New traits to differentiate Datura Ferox and D. Stramonium Seeds (SOLANACEAE)

Abstract

Three species of Datura grow in Argentina: D. ferox L., D. inoxia Mill., and D. stramonium L. However, only Datura ferox and D. stramonium are toxic weeds and usually contaminate seed lots used as food, such as corn, sunflower, sorghum and soybeans. A correct identification of these two species is of great importance, both for the purity of the grains harvested in the country and those of interchange. At the present, the differentiation of the two species of “daturas” is made by using the seed size, however, this feature alone is not enough, because of the variability existent in different samples. Therefore, the objectives were: to deepen the knowledge of the seminal tegument structure, and to establish the significance degree from the differences found. To perform the anatomy study, conventional microscopy techniques were applied. The main features of differentiation were: the sclereids of exotesta in D. ferox presented length and width significantly higher than D. stramonium, and also, in surface view showed thicker cell walls with few and rounded lobes and sinus less deep than D. stramonium. For the contrary, the endotesta cell size was significantly higher than in D. stramonium than in D. ferox.