Abstract
The fine structure of leucoplasts in root tip cells of Phaseolus vulgaris L. has been studied in material fixed in glutaraldehyde followed by osmium tetroxide and poststained in uranyl acetate and lead citrate. Plastid development has been followed from the young stages in and near the meristematic region, through an ameboid stage, to the larger forms with more abundant storage products in the outermost cells. The plastids contain a dense stroma penetrated by tubules and cisternae arising from the inner membrane of the plastid envelope. Also located in the stroma are lamellae, ribosome-like particles, phytoferritin granules, and fine fibrils in less dense regions. In some elongate plastids microfilaments run lengthwise in the stroma near the surface. The same plastids store both starch and protein, but in a strikingly different manner. The starch is deposited in the stroma, while the protein always is accumulated within membrane-bounded sacs. These sacs arise as outgrowths from a complex of interconnected tubules which in turn appears to originate by coalescence and proliferation of tubules and cisternae arising from the inner plastid membrane. This "tubular complex" bears a strong resemblance to the prolamellar body of etiolated chloroplasts, but is smaller and ordinarily less regularly organized, and is apparently light-insensitive. Crystallization of the protein commonly occurs in the sacs and occasionally takes place within the tubules of the complex as well. The fine structure of the leucoplasts is discussed in relation to that of etiolated chloroplasts. Suggestions are made concerning the function of the tubular complex, role of the ameboid plastid forms, and manner of accumulation of the storage protein in the plastids.
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Selected References
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- Bonnett H. T., Jr, Newcomb E. H. Polyribosomes and cisternal accumulations in root cells of radish. J Cell Biol. 1965 Nov;27(2):423–432. doi: 10.1083/jcb.27.2.423. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Esau K. FIXATION IMAGES OF SIEVE ELEMENT PLASTIDS IN BETA. Proc Natl Acad Sci U S A. 1965 Aug;54(2):429–437. doi: 10.1073/pnas.54.2.429. [DOI] [PMC free article] [PubMed] [Google Scholar]
- GIBOR A., GRANICK S. PLASTIDS AND MITOCHONDRIA: INHERITABLE SYSTEMS. Science. 1964 Aug 14;145(3633):890–897. doi: 10.1126/science.145.3635.890. [DOI] [PubMed] [Google Scholar]
- GUNNING B. E. THE FINE STRUCTURE OF CHLOROPLAST STROMA FOLLOWING ALDEHYDE OSMIUM-TETROXIDE FIXATION. J Cell Biol. 1965 Jan;24:79–93. doi: 10.1083/jcb.24.1.79. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HUXLEY H. E., ZUBAY G. Preferential staining of nucleic acid-containing structures for electron microscopy. J Biophys Biochem Cytol. 1961 Nov;11:273–296. doi: 10.1083/jcb.11.2.273. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HYDE B. B., HODGE A. J., KAHN A., BIRNSTIEL M. L. STUDIES ON PHYTOFERRITIN. I. IDENTIFICATION AND LOCALIZATION. J Ultrastruct Res. 1963 Oct;59:248–258. doi: 10.1016/s0022-5320(63)80005-2. [DOI] [PubMed] [Google Scholar]
- Heslop-Harrison J. Ultrastructural aspects of differentiation in sporogenous tissue. Symp Soc Exp Biol. 1963;17:315–340. [PubMed] [Google Scholar]
- Jacobson A. B., Swift H., Bogorad L. Cytochemical studies concerning the occurrence and distribution of RNA in plastids of Zea mays. J Cell Biol. 1963 Jun;17:557–570. doi: 10.1083/jcb.17.3.557. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MOLLENHAUER H. H. PLASTIC EMBEDDING MIXTURES FOR USE IN ELECTRON MICROSCOPY. Stain Technol. 1964 Mar;39:111–114. [PubMed] [Google Scholar]
- MUEHLETHALER K., FREY-WYSSLING A. [Development and structure of proplastids]. J Biophys Biochem Cytol. 1959 Dec;6:507–512. [PMC free article] [PubMed] [Google Scholar]
- Northcote D. H., Pickett-Heaps J. D. A function of the Golgi apparatus in polysaccharide synthesis and transport in the root-cap cells of wheat. Biochem J. 1966 Jan;98(1):159–167. doi: 10.1042/bj0980159. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Price W. C., Martinez A. P., Warmke H. E. Crystalline inclusions in chloroplasts of the coconut palm. J Ultrastruct Res. 1966 Mar;14(5):618–621. doi: 10.1016/s0022-5320(66)80086-2. [DOI] [PubMed] [Google Scholar]
- REYNOLDS E. S. The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J Cell Biol. 1963 Apr;17:208–212. doi: 10.1083/jcb.17.1.208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wohlfarth-Bottermann K. E. Cell structures and their significance for ameboid movement. Int Rev Cytol. 1964;16:61–131. doi: 10.1016/s0074-7696(08)60294-6. [DOI] [PubMed] [Google Scholar]