Preliminary considerations on the external morphology Plantago major L. leaves from natural populations exposed to different environmental conditions

Abstract

Background and purpose: Allometry is the study of the relationship of body size to shape, anatomy, physiology and behavior. Plants displaying allometric relationships between certain traits across different environments should have higher relative fitness then plants lacking these allometric relationships. We hypothesized that there are differences in external morphology between Plantago major L. (ssp. major) leaves exposed to different environmental conditions with variations for the leaf characters analysed.

Materials and methods: Seven, linear dimensions on each leaf: leafblade apical width (AW), leaf-blade length (LL), leaf size (LS), leaf width (LW), leaf shape (LW/LL), the distance from the midrib to the neighboring vein (MV) and vein distances within a leaf (VD) were analysed. Here, besides analyzing allometric relationships between the common plantain leaves exposed to different environmental conditions, morphological data were also used for a regression analysis and for a cluster analysis.

Results: In the reference area (Vinci village) leaves have significantly longer LL and they are significantly broader compared with leaves from polluted site (Pančevo). At both sites, LL decreased relatively to LS (i.e. negative allometry is character specific). This study also revealed that VD and LW/LL are developmentally and functionally integrated P. major leaf characters. Moreover, VD is under more selective pressure to adapt to current environmental conditions than LW/LL.

Conclusions: Obtained data showed that leaf size is significantly related to both, developmental and environmental conditions. This indicates that plant species such as Plantago major L. (ssp. major) should be considered as reliable bioindicators in environmental quality monitoring studies.