Original scientific paper

Study of Nucleoids in Bean Chloroplasts by Fluorescent and Electron Microscopy

Zora Modrušan ; Hrvatska
Nikola Ljubešić ; Hrvatska
Mercedes Wrischer ; Hrvatska

Abstract

The DNA containing areas of chloroplasts, so-called nucleoids, were studied within bean chloroplasts by fluorescent and electron microscopy. The use of the DNA specific fluorochrome DAPI (4’6-diamidino-2-phenylindole) makes it possible to examine, in situ with fluorescent microscope, some characteristics of organization of nucleoids in chloroplasts. Fully developed bean chloroplasts contain a moderate number (approximately 25—40) of small (dimeter 0.2—0.4 pm), spherical nucleoids randomly distributed throughout the chloroplast. According to these characteristics the bean belongs to the SN (scattered nucleoids) group. Chloroplast nucleoids were also observed by electron microscopy with the use of specific preparative technique for better visualization of nucleoids. These investigations partly confirm the results about the organization of nucleoids obtained by fluorescent microscopy. The nucleoids in dividing bean chloroplasts are organized in the same way as in non- dividing chloroplasts. A similar quantitative portion of nucleoids was determined in dividing (17.4%>) and in non-dividing (16.9%) bean chloroplasts by morphometric measurements. It has been established that parallelly with the enlargement of chloroplast size before its division their nucleoids increase as well. They are evenly distributed within each half of chloroplast before the end of chloroplastokinesis. Complete division of chloroplast restores the initial number and distribution of nucleoids in two daughter chloroplasts

Keywords

Hrčak ID:

159503

URI

https://hrcak.srce.hr/159503

Publication date:

31.12.1989.

Article data in other languages: croatian

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