Seed Geometric Morphometrics of Neottioid Orchids

Abstract

This study aims to investigate orchid seed variation between some representatives of Neottieae, C. rubra, L. abortivum, Neottia nidus-avis, and N. (Listera) ovata, naturally distributed in our country by using geometric morphometric analyses based on 2-dimensional landmarks. For this purpose, a total of 95 specimens were evaluated. The results of ANOVA, PCA, and discriminant analyses showed significant shape and size differences between the species. Size differences were statically significant among all species except for that between C. rubra and N. ovata. Based on PCA, shape differences were most prominent in the chalazal and micropylar regions of the seed as well as the whole seed width. Discriminant analysis was also statistically significant and cross-validation scores were a highly powerful to distinguish the species with scores ranging from 60% to 88%. Regression analyses also showed highly significant allometric effect of the size on shape with a similar trend across species. Based on current results, geometric morphometric analysis is promising in the study of morphological variation within plant parts. The present study is also significant in terms of the widespread use of such studies in the field of botany, especially in the context of systematic or functional morphology.