Pigments and ultrastructural peculiaries of cell organelles of fern Polystichum aculeatum (L.) Roth. at different stages of development

Abstract

Qualitative and quantitative content of photosynthetic pigments in fronds of P aculeatum sporophyte at different stages of ontogeny was determined. The maximum content of photosynthetic pigments was registered at the stages of spore fructification and winter vegetation. A specific feature of fronds of P. aculeatum sporophyte is a relatively high content of carotenoids. At the stage of sori formation (May–June) mesophyllous cells of P. aculeatum fronds contained chloroplasts of rounded and elongated lenticular shape. Rounded chloroplasts stroma and grana, formed with small number of thylakoids are relatively electron-loose. The lenticular chloroplasts with electron-dense stroma and grana fill their volume. These chloroplasts contain large starch grains and occasionally plastoglobules. The ultrastructural differentiation of chloroplasts was not associated with certain anatomical areas of fronds. In May, chloroplasts in mesophyllous cells are located close to the plasmalemma. The ultrastructural ordering of the inner membrane system of parenchymal chloroplasts of P. aculeatum fronds were affected by seasonal temperature variation and changes in the lighting conditions. At the stage of autumn vegetation in the chloroplasts of mesophyllous cells there are sometimes formed neoplasms. A partial destruction of their internal membrane system and emergence of numerous plastoglobules were observed. The number of starch granules in the plastids was significantly reduced. Parenchyma cells of P. aculeatum rootstock had a significant amount of amyloplasts both in spring, at the stage of sori formation, and at the stage of autumn vegetation. These organelles were densely filled with starch grains while a developed internal membrane system was practically missing. The absence of significant changes in their ultrastructure is primarily associated with the optimal conditions for P. aculeatum (area of the ferns in Acad. O. V. Fomin Botanical Garden of Taras Shevchenko Kyiv National University).

Keywords

• Polystichum aculeatum (L.) Roth.
• ontogeny
• pigments
• chloroplasts
• ultrastructure