Para-crystalline membrane structures resembling prolamellar bodies in the invasion zones of indeterminate root nodules of Vicia faba L.

Novel para-crystalline structures resembling prolamellar bodies in etioplasts were found in the invasion zones of indeterminate root nodules of Vicia faba, which possess persistent meristems and exhibit sequential developmental stages. The para-crystalline structures existed in most cells in the area of the invasion zone and a hexagonal arrangement of tubular membranes was recognized. Extensive membranes, apparently procured from the structures, were often in contact with the bacteria in young infected cells. We propose that the para-crystalline structures serve as a reservoir of membranes for the formation of the numerous symbiosomes that propagate and fill the infected cells, and suggest naming them pro-symbiosome membrane bodies.

The ultrastructure of proplastids in the leaves of five species of Orchids. I. Organization of the inner membrane system and divisions of the proplastids

The ultrastructure of proplastids in the leaves of five species of orchids was investigated: <i>Paphiopedilum, Stanhopea, Cymbidium, Coelogyne</i> and <i>Orchis</i>. The proplastids of the different species differ in the density of their stroma. The most electron dense is the stroma of <i>Paphiopedilum</i> proplastids and the lowest electron-density is shown by <i>Orchis</i> proplastids. A characteristic feature of most of the investigated proplastids is the presence of prolamellar bodies. The frequency of their occurrence and their structure differ from species to species. The remaining membrane system is limited to single peripheral vesicles. Dividing forms of the proplastids have been observed. The number of dividing proplastids averages 5 per cent. The proplastids have been observed to divide by constriction, invagination of the inner membrane or arrangement of vesicles in the division plane.

Influence of kinetin on storage protein mobilization and ultrastructure of plastids in excised lupine cotyledons grown in darkness

Storage protein disappeared first from the peripheral and later from central parts of the lupine cotyledon. Kinetin (500 μM) stimulated this process; its effect was most prominent after longer times of incubation. In plastids large, crystalline prolamellar bodies were observed. They some-times split into smaller parts during the course of the experiment, especially in the kinetin-treated material. Kinetin in darkness did not stimulate formation of thylakoid membranes (neither grana nor primary lamellae).

Stereometrical analysis of number and size of prolamellar bodies during pea chloroplast development

The plastid prolamelar bodies in dark-grown pea seedlings undergo gradual transformation and decay after illumination with low intensity light. Random micrographs do not give direct information concerning the sizes and average numbers of prolamellar bodies in a plastid. These values were obtained after evaluation by a stereometrical method from the ratio of polamellar bodies sizes to the plastid size and from the frequency of prolamellar body sections of a given diameter. Plastids of dark-grown seedlings contained on the average at least one prolamellar body. After illumination the size of the bodies decreased rapidly owing to dispersion into primary thylakoids and split into much smaller numerous prolamellar bodies.

The effect of kinetin on cytochemical localization of Mg++ dependent ATP-ase in isolated lupine cotyledons

ATP-ase activity stimulated with Mg⁺⁺ ions was localized cytochermically in lupine cotyledons. Studies were also made of the effect of kinetin on this activity. Activity of Mg⁺⁺ dependent ATP-ase was observed in plasmalemma, nucleus, nucleolus, endoplasmic reticulum, thylakoid membranes, prolamellar bodies, cell wall, and irilter-cellular spaces. Kinetin (6-furfurylaminpurine) used in the experiment, stimulated ATP-ase activity, but dad not affect its localization.