Anatomical, micromorphological and karyological contributions to the Periploca graeca (Apocynaceae) taxon

Öz

Periploca graeca L. (Garipler urganı) is currently treated as a species-level taxon without any infraspecific taxa in modern classifications. In this study, comprehensive stem and leaf anatomy and micromorphology, and somatic chromosome number of P. graeca taxa, collected from different populations in Türkiye, were examined comparatively, for the first time, using light microscopy and Scanning Electron Microscopy (SEM). In anatomical examinations, stems contained numerous groups of small, thick-walled cortical sclerenchymatic fibers; bifacial and hypostomatic leaves included anomocytic and parasitic stomata; and bicollateral vascular bundles, druse crystals, and laticifers were found throughout stems and leaves. In SEM examinations, stems were glabrous, petiole and lamina surfaces were covered with densely villous indumenta, or relatively glabrous, and epicuticular wax layer was rough on the stem and petiole, and radially striated on the leaf blade. Non-articulated laticifers, located throughout the midrib, petiole and stem, and “colleters”, known as glandular hairs located at the base of the petiole (defined as the standard type), were determined as the two main glandular structures. The somatic chromosome number was determined as 2n = 22 for the both populations. Parametric and non-parametric analyses indicated that population-level variation in P. graeca was mainly associated with differences in tissue dimensions of stem (periderm, collenchyma, cortex and vascular bundles) and mesophyll (palisade and spongy), and size and density of epidermal cells and stomata. Although some characters showed statistically significant differences, the overall anatomical, micromorphological and karyological similarity between the populations suggests that these differences are related to environmental variation rather than taxonomic differentiation.

Anahtar Kelimeler

• Chromosome number
• anatomy
• leaf
• micromorphology
• stem

Periploca graeca (Apocynaceae) taksonuna ilişkin anatomik, mikromorfolojik ve karyolojik katkılar

Öz

Periploca graeca L. (Gariplerurganı), modern sınıflandırmalarda herhangi bir tür altı takson içermeyen, tür düzeyinde ele alınan bir takson olarak kabul edilmektedir. Bu araştırmada Türkiye’deki farklı popülasyonlardan toplanan P. graeca taksonlarının kapsamlı gövde ve yaprak anatomisi ve mikromorfolojisi ile somatik kromozom sayısı ışık mikroskobu ve Taramalı Elektron Mikroskobu (SEM) kullanarak ilk kez karşılaştırmalı olarak incelenmiştir. Anatomik incelemeler, gövdelerde korteks boyunca çok sayıda küçük kalın duvarlı sklerenkimatik lif gruplarının bulunduğunu, bifasiyal ve hipostomatik tipteki yaprakların anomositik ve parasitik stomalar içerdiğini, gövde ve yaprak boyunca bikollateral iletim demetleri, druz kristalleri ve latisiferlerin bulunduğunu göstermiştir. SEM incelemelerinde, gövdelerin tüysüz olduğu, yaprak sapı ve yaprak yüzeylerinin yoğun villoz tüy örtüsü ile kaplı olduğu, ya da nispeten tüysüz, epikutikular mum tabakasının gövde ye yaprak sapında pürüzlü yaprak ayasında ise radyal çizgili olduğu tespit edilmiştir. Ortadamar, yaprak sapı ve gövde boyunca yer alan eklemsiz latisiferler ile yaprak sapının tabanında konumlanan ve salgı tüyü olarak bilinen “colleterler” (standart tip olarak tanımlanan) iki önemli salgı yapısı olarak tespit edildi. İncelenen her iki populasyon için somatik kromozom sayısı 2n = 22 olarak belirlenmiştir. Parametrik ve parametrik olmayan analizler, P. graeca'daki popülasyon düzeyindeki varyasyonun esas olarak gövde (periderm, kollenkima, korteks ve iletim demetleri) ve mezofil (palisad ve sünger) dokularının boyutlarındaki ve epidermal hücrelerin ve stomaların boyut ve yoğunluğundaki farklılıklarla ilişkili olduğunu göstermiştir. Bazı karakterler istatistiksel olarak anlamlı farklılıklar gösterse de, popülasyonlar arasındaki genel anatomik, mikromorfolojik ve karyolojik benzerlik, bu farklılıkların taksonomik farklılaşmadan ziyade çevresel varyasyonla ilgili olduğunu işaret etmektedir.

Anahtar Kelimeler

• Kromozom sayısı
• Anatomi
• yaprak
• mikromorfoloji
• gövde

Kaynakça

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