyll development in yel- 

 low and green lights. Some other irregularities appeared in certain other plants. 



The blooming was earlier (green lettuce, Fuchsia, beans, tomatoes) as one 

 passed from bed I to IV; that is, the euphos glass, which cut out much of the 

 ultra violet rays, favored early blooming to a marked degree. The number of 

 fruits increased from bed I to IV. In red, yellow, green, and blue violet the 

 blooming was deferred and the number of fruits reduced. 



The ultra violet rays have a very important relation to anthocyanin 

 development in the epidermal layer. In red-leaved lettuce the red color fell 

 as one passed from bed I to bed III where no red developed. No anthocyanin 

 developed in beds IV to VIII. Celosia Thomson*, red-leaved begonia, and red- 

 leaved beet acted similarly, except that anthocyanin developed in the midribs 

 and petioles of the last in all the beds. When any of these plants were grown in 

 beds where anthocyanin did not develop, and were then transferred to bed I, 

 anthocyanin began to appear in 2 days and was fully developed in 8 days. 

 When plants grown in bed I and bearing anthocyanin were transferred to 

 beds III to VIII, the new leaves unfolding in the latter beds were without 

 anthocyanin. 



In all plants except one Schanz found no evidence that the red pigment 

 functioned in protecting the plant against the injurious action of the ultra 

 violet of the solar spectrum; for when plants were transferred from bed IV, 

 where no red pigment developed, to bed I, no injury appeared, but the leaves 

 soon developed the pigment. Red beech was the exception. When this 

 plant was transferred from bed IV to bed I, the old leaves without pigment 

 died within a few days, and the new leaves unfolding developed the red pigment. 



The rate and percentage of germination of seeds (lettuce and stinging 

 nettle) increased from bed I to bed IV. Repeated cultures on these forms 

 showed that ultra violet interferes with germination. 



When etiolated seedlings (bush beans, soy beans, potatoes) were trans- 

 ferred to the beds, the order of greening, beginning with the fastest, was red, 

 euphos b, euphos <z, ordinary glass, open bed, yellow, green, blue violet. The 

 development of chlorophyll is favored by a greater and greater removal of 

 the ultra violet. Also chlorophyll decomposition is deferred in old plants by 

 screening out the ultra violet rays. 



Schanz mentions the fact that in Holland many growers prefer crudr 

 glass to regular window glass for forcing houses. He finds that crude glass 

 cuts out more of all rays than window glass, but that it is especially effective 

 in screening out ultra violet, and concludes that any possible detrimental 

 effect from reducing light intensity for synthesis is more than counteracted 

 by the benefits derived from screening out injurious ultra violet rays. 



From these results it seems evident that Schanz was fully justified in his 

 earlier statement that ultra violet light of the solar spectrum has a remarkable 

 effect on the development of plants. 



