Oil bodies are important intracellular organelles found in liverworts. Oil bodies can be used for taxonomy and also for understanding the great variation within the bryophytes.
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.
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.
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.
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.
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.