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Oil bodies and their relative importance in the systematics of bryophytes
- 1. Oil Bodies and Their Relative Importance in the Systematics of Bryophytes By- Meenakshi Das Assam University, Silchar
- 2. • Bryophytes are small, non-vascular plants, such as mosses, liverworts and hornworts. • There are around 24,000 species of Bryophytes. • Liverworts include approximately 8000 species. • The are found on all continents, occupying arid to aquatic niches. • One of the putative evolutionary innovations of liverworts is the presence of OIL BODIES. • Oil Bodies are present in both gametophytes and sporophytes. Marchantia polymorpha Introduction
- 3. Oil Bodies- Unique & Important Organelles In Bryophytes Marchantia polymorpha Illustration of oil bodies in Marchantia polymorpha, (a.) oil bodies, (b.) chloroplasts (by Mirbel 1835) Photograph Source- Wikipedia
- 4. Oil Bodies • Intracellular organelles • Bounded by single unit membrane • Contains lipophilic globules suspended in a proteinaceous matrix • Prominent and highly distinctive organelle uniquely found in liverworts • Widely used in Taxonomy and Chemosystematics
- 5. Oil Bodies Of Liverworts Nardia scalaris Photograph of Oil Bodies of Nardia scalaris Source- Wikipedia
- 6. Variation of Oil Bodies • Oil bodies show a wide range of variation in- SIZE NUMBER (PER CELL) CONFIGURATION • The characters variation takes place among liverworts as a whole but are rather invariable within a species. • The characters of oil bodies are not affected by environmental condition.
- 7. • More than 90% of Liverwort species contain Oil Bodies in their cells. • The phylogenetic studies have shown that oil bodies in some groups have been lost independently at different times during the course of evolution. • Some species also have oil bodies that are difficult to distinguish from cytoplasmic lipid droplets under a light microscope because of their small size and so the unit membrane cannot be seen. Examples are genera Drucella, Kurzia, and Metzgeria.
- 8. Source- Wikipedia Ptilidium ciliare Photograph of Oil Bodies of Ptilidium ciliare Leafy Liverwort with Oil Bodies
- 9. Source- Wikipedia Cephalozia connivens Leafy Liverwort Lacking OIL BODIES!!!!! Photograph of cells of Cephalozia connivens
- 10. Functions of Oil Bodies • PROTECTION against Herbivores Pathogens Cold temperatures UV radiation Dessication • Biochemical studies have also shown that isoprenoid biosynthetic pathway taking place in the liverworts are similar to those of seed plants.
- 11. Discovery of Oil Bodies in Liverworts • The oil bodies of liverworts were first described by Hübener (1834) from leafy liverwort Jungermannia taylorii (Mylia taylorii). • He described oil bodies as transparent drops, with shining, membranous texture. • Pfeffer (1857) designated them as Ölköper (Oil Bodies) because of their fatty nature. • Pihakashi (1972) confirmed with light and electron microscope studies that oil bodies are the main sites of lipids in the cells of Liverworts. Transmission electron micrograph of mature oil bodies of Lophozia ventricosa. At 11,000 x (by Pihakaski ,1966)
- 12. Origin of Oil Bodies • There are different opinions for the origin of oil bodies in liverworts • Pihakashi (1968) suggested that oil bodies in Bazzania trilobata are formed from vacuole-like structures into which ER or Golgi apparatus secretes substances as small droplets whereas in Lophozia ventricosa developed from fusion of cytoplasmic lipid droplets and the cytoplasm around it forms a limiting membrane. • Suire (1970) who was working on Radula complanata concluded that the oil bodies originate from dilated ER cisternae. • Ultrastructural evidence supports the hypothesis that oil bodies originate from the dilation of endoplasmic reticulum cisternae.
- 13. Origin of Oil Bodies • In complex thalloid Liverworts, the origins of the oil bodies are quite different. • In Marchantia paleacea the oil bodies originate from fusion of Golgi-derived vesicles and dilation of the ER membrane (Galatis and Apostolakos 1976; Galatis et al. 1978). • Suire (2000) finally reports that “oil bodies originate from the same cell membrane system and basically develop in the same way in all the Hepaticae,” and considers that M. paleacea presents a unique variation in the ontogenic process of the oil bodies.
- 14. Taxonomy & Phylogeny • The oil bodies of liverworts occur not only in the gametophytes but also in the sporophytes including seta and spores (Müller, 1939; Suire, 1966, 1970; Pihakaski, 1972). • Their size ranges from less than 1 μm to nearly 30 μm in diameter. • They are often most visible organelle of the cell. • The oil bodies are best observed from living material. • Under light microscope, oil bodies are usually recognizable by their high refractive index. • They appear to be colorless, or various densities and tints of brown (Calypogeia and most Acrobolbaceae). • Oil bodies may be homogenous or segmented.
- 15. Calypogeia muelleriana Photograph of Oil Bodies of Calypogeia muelleriana Photograph Source- Wikipedia
- 16. • Oil bodies occur in all the mature cells of the gametophyte and sporophyte in the Jungermanniopsida and Haplomitriales. • They are usually restricted to specialized idioblasts in Marchantiopsida and Treubiales.
- 17. Frullania pycnantha © Matt von Konrat, 2004 · 9 Photograph of Oil Bodies in the sporophyte of Frullania pycnantha Photograph Source- Wikipedia
- 18. Types of Oil Bodies • Müller (1939) was the first to suggest a system of classifying the oil bodies into different groups. • He recognized nine types of oil bodies. • He did the classification on the basis of their appearance, size and form. • Gradstein et al. (1977) proposed four types of oil bodies and divided them into homogeneous and segmented types. • The homogeneous ones were divided into Massula-type and Bazzania-type, and segmented ones into Jungermannia-type and Calypogeia-type. • Therefore, the shape, number, size, colour and distribution of oil bodies vary considerably and they have been recognized as taxonomically important.
- 19. • The oil body types were used as a primary criterion to separate genera of Ptychanthoideae of the family Lejeuneaceae (Schuster and Hattori, 1954). • Distinguishing taxa at species and genus levels using oil body characters have also been widely used for leafy and simple thalloid liverworts, especially in families Lejeuneaceae, Frullaniaceae and Radulaceae. Some oil body chemical evidences are also considered.
- 20. Different types of oil bodies in the cells of liverworts: (a–b) Calypogeia- Type (c–d) Jungermannia- type; (e) Bazzania-type (f) Massula-type a. Calypogeia azurea b. Cheilolejeunea anthocarpa c. Radula constricta d. Solenostoma truncatum e. Bazzania tridens f. Trocholejeunea sandvicensis
- 21. Oil Bodies and their chemical constituents • Oil bodies contain secondary metabolites such as terpenoids and aromatic compounds. • Many of these are BIOACTIVE. • These bioactive compounds are considered as potential sources of Medicines.
- 22. Chemosystematics and Pharmaceutical Applications • Most of the compounds found in liverworts are composed of terpenoids and aromatic compounds. • Among terpenoids are the mono-, sesqui- and diterpenoids. • Among aromatic compounds are the bibenzyls and bisbibenzyls. • Terpenoids represent the oldest group of small molecular products synthesised by plants. • Pinguisane-type sesquiterpenes and sacculatane- type diterpenoids are only found in liverworts.
- 23. Pinguisane-type sesquiterpenes are significant chemical constituents of Porella species (Asakawa et al., 1981a, b; Asakawa, 1982, 1995, 2001; Hashimoto et al., 2000). Unique chemical compounds of Pinguisane-type sesquiterpenes a. Porella platyphylla, b–c. Porella acutifolia subsp. tosana
- 24. Sacculatane diterpenoids are found in Pellia, Pallavicinia, Fossombronia, Trichocoleopsis, and Porella (Asakawa, 2004). Unique chemical compounds of Sacculatane diterpenoids d–e. Pellia endiviifolia f. Trichocoleopsis sacculata.
- 25. • Liverworts have more sesqui- and diterpenoids than monoterpenoids. • According to Asakawa (1995), they are mainly responsible for the characteristic odour of liverworts. • Terpenoids and lipophilic aromatic compounds have been used extensively as chemosystematic indicators (Asakawa, 2004). • The importance of chemosystematics of liverworts in 36 families at different taxonomic levels was also discussed by Asakawa.
- 26. • For EXAMPLE- The specific terpenoids and bis-bibenzyls, such as pinguisane sesquiterpenoids, which are the characteristic markers of the leafy liverworts, are also found in simple thalloid Aneura species (Asakawa, 1995). This was considered as a close relationship between the two groups. • The molecular systematic studies have also shown that there is a close relationship between leafy liverworts and the group consisting of Aneuraceae and Metzgeriaceae (He-Nygr´en et al., 2006). • Chemisystematics have also been used to distinguish family Frullaniaceae from Jubulaceae, and Lepidolaenaceae from Trichocoleaceae (Asakawa, 2004).
- 27. Oil bodies & Evolution of Land plants • Much of the tissue of liverworts is only one cell thick, grows closely to the substrate and has no mechanical protection such as bark or cuticle. • The ability of liverwort oil bodies to undergo dynamic metabolic fluxes of their matrix constituents may have provided a competitive evolutionary advantage. • This ability may have been a very early prerequisite for survival on land of the earliest land plants
- 28. Conclusion & Future Directions • Oil bodies are the most important organelles in liverworts but our understanding of the evolution and function of oil bodies is quite less. • Novel tools are required for visualization and exploration of oil body origin, development and dynamics, and enhancements of imaging techniques such as high resolution electron microscopy is also required. • This would ultimately help in decoding the biology and evolution of the oil bodies of the liverworts. • Better understanding of liverwort oil body metabolism will also provide knowledge for their potential pharmaceuticals applications.
Editor's Notes
- metabolic flux is the rate of turnover of molecules through a metabolic pathway. Flux is regulated by the enzymes involved in a pathway. Within cells, regulation of flux is vital for all metabolic pathways to regulate the pathway's activity under different conditions.