Abstract (eng)
Mosses are the first land plants and therefore differ from algae and they are evolutionary separated from the vascular plants. In comparison to the vascular plants, the gametophytic plant is dominant in mosses. This gametophyte can be easily investigated and because of its haploidy, genetic modifications are easily done. For Physcomitrella patens are GFP cell lines available; these can be used to study some subcellular structures with confocal microscopy, as done in the present work.
The aim of this study was to analyse the subcellular structures in P. patens, how they look like and how they respond to osmotic stress meaning that those strands contain ER, actin and tubulin.
The Endoplasmic reticulum (ER) cell line showed the ER near the plasma membrane; this was proven by labelling with the styryl dyes FM 1-43 and FM 4-64. Furthermore, the nuclear envelope and the dynamic network of cisternae and tubules formed by the ER were seen. Under osmotic stress, the cisternae were aggregating and getting fewer.
The Life-act cell line showed the actin in the cortex of the cell, around the nucleus and a network between chloroplasts. Unfortunately, labelling the actin filaments with the Rhodamine phalloidin did not work in living cells. During plasmolysis, the actin filaments formed ring structures near the chloroplasts and enclosed them within the actinfilaments.
The GFP-Tub cell line showed that the microtubules enclosed the chloroplasts within the microtubules. Furthermore, it was also shown in close vicinity to the plasma membrane and around the nucleus. Under plasmolysis the tubulin was aggregating around the chloroplasts and formed rings around them.
The Myosin VIII, Reticulon and Calnexin cell lines did not show the structures known from literature.
When plasmolysed, the cell lines of ER, Life-act and GFP-Tub of P. patens showed in the leaflets and protonemata the Hechtian strands.
A DVD with movies of time lapses of pictures of the subcellular strucures is attached to the present work.