The population of Datura stramonium L. var. tatula Torr and Datura wrightii Regel was heterogenous in the numerical and structural composition of karyotypes. Datura wrightii Regel contained, as well as aneuploid sets, a 35% karyotype with a diploid set of chromosomes (2n = 24); there were no chromosomes with satellites and there were 1-2 microchromosomes in 29.6% of the metaphases. Datura stramonium L. var. tatula Torr included biotypes with a chromosome number of 21-25; in 88.5% of the metaphases there were chromosomes with satellites and 60% of the metaphases contained 1-3 microchromosomes. According to the content of the main alkaloids Datura stramonium L. var. tatula Torr can be considered a predominantly hyoscyamine type, Datura wrightii Regel also containing scopolamine.

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A precise and simple method for the quantitative estimation of Na,K-ATPase activity is based on the uptake of 1°Rb into human erythrocytes in vitro (6). We used this method in 5 experiments to compare the inhibitory effects of Coronilla glycosides with those of ouabain and digitoxin. The results were evaluated by non-linear regression analysis and expressed as LC51 SE (Fig.2). RE OH 1 t HYE P -O-fl-D-g1ucolyraeosyi-I3-D -ytOpyraflOSyt 2 DRY) P /7 -D-xytopyranosy) Fig. 1 Structures of hyrcanoside (1) and deglucohyrcanoside (2). 467Coronilla z'aria L. (Fabaceae) (Crownvetch) is a perennial plant widely spread in Europe and cultivated in the U.S.A. From the seeds, the glycosides hyrcanoside (1; HY) and deglucohyrcanoside (2; DHY) ( Fig. 1) were isolated by Russian (1) (from a not exactly defined taxon) and American workers (2. 3) (from the cv. Penngift). Only the antineoplastic effect of these substances has been studied so far (2, 3). We have, therefore, isolated these substances from the seeds of the taxon growing in Bohemia (4) in order to study their biological activities in more detail.Since the glycosides under investigation are steroids with a lactone ring in the molecule, their possible cardiotonic properties were examined. The inhibition of Na, K-ATPase is the basis for the cardiotonic activity of cardiac glycosides (5). We have, therefore, studied the Nat. KtATPase inhibitory activity of Coronilla glycosides. \0 0 z 0 Iz [JrY 3,80 0,50 tI.J 3,07 0,27Both Coronilla glycosides showed remarkable Na, K-ATPase inhibitory activity increasing in the range iO to 1O"'mol, 1_I. Their activities lie between those of ouabain and dixitoxin, DEW being slightly more active than FlY.Other substances isolated from Crownvetch and studied (daphnoretin, scopoletin, umbelliferone, and epicatechin) neither showed an effect on ATPase activity nor did they interfere with the inhibitory effect of the glycosides (data not shown). Fig. 2 Inhibition of Na', K'-ATPase by digitoxin (.DT), hyrcanoside (0 HY)), deglucohyrcanoside (SDNY), and ouabain (x OU). H3 0 CH I 80 20 1C50± SE ( _8 nul . 1) * Dl 9,15 1,27 o HY 4,680,76 . 0,01 0,1 CONCENTRATION io6 mol . 1 2 Downloaded by: University of Arizona Library. Copyrighted material.

Between 1986 and 1989 we studied the influence of T-irradiation (2.5 -80 Gy) on growth processes and the content of arbutin glycoside. Bearberry [Arctostaphylos uva-ursi (L.) Sprengel] shows polycyclic characteristics of growth; the vegetation period is divided by summer dormancy (June) into periods of spring and summer growth. As plants age the summer dormancy gets longer and the period of summer growth is shorter. Irradiation with a dose of 80 Gy was lethal and a dose of 60 Gy damaged plants so much that they were not able to grow in the first spring after irradiation. Significant growth stimulation (both in the height of plants and in branching) was shown only in the second year after irradiation (2.5 -60 Gy). In the fourth year the growth in all irradiated variants was weaker than in the control. Doses of 2.5 and 5 Gy did not influence the content of arbutin significantly; higher doses of irradiation changed the dynamics of production and decomposition which is connected with growth changes.

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