THE HORTICULTURAL SOCIETY OF NEW YORK 



Professor R. B. Harvey, University of Minnesota, in his paper, 

 "Carbohydrate Production and Grov^th in Plants Under Artificial 

 Light," 1923, gives the most interesting results of his analysis. 

 The following extracts are quoted from Professor Harvey's pa- 

 per : 



"We have made chemical analysis of the carbohydrates produced 

 in plants at the various light intensities. The effect of continuous 

 illumination is to cause the accumulation of large quantities of 

 starch in the plants. Wheat grown in artificial light is full of 

 starch. Buckwheat has so much starch that the grains may be 

 easily pulverized in the hand. 



"Nasturtiums produced in continuous artificial light are full of 

 sugars so that the flowers keep for a longer time than flowers cut 

 from plants grown outdoors. Cabbage leaves were found to con- 

 tain one-third of their dry weight as starch and sufficient other 

 easily hydrolysable carbohydrates to raise the quantity estimated as 

 starch by the method of acid hydrolysis to 53 per cent, in one case. 

 This is a much greater quantity of starch than found in green 

 leaves grown in sunlight. In alternating day and night the quan- 

 tity of carbohydrates in the leaf shows a periodic fluctuation cor- 

 responding to the period during which photosynthesis can occur. 

 Growth also is fluctuating in its rate. When the light is continu- 

 ous, photosynthesis is not stopped as in a period of darkness, and 

 growth is uniform in rate. 



TOO EXPENSIVE FOR VEGETABLES 



"I do not believe that artificial light will be used in the near 

 future for the growth of crop plants on a commercial basis. Yet 

 I do believe that many rare and valuable flowers may be grown 

 for the market out of their regular season by the use of electric 

 light. Orchids and Water Lilies are most valuable when they 

 cannot be supplied from cultivation in ordinary daylight. The 

 use of artificial light will make the production of such plants pos- 

 sible at times when there is no competition. The best application 

 of the method lies in the aid to plant breeders in hybridizing 

 plants and in growing the progeny to maturity out of season and 

 in a short time." 



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