A large number of substances containing the indole ring are known to occur in plants, some of them having striking effects on the processes of growth (cfl RUttLAND 1961). It is however somewhat difficult at present to distinguish clearly between "flee" and "bound" indoles.In a previous paper (TANDLER 1962) we reported in the giant unicellular green alga Acetabularia the presence of intracellu]ar crystals whose indote nature was indicated by intense Ehrlich and Salkowski positive reactions. Alkaline hydrolysis of ethanol-extracted algae liberated, besides tryptophane, substantial amounts of Salkowski-positive indolcs.It is the purpose of the present paper to study further (A) the nature of the indoles released by hydrolysis and (B) the chemical and cytological properties of the Acetabularia crystals.
A. Chromatographic analysis
Material and MethodsThe algae, Acetabularia crenulata and A. mediterranea, were cultured in ': Erdschreiber" medium (H~i~EaL~G 1944; BET~ 1953). The celIs (3--6 cm long, with and without caps) were killed by immersion in Carnoy's ethanol:chloroform: acetic acid, 6:3:1 (v/v) mixture for 3 h and extracted for at least 3 weeks with 96 and 80% ethanol, all steps being carried out at 2~~ in darkness. Chromatography. Using Whatman paper No 1, ]inear and two-dimensional (ascending) chromatograms were obtained. The solvents used were: isopropanol-25 % ammonia-water = 8:1 : 1 (S~N and LEOeOLD 1954), isopropanol--glacial acetic acid-water ~ 4:1:1 (KAeER and VELDSTRA 1958) and distilled water. The spots were developed by spraying with the reagents according to EI-IRLICH (660 mg of p-dimethylaminobenzaldehyde dissolved in a mixture of 36 ml of ethanol and 8 ml cone. HCl) (KA])EI~ and V]~LDSTRA 1958) or SALKOWSXI (0.02 MFeC13 in 20% HC104); a more diluted reagent is 5 % HC104--0.05 M FeC] 3 = 50:1. The Ehrlieh reagent was employed in the following manner: after spraying, the chromatogram is left for 5--15 rain at room temperature (~220C) and then is heated at 60~ for another 5--15 min.
