Morphological Variations in Caryopses and Seedlings of Two Grass Species of the Genus Dactyloctenium Willd.

Abstract

Dactyloctenium aegyptium (L.) Willd. and D. aristatum Link. are common grass weeds of cultivated fields in many crops. The two grass weed species growing under same habitat showed characteristic morphological differences of caryopses and seedlings. The identification of weeds at seedling stage may be useful in weed and environment management. Under the light microscopy, features like colour, base, surface, scutellum and hilum of caryopses showed differences between the studied species. D. aegyptium had dark brown caryopses colour, while D. aristatum had grey colour. The base of D. aegyptium was truncate, while D. aristatumhad obtuse base. Both species had rugose surface but in D. aegyptium surface undulations were closely spaced whereas in D. Aristatum it was widely spaced. Similarly seedlings were found distinct with respect to coleoptile shape and size, first leaf sheath surface and first leaf blade shape and surface. D. aegyptium had oblong coleoptile whereas it was obovate in D. aristatum. The leaf sheath and leaf blade were recorded glabrous and hairy in D. aegyptium and in D. aristatum respectively. Both species studied hereby, showed remarkable differentiations in their characters, thus indicating that the morphological attributes of caryopses and seedling can be exploited taxonomically and for crop and weed management.