Micromorphological and anatomical studies on the tribe gentianeae (gentianaceae) in Türkiye

This thesis examines 19 taxa from 4 genera of the Gentianeae tribe in Türkiye using micromorphological and anatomical methods. Light and electron microscope images were used in the studies. Statistical analyses (PCA, clustering, t-test, Mann-Whitney U test) were performed to assess the taxonomic value of the characters and to understand relationships among taxa. Pollen grains were monad, radially symmetrical, isopolar, and tricolporate. Their shapes were mainly oblate-spheroidal, with some subprolate and prolate-spheroidal forms. Ornamentation was mostly striate-perforate or striate-reticulate, with occasional striate, rugulate, or rugulate-perforate types. The seed surface morphology is generally observed as reticulate, and occasionally as rugose or striate. Through PCA conducted on the palynological characteristics of the Gentiana genus, 84,2% of the total variance was explained. Three principal component groups were identified: PC1 (equatorial axis, Clt, pore length, pore diameter, mesocolpium, apocolpium), PC2 (polar axis, Clg, P/E), and PC3 (exine, intine, Clg/Clt). Additionally, three groups were formed based on cluster analysis of palynological characteristics. Anatomical and palynological groupings show differences. The palynological characteristics are important because they show similarities with the systematic classifications in previous studies (G. gelida and G. boissieri, G. pyrenaica and G. aquatica, the subspecies of G. verna). Anatomical and palynological cluster analyses of the Gentianella genus show similarity. In Swertia, two taxa differ significantly in certain palynological (polar axis, Clg, Clg/Clt, apocolpium, exine) and anatomical (vascular bundle thickness, trachea diameter, cortex parenchyma diameter, stem epidermis length, leaf width, mesophyll thickness, leaf xylem diameter, upper and lower epidermis length) traits.