14 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



As early as 1873 Godlewsky " maintained that the form of etiolated 

 leaves was not due to lack of nutrition, and as will be shown later, 

 he consistently progressed in the development of a theory of etiola- 

 tion as an adaptation. 



Detmer*^ investigated the influence of varying intensities of light 

 upon the elongation, turgidity and composition of etiolated shoots. 

 The amount of elongation shown by stems was found to increase 

 with the diminishing intensity of illumination, and was ascribed to 

 the " great turgor extension of the cells," while the expansion of 

 the leaves decreased under the same circumstances. The percentage 

 of dry matter in shoots was lessened as the intensity of the illumina- 

 tion diminished. 



In a later research it was observed that etiolated seedlingrs of 

 Ciiciirbita held the cot3'ledons in an erect position with the inner 

 surfaces appressed. An exposure to light would bring these organs 

 down to the normal horizontal position. As a result of this and 

 similar observations Detmer concluded that light directly affected 

 the relative rapidity of growth of the sides of a dorsiventral organ, 

 and he used the terms ^hoto-epinasty and photo- hyponasty to desig- 

 nate such relation. ^^ 



Lasareff ^^ believed he had established a correlation between the 

 length of the stem and the extent of the root-system in etiolated 

 plants in confirmation of some results obtained by Famintzin. The 

 total length of the roots of a number of common forms decreased as 

 the length of the stem increased, in etiolated series, and secondary 

 roots were shorter and fewer. 



Strehl *^ made a series of measurements of the roots and hypo- 

 cotyls of Ltipimts albtis, by which it appeared that those grown in 

 darkness attained much greater lengths than those under ordinary 



^■^ Godlewsky, E. Abhangigkeit der Starkebildung in den Chlorophyllkornern von 

 den Kohlensauregehalt der Luft. Flora, 56 : 378. 1873. 



^'^ Detmer, W. Ueber den Einfluss verschiedener Lichtintensitaten auf die Entwick- 

 elung einiger Pflanzen. Landw. Versuchss. 16: 205. 1873. See also Detmer, Prac- 

 tical Plant Physiology. Pp. 404-411. 1898, and Detmer, Vergleichende Physiologic 

 d. Keimungsprocesses d. Samen. 18S0. 



■** Detmer, W. Ueber Photoepinastie der Blatter. Bot. Zeitung. 40: 787. 

 18S2. 



*^ Lasareff, N. Ueber die Wirkung des Etiolirens auf die Form der Stengel. Beil. 

 z. ProtocoU d. 45th Sitzung. d. Naturf. Ges. a. d. Univ. z. Kasan. Abstract in Bot. 

 Jahresber. 2 : 775. 1874. 



^^ Strehl, R. Untersuchungen iiber das Langenwachstum der Wurzel und des 

 hypokotylen Glied. 1874. 



