Crystal macropatterns in vegetative and reproductive organs of Trifolium species

Abstract

Crystals are widely distributed in many plant species, some of them being specific for certain taxa. An investigation of type, composition and distribution of crystals in vegetative and reproductive organs of twenty Trifolium L. species was carried out using Light and Scanning Electron Microscopy and Energy Dispersive Spectroscopy. Solitary, prismatic calcium oxalate crystals, variable in size and number, were present in all examined plant parts. They were distributed in parenchyma sheath cells along the vascular bundles of lamina, main vein, stipules and calyx and above sclerenchyma groups by phloem in petiole, stem and peduncle. In stipules and calyx they were also present in one layer of mesophyll cells. From taxo-nomical point of view, the type and distribution of crystals were not valuable characters in distinguishing species of this genus or taxa of infraspecific rank. They might be more useful at the level of genus or even family. Crystals are less numerous, or even absent in organs of forage Trifolium species, which probably also contributes to their higher digestibility and forage quality.