Wuchsstoffe und Hemmstoffe der Haferkoleoptile 



2. The water difTusate from the apices contained the active substance 

 indoleacetic acid, a second growth-promoting substance and two growth- 

 inhibiting substances. Table 2 shows the i^^^-vahies of these substances 

 (descending method). An inactive precursor was also found in this diffusate. 

 This became active when treated with acid. 



Table 2 



Proportions: v/v. Ammonia = 25 per cent NHj. 



3. The diffusate, when made alkaUne and shaken with chloroform, 

 yielded a possibly different inactive precursor. During the development of 

 the chromatogram this gave rise to the same two growth-promoting substances 

 as were obtained in the water diffusate. f 



4. The chromatogram developed from the inactive growth substances 

 moving from the seed to the apex of the coleoptile showed two active 

 substances : indoleacetic acid and a growth-inhibiting substance. The lAA 

 must be formed during the chromatographic preparations. 



LITERATUR 



BoNDE, E. K. (1953). Auxin and auxin precursors in acid and nonacid fractions of 



plant extracts. Bot. Gaz. 115, 1. 

 Larsen, p. (1944). 3-indole acetaldehyde as a growth hormone in higher plants. 



Dansk bot. Ark. 11, 1. 

 Raadts, E. (1952). tJber den inaktiven Wuchsstoff der Haferkoleoptile. Platita, 



40,419. 

 Reinert, J. (1950). tJber den Wuchstoffgehalt der Avena-Koleoptilen-Spitze und 



die chemischen Natur des extrahierbaren Auxins. <^. JVaturf. 5B, 374. 

 SoDiNG, H., and Raadts, E. (1953). Uber das Verhalten des Wuchstoffes der 



Koleoptilenspitze gegen Saure und Lauge. Planta, 43, 25. 

 Stowe, B. B., and Thimann, K. V. (1954). The paper chromatography of indole 



compounds and some indole-containing auxins of plant tissues. Arch. Biochem. 



Biophys. 51, 499. 



t From the results of further experiments, it is doubtful whether the second growth 

 substance of the raw diffusate and the second growth substance of the alkaline shaking are 

 identical. 



55 



