Comparative anatomical study of the spikelet Pedicels of selected species of different Tribes belonging to the Poaceae family in Iraq

Abstract

The current study is a comparative anatomical study of species of the Poaceae family growing in different regions of Iraq, namely Ammochloa palaestina Boiss., Schismus barbatus Thell., Schismus arabica Nees., Arundo donax L., and Cymbopogon bakeri cont. The anatomical study included the anatomy of the spikelet. The results of the current study showed that the anatomical features are of great taxonomic importance and help in isolation and diagnosis, through the many variations shown by the anatomical characteristics of the studied species. The spikelet pedicels showed important anatomical characteristics in terms of the epidermis, as the species were similar in terms of thickness and rippling of the epidermis, with the exception of A.palaestina, whose epidermal cells were of medium thickness, and A.donax, which was straigh Spiklete pedicels were characterized by the presence of stomata, as the stomata differed in their dimensions, numbers, and shapes, in addition to their arrangement, which was considered an important characteristic in isolation and diagnosis. The stomata are also organized in such a way that only one long cell separates one stomata from another and has been recorded in the species S. arabica except for the species A.donax, S. barbatus, A.Palaestina and C. bakeri, where two long cells separate between them, separated by one short cell or more than two cells. The epidermis also varied in the shapes, numbers and distribution of short cells, as the type S. barbatus was unique in not containing cork cells associated with a silica cell compared with other species, while the two types C. pakeri and A.donax were unique in containing only cork cells associated with a silica cell paired with another pair of cells, which was considered an important taxonomic characteristic. The surface cover of the epidermis of the alveoli was represented by only one type, which is thorns. The thorns varied in size between medium and large, and were characterized by their elongated oval base. The thorns were generally distributed between and between the veins, and this characteristic did not show any difference between the studied species except for the type A. palaestina, which Unique not to contain thorns. All these characteristics contributed to the addition of distinctive characteristics to each species, important in isolating and diagnosing it.