review of literature - information and library...
TRANSCRIPT
Page | 13
CHAPTER 2
REVIEW OF LITERATURE
2.1 Floristic account of lichens
International scenario
The foremost taxonomic account of lichens comprising 80 species was published
under the 24th
class of cryptogamic algae in species planetarium (Linnaeus, 1753).
Extensive exploration, collection and curation of lichens from different parts of the
world, particularly from tropical and subtropical regions of Asia, Africa and America
were taken up in 19th
and 20th
centuries. Several publications dealing with the lichens of
Arctic (Thomson, 1972), North America (Le blanc, 1963), the Alps (Kalb, 1970),
Antartica (Øvstedal and Smith, 2001), Gambia (Aptroot, 2001), Korea (Hur et al., 2005),
Page | 14
Australia (Sparrius et al., 2010), Belgium, Luxembourg and northern France (Diederich
et al., 2012) and Leningrad, Russia (Himelbrant et al., 2014) were also made.
Most recently, epiphytic lichens in south-west Mediterranean Europe along an aridity
gradient within the semi-arid and on the border of its transition to the dry-sub humid were
sampled as well as the lichens key functional traits and functional group that responds to
aridity in dryland ecosystems were identified (Matos et al., 2015).
A range of about 13500 to 20000 species belonging to 650 genera of lichens from all over
the world documented (Hawksworth and Hill, 1984). The figure range of lichen species
could be further increased with the discovery and development of cryptic species (Grube
and Kroken, 2000). Sipman and Aptroot (2001) also claimed that the lichens known from
all over the world included „orphaned‟ species, the species which had not or rarely been
recorded after their initial description and were not covered in present day revisionary
studies. A database containing 18882 species including about 1560 lichenicolous fungi
was also published (Lawrey and Diederich, 2003). Later, a first draft of a global checklist
of lichens and allied fungi was listed based on the checklist of 132 geographical units
(Feuerer and Hawksworth, 2006) by calculating the similarities of lichenized fungal
species composition among the 35 floristic regions which was recognized by Takhtajan
(1986).
Lichens are usually a copious component of most phanerogamic vegetation and are
dominant in both the Arctic and the Antarctic communities. A total of about 2000 lichen
species were recorded from Arctic Alaska, most of which were of pre-Pleistocene origin
alone, indicating remarkable diversity even after reduction of various species to
synonym (Thomson, 1972). A total of 484 lichenized fungi taxa from Antarctica and
South Gorgia including four additional lichen species and a new species of Leciophysma
sp were reported by Øvstedal and Lewis (2011).
Different facets on lichens from various regions were also well studied in different
countries, giving special importance on the floristic account. The abundance and
distribution of lichens in Irish woodlands had been studied extensively (Fox et al., 2001;
Coppins and Coppins, 2002). Twenty five lichen species along with Caloplaca
Page | 15
gambiensis had been reported as new to science from Gambia (Aptroot, 2001). An
enumeration of 114 species of epigeic bryophytes and lichens along with a total of 297
vascular plants was registered while surveying ground floor vegetation of the forest
ecosystem in Germany (Seidling, 2005). Feuerer and Hawksworth (2006) reported that
probably more than 95 percent of the existing species were known from Austria
(Hafellner and Tück, 2001), Great Britain and Ireland (Coppins, 2002) and Fennoscandia
(Santesson et al., 2004). Galloway (2007) reported that 23% of the lichen biota was
endemic in New Zealand.
Studies had shown that the species diversity of macrolichens in subtropical areas was
distinctly higher in secondary forests due to a constant input of propagules from nearby
primary forests, high landscape connectivity, high host species diversity and moderately
open canopies (Li et al., 2007, 2011).
61 species of lichens had been recorded in the Ailao Mountians (Li et al., 2007). The
lichen flora of Rwanda, east-central Africa consisting of a total of 178 lichenized fungi
and four lichenicolous fungi was provided by Bock et al., (2007).
Though lichens are ubiquitious and form a key component of epiphytes in subtropical
forests, they are poorly understood. Primary or old-growth forests usually act as refuges
for epiphytic lichens (Nascimbene et al., 2010; Ellis, 2012). A comparative study on the
lichen species richness and species composition between Estonian and Fennoscandian old
coniferous forests were documented, giving special emphasis on woodland key habitat
indicator species. The study also reported a total of 151 lichen species in the aerea
(Marmor et al., 2011). An extensive review on the lichenological history of Saint Lucia
and reported 238 lichens and 2 lichenicolous fungi from published literature and
catalogues of herbarium specimens was presented recently (Fox and Cullen, 2014).
Li et al., (2013) assessed the potential of anthropogenic secondary forests as conservation
sites for epiphytic lichens by investigating epiphytic lichens in 120 plots of eight
representative forest types of the subtropical Ailao Mountians, southwest china and
recorded a total of 217 epiphytic lichen species with 83% occurring in primary forests
and 97% in secondary forests. Matos et al., (2015) also identified and classified a total of
Page | 16
161 species of epiphytic lichens in south-west Mediterranean Europe according to three
traits viz. types of primary photobiont, growth form and types of reproduction.
The floristic accounts of a special group of lichens known as foliicolous lichens that
usually colonized on live leaves was published for the first time by Allan (1928).
Numerous sporadic publications on foliicolous lichens were also made by Santesson
(1952); Benzing (1986); Seaward (1988); Sérusiaux (1989, 1997); Barillas et al.
(1993); Sipman (1997); Lücking (1995, 1997, 1998, 2000, 2008), Lücking et al. (2000);
Cáceres et al. (2000); Sanders (2001); Anthony et al. (2002); Kirk et al., (2008).
Lücking (2003) also examined the diversity and species composition of foliicolous
lichens based on the Takhtajan‟s floristic regions. An inventory of foliicolous lichens in
Mexican lowland and montane rainforest revealed the presence of 288 species of which
238 were new reports for the country (Herrera-Campos et al., 2004). Aptroot and
Sparrius (2006) reported substantial numbers of foliicolous lichen taxa from pantropical
genera.
The phytosociological approach for analyzing plant communities had been effectively
employed to demonstrate the wide variety and complexity of lichen communities (James
et al., 1977; Roux, 1981). Wirth (1983) studied the phytosociology, ecology and
taxonomy of lichen and documented that ecological similarities of lichen taxa can also be
proved by phytosociological methods, but the study was hindered due to the difficulties
in taxonomic grouping of crustose lichens, which account for most of the diversity in the
lowland forest (Sipman and Harris, 1989) and are mostly under collected.
The development of particular assemblages of lichens is determined by large number of
ecological factors such as climate, topography and geology as well as the prevailing land
use (roads or farm), habital fragmentation and the extent of pollution (Orange, 1994;
Moen and Jonsson, 2003). The distribution and composition of epiphytic lichens was also
found to be quite dependent on altitude of the region. Studies of altitudinal effects on
lichen diversity indicated that species diversity tends to decrease with increasing
elevation, however, at some intermediate level of elevation, it peaked giving rise to a
humped-shaped relationship (Bruun et al., 2006).
Page | 17
Substratum qualities such as age of the part of tree where the lichen is growing, bark
texture, bark chemistry, forest productivity and aspect are also factors that determined the
floristic composition of epiphytic lichen communities (Gustafsson et al., 1992; Selva,
1994; Jüriado, et al., 2003). The pH of the bark is another significant parameter that has
been studied intensively by various workers (van Herk, 2001; Kricke, 2002). Will-Wolf
et al., (2002) suggested that forest age and the continuity of forest canopy are also one of
the most vital factors that can hinder the development of epiphytic lichen communities.
The presence of other epiphytes, nutrient status, water holding capacity and buffer
capacity are the range of bark related parameters which determined the lichen
development (Larsen et al., 2007).
Bricaud (2008) mentioned that species which retain leaves for many years have the
potential to be habitats for a rich and interesting flora of foliicolous lichen. The ecology
of tropical lichens, in general, can be better understood for foliicolous habitats than for
corticolous habitats (Lücking, 2008).
A survey was conducted in the Swiss Central Plateau and the Pre-Alps for identifying
representative and quantitative criteria for the creation of Red List of epiphytic lichens
by describing the frequency data of the lichen taxa observed, based on the trees and
also by calculating the á-diversity (species richness, species density) and á-diversity
(dissimilarity) in terms of region, vegetation Formation, vegetation belt and for their
combinations (Dietrich and Scheidegger, 1997).
A quantitative method for describing lichen vegetation based on screening grid across the
truck of tree between 0.3 and 1.3 m above the ground also known as the “Flechtenleiter”
was introduced by Kricke and Loppi (2002). Li Su et al., (2007) carried out their
studies on species diversity and distribution of epiphytic lichen in the primary and
secondary forest of Ailao Mountains, Yunnan and studied the species composition
and distribution of epiphytic lichen of tree trunks at 0–2.0 m height and reported
significant differences in composition and diversity of epiphytic lichen on trunks
between the primary and secondary forests. A comparison of epiphytic lichens
composition for three types of woodland in Knocksink Wood was conducted using
Page | 18
multivariate analysis and Sørensen coefficient and the study indicated that there were
floristic differences between the woodland types and a strong similarities in lichen
species composition (Mulligan, 2009). Hauck (2013) studied the edge effects on
epiphytic lichen diversity in the forest-steppe of the Kazakh Altai and found out that
the epiphytic diversity in the forest interior was similar in the Kazarkkh and
Mongolian Altai, whereas the diversity at forest edge was lower in Mongolian Altai.
Hauch et al., (2013) mentioned that the diversity and ecology of epiphytic lichens in the
Eurasian Forest-Steppes were under-studied though the vegetation type stretches almost
9000 km across the continents along the border of the forest and the steppe zones.
Armstrong (2015) reported that effects of environmental factors on growth can act
directly to restrict species distribution or indirectly by altering the competitive balance
among different species in a community.
National scenario
Information about lichens of the Indian subcontinent was brought together right from the
time of Linnaeus who reported the occurrence of two taxa, Lichen fuciformis (L.) D.C.
and Rocella montagnei Bél. in his magnum opus „Species Plantarum‟ (Linnaeus, 1753).
Gradually, several taxa were added on the accounts of Indian subcontinent by various
European lichenologists such as Belanger (1838); Montagne (1842); Nylander (1860,
1867, 1869, 1873); Műll Arg. (1892); Jatta (1902, 1905, 1911); Smith (1931).
Awasthi (1965) later conducted a detailed floristic study on the Indian lichens in a
systematic way and reported the occurrence of about 1310 species from the Indian sub-
continent including Ceylon, Nepal, Pakistan, and Sri Lanka. Later, a total of 685 species
of lichens were added to this study (Singh, A., 1980). Keys of 1850 species of lichens
including 700 of foliose to fruticose macrolichens were prepared by Awasthi (1988) and
again another 1150 of crustose to squamallose microlichens (Awasthi, 1991), adding
about 500 lichen taxa to the already known lichen flora of the Indian sub-continent.
Study on the floral diversity and distribution of lichens in India flourished extensively
since the last three decades. An rather extensive account on the lichens of Himalayas as
well as those of tropical, temperate and alpine regions of India were documented
Page | 19
(Upreti, 1997, 1998). Lichens of the genera Baeomyces, Cladonia and Pyrenula were
studied in detailed (Upreti, 1995, 1987, 1990, 1991a, 1991b, 1993). A total of 85
macrolichens were recorded from Baniyakund-Chopta of Garhwal (Negi, 2000).
Parmelioid lichens of India were described by Divakar and Upreti (2002, 2003, 2005,
2006). Upreti et al. (2004) studied the lichen flora of Gangotri and Gomukh areas of
Uttarakhand and reported 149 lichens species belonging to 50 genera and 21 families. An
enumeration of 106 lichen species belonging to 47 genera and 28 families from
Baniyakund-Chopta of Garhwal was provided by Kumar (2009) and documented that the
lichen diversity of the area when compared with other regions was about 30% of the
Garhwal Himalayas, 20% of Uttarakhand and 10% of the Himalayas and less than 0.55 of
the Indian lichen diversity.
An annotated checklist of taxa of Indian lichens comprising about 2326 species belonging
to 305 genera and 74 families was documented by Singh and Sinha (2010) based on the
consolidated data on Indian lichens by various national and international lichenologists
and further reported that the estimated number of Indian lichens were lower as many
areas especially mountains and the forest canopies are yet to be explored.
Shyam et al., (2011) enumerated 48 species belonging to 23 genera and 12 families of
lichens from Kollihills of Namakkal district, Tamil Nadu and expressed that the lichen
flora of the area exhibited similarity with that of Megamali Wild life Sanctuary of
Kambam district (Nayaka et al., 2001) and Shervaroy hills, Tamil Nadu (Hariharan et al.,
2003). Logesh et al., (2012) again reported 21 species belonging to 14 genera and 10
families of lichen from Pichavaram and Muthupet mangroves of Tamil Nadu.
Upreti et al., (2010) for the first time reported the genera Miriquidica and Lecidoma, a
squamulous lichens from temperate to alpine regions of western Himalaya, India along
with three other new records of species of the genera Toninia.
Numerous publications on foliicolous lichens were also made by various lichenologist
like Awasthi and Singh (1972a, 1972b, 1973); Pinokiyo and Singh (2004); Ramamoorthy
et al., (1993); Sethy and patwardhan (1987); Singh J.S. (2002); Singh (1979); Singh and
Pinokiyo (2003, 2004).
Page | 20
As many as 48 species of foliicolous lichens were reported from Andanam and Nicobar
Islands by Singh, A. (1969, 1970, 1971, 1973, 1979). Sethy and Patwardhan (1987)
added another 20 species of foliicolous lichens to the lichen flora of Andnam and Nicobar
Islands. Awasthi (1991) recorded ca 100 species of foliicolous lichens from Indian
subcontinents while preparing keys to the microlichens of India, Nepal and Sri Lanka.
Makhija et al., (1994) reported 32 species of foliicolous lichens of the Porina from India.
A single species of foliicolous lichen was also recorded from Baniyakund-Chopta of
Garhwal while conducting an assessment of lichen species in a temperate region of
Garhwal Himalaya (Kumar, 2009).
Negi and Gadgil (1996) analyzed data in order to document the relative number of lichen
genera and their distribution, alpha and beta diversity, niche-width and niche overlap
along the wide range of habitat types in the specified altitudinal range of Nanda Devi
Biosphere Reserve. Species richness, density and population structure of all lichen
species were investigated in human modified tropical dry evergreen forest of Indian
Institute of Technology, Chennai (Balaji and Hariharan, 2013).
Regional (North East India) scenario
The earliest publication on lichens of the Eastern Himalayas, including the north eastern
states consisted of 80 species (Nylander, 1860, 1863). Various new taxa of lichens were
also reported from the collection of G. Watt and A .Watt from Assam and Darjeeling
(Stirton, 1879, 1881). Later after a long gap of almost a century, Chopra (1934) revived
the work on lichens of India and published a comprehensive account of lichens of Eastern
Himalayas. The study on lichens of the region was further improved by Asahina (1966);
Awasthi (1965, 1988, 1991, 2007); Patwardhan and Nagarkar (1979, 1980, 1982; Singh
(1981a, 1981b); Sinha and Singh (1986, 1991); Singh and Sinha (1994, 1997, 2010);
Rout (2010a, 2012, 2013). Altogether, a total of 1162 species of lichens have been
reported from the Eastern Himalayan region (Sinha and Jagadeesh, 2011).
Awasthi (1961) reported some foliose and fruticose lichens collection from Assam and
Arunachal Pradesh ( then known as North-East frontier Agency, NEFA). Singh and Sinha
(1994) reported 331 species of lichens from Nagaland with 136 species being new
Page | 21
addition to the lichen flora of North-East India. Ahti et al., (2002) described Cladonia
singhii as new report from eastern Himalayas. Upreti et al., (2004) studied the lichen
flora of Sikkim and resulted in addition of as many as 181 species representing 56 genera
and 33 families as new records for the state. Later, a list of 505 lichen species was
reported from Sikkim (Sinha and Jagadeesh, 2011).
An enumeration of 73 species of lichens from Namdapha National park, Arunachal
Pradesh was reported (Singh, 1996). Singh and Bujarbarua (2001) prepared a preliminary
account on the status of lichen diversity of Arunachal Pradesh. Rout et al. (2004) reported
that out of the 843 species known from Northeast India, Arunachal Pardesh is represented
by 112 species. Dubey et al. (2007) enumerated 94 species of lichens belonging to 20
families and 40 genera from Along town, West Siang district, Arunachal Pradesh and
also reported that the areas with more human intervention exhibited less lichen diversity
(only 36 species) while areas with lesser anthropogenic activities had more diverse lichen
flora (71 species). A study of the diversity and distribution of lichens within the Mehao
Wildlife Sanctuary in Arunachal Pradesh, India was also conducted by Pinokiyo et al.
(2008) and the study revealed the presence of 177 species of lichens belonging to 71
genera and 35 families. Other workers who made important contributions to the lichen
flora of Arunachal Pradesh were Singh (1999); Singh and Pinokiyo (2004); Singh et al.,
(2004, 2005). Singh and Pinokiyo (2003) reported 76 species from North-East India with
3 new records of foliicolous lichen. Singh et al., (2004) also published 18 species of
foliicolous lichens from Mehao Wildlife Sanctuary, Arunachal Pradesh. Pinokiyo et al.
(2004) reported 21 foliicolous species of the genus Porina from Arunachal Pradesh with
3 were new records for India. Further studies on collection have shown that a total of 76
species are distributed in Meghalaya, Mizoram, Manipur, Nagaland, Sikkim and West
Bengal. Rout et al., (2005b, 2010b) documented the epiphytic lichen diversity in NIT
campus and a Reserve forest of the Barak Valley of Assam. From southern part of
Assam, another 37 epiphytic lichen species were enumerated belonging to 16 genera and
10 families from betel nut palm (Areca catechu) as host tree from an abandoned tea-
garden area with sporadic human habitation (Rout et al., 2012). Daimari, et al., (2014) for
the first time enumerated lichens of Baksa, Kamrup and Sonitpur district of Assam and
Page | 22
recorded 67 species of lichens belonging to 12 families and 24 genera with 41 new
records of Assam.
A comparative data on the lichens of North-Eastern states was given by Sinha and
Jagadeesh (2011) and accordingly the highest numbers of species recorded to that date
was Sikkim (506) followed by Arunachal Pradesh (477), Nagaland (306), Manipur (291),
Meghalaya (179), Assam (141) and Mizoram (02) while no reports have been made from
Tripura at the time of his study. Recently Upreti et al., (2014) for the first time reported a
total of 30 species of lichens belonging to 17 genera and 11 families from north and
western districts of Tripura. An enumeration of 159 species of lichens from Mizoram
with 14 new records for India has been furnished very recently (Logesh et al., 2015).
For the state of Manipur, the foremost publication on taxonomic account of lichens was
contributed by Müll. Arg. (1892, 1895) from the collection made by G. Watt. The most
important contribution in the history of lichens of Manipur was the description of an
entirely new lichen genus Awasthiella of the genus Verrucariaceae on the basis of
material collected from Manipur (Singh, 1980). Singh (1981a, 1981b) worked on the
microlichens and macrolichens of Manipur and published various new taxa and new
records. Singh and Singh (1982), during the course of studies on lichens of Manipur,
found two new species, Buellia manipurensis and Buellia morehensis. A new species of
lichens Catillaria manipurensis was reported by Singh (1983). Singh and Singh (1984)
again conducted a detail study on the species of Buellia and Diplotomma from Manipur
and reported few new records of India. Singh and Upreti (1986) dealt with 21 taxa of the
lichen genus Cladonia from Arunachal Pradesh and Manipur and reported that Cladonia
calycantha, C. farinacea, C. gymnopoda and C. parasitica were new reports of the Indian
lichen flora. Singh (1977, 1978, 1979) while working on the Lichens of Manipur reported
7 new records of foliicolous lichens flora of India. After a long gap of almost a decade,
Rout et al. (2013) conducted a preliminary study on the lichens of Keirao Wangkhem of
Manipur and revealed the presence of 19 species, belonging to 13 genus and 9 families.A
series of publications on floristic diversity of lichens of Manipur and on various new taxa
and many new records had been made (Awasthi 1960a, 1960b, 1980, 1987, 1991; Singh
1977, 1978, 1979, 1980, 1981a, 1981b, 1983, 1999; Patwardhan.and Nagarkar 1982;
Page | 23
Singh, A. 1984; Singh and Singh, 1984; Singh and Upreti, 1986); Upreti, 1990, 1993;
Singh and Sinha, 1994). However, the report on floristic account of lichens of Manipur is
not yet complete.
2.2 Lichens as biomonitor
International scenario
Lichens are one of the most sensitive and effective biomonitors for mapping spatial and
temporal changes of atmospheric contamination (Nimis et al., 2002). Kricke and Loppi
(2002) reported that epiphytic lichen vegetations have a long history of being used as
biological indicators of ambient air quality as they are the first to be affected by
environmental contamination. Lichens comprise a unique group which are among the
most significant indicators of environment and also are sensitive towards habitat variation
(Rai et al., 2011).
The used of lichens as bioindicators have been studied in different parts of the world for
the detection of different pollutants such as the impact of urban pollution (Gombert et al.,
2004), refuse incineration (Gombert and Asta, 1997); ammonia from intensive farming
(Van Herk, 2002); nitrogen deposition (Gombert et al., 2003) and also for studying the
changes associated with short or long range deposition of atmospheric pollutants from
industry and fossil fuel burning; as indicators for human health (Cislaghi and
Nimis,1997) and also for demonstrating the respond to global warming (Van Herk et al.,
2002).
The use of lichens as one of the most significant atmospheric monitors for spatial and
temporal deposition of several elemental pollutants such as arsenic in national and
regional surveys had also been reported (Freitas et al., 1999). Van Herk et al. (2002) and
Aptroot and van Herk (2007) documented that the presence or absence and dominance of
a species or a group of species are known to provide valuable information about the
alteration in the air quality of an area due to air pollution or microclimatic changes.
Page | 24
Molnar and Farkas (2010) during their study proved that in addition to their role in lichen
chemotaxonomy and the systematic as well as biological roles, lichen secondary
compounds have several possible biological roles, including photoprotection against
intense radiation. These compounds are also important factors in metal homeostasis and
pollution tolerance of lichen thalli.
The impact of atmospheric pollutant on the integrity of cell membranes and chlorophyll
of lichen Ramalina duriaei which was transplanted from a relatively unpolluted site in
Israel to a highly polluted area for a period of 10 months was studied and the study
indicated that the electric conductivity parameter reflecting the integrity of lichen cell
membranes was found to express the cellular damage caused to lichen thalli transplanted
to a steel smelter and to oil refineries (Garty et al., 1993).
The general competence of accumulation of elements are from foliose to crustose and
then finally fruticose lichens. Most of the studies on accumulation of heavy metals like
Pb, Cu, Fe and Zn in lichens are more focused and little attention has been paid on other
trace elements such as As, Hg, Mn and Ag (Charlesworth et al., 2003). Ormrod (1984)
had linked automobile traffic in Los Angeles with the release of Pb, Zn, Cd, and Cu.
Nieboer et al. (1978) predicted that the accumulation of metals by lichen thalli is one of
the best studied aspects of lichen biology. Nyangababo (1987) observed a close
correlation between the distribution pattern of lichen species and the trace metal content
of the surrounding air.
The amount of total chlorophyll, chlorophyll a and chlorophyll b was inversely
proportional to the sulphur dioxide concentration (Le Blanc et al., 1976). Later,
Silberstein and Galun (1988) supported the views by claiming that chlorophyll content
and chlorophyll degradation are parameters that can be commonly used to assess the
impact of air pollution on lichens. Boonpragob (2000) also reported that chlorophyll in
lichens is very sensitive to changes in environmental factors including air pollution.
Purvis (2000) and Haffiner et al., (2001) reported that excessive levels of pollutants in the
atmosphere, in particular sulphur dioxide (S02) can alter the physiology and
Page | 25
morphology of sensitive species, ultimately killing them and thus changing lichen
community structure.
Bačkor et al., (2003) in a study reported that copper in high concentration can decrease
total carotenoid concentration in Trebouxia cell, however, no alteration in the total
carotenoid content was shown in tolerant species like lichens of the family Physciaceae.
The study was supported by Pawlik-Skowrońska et al. (2006) who indicated that copper
in elevated concentrations may supplement synthesis of carotenoid content.
Wiseman and Wadleigh (2002) documented that the presence of metals can act as
signature elements for other pollutants, and high sulphur levels in the lichen are reflective
of atmospheric sulphur pollutants. The use of lichens as indicators of air pollution has
been well studied in Europe and northern America (Pinho et al. 2004; Loppi and Frati,
2006; Thormann, 2006) however, little is known about air pollution and its effects on
lichen in Africa. Rai et al. (2011) also reported that lichens comprise a unique group
which are among the most significant indicators of environment and also are sensitive
towards habitat variation.
National scenario
In Indian context, use of lichens as bioindicators was initiated only in the late eighties
when Das et al. (1986) investigated the frequency of lichens in 25 streets of Kolkatta
(Calcutta) in accordance to the traffic load of the city and found out that the species and
population of lichens could be an indicator for determining the air quality of a particular
place. Das et al. (1986) reported the frequent occurrence (13.4% to 93.3%) of single
pollution tolerant species, Parmelia caperata (L.) Ach. on the roadside trees of the streets
withstanding heavy traffic load. Upreti et al., (2005) during a study on lichens of Indian
Botanical Garden, Howrah, reported the area was dominated with more tolerant crustose
lichens followed by foliose and fruticose lichens.
The use of lichens as biomonitors was adopted in different climatic zones of India by
several workers. (Dubey, et al., 1999; Nayaka et al., 2003; Bajpai et al., 2004, 2010; and
Upreti, 2014; Das et al., 2015).
Page | 26
Chettri et al. (1998) proved the interference of metals with the biosynthetic of chlorophyll
in addition to its part in lipid peroxidation processes in photosynthetic membranes. Upreti
and Shukla (2007) inferred that the most obvious signs of pollution damage to lichens are
bleaching of the thalli, caused by decomposition of chlorophyll as metallic pollutants are
known to disrupt the vital physiological processes. Shukla and Upreti (2008) studied the
stress physiology with relation to pigment content, chlorophyll degradation ratio,
carotenoid and protein content and revealed the existence of positive correlation with the
increase in pollution level. Nayaka and Upreti (2005) while studying the lichen flora of
Pune city, western India with reference to air pollution found that the streets/ sites mostly
in the outskirts having thick tree cover together with less traffic activity showed luxuriant
growth of lichens while the city centre with scattered trees and high traffic activity has
scarce or complete absence of lichens. Nayaka et al. (2005) also revealed the
accumulation of Cu, Ca and S in high concentration in Cryptothecia punctata a crustose
lichen collected the Arecanut trees in south India that were exposed to several sprays of a
fungicide Bordeaux mixture.
Bajpai et al. (2009) analyzed total arsenic contained in four different growth forms of
lichens growing on old monuments in the city of Mandav, Dhar district of Madhya
Pradesh. The accumulation of metals like Al, Cr, Fe, Pb and Zn in the lichen thalli can
enhanced the level of protein but suppressed the chlorophyll integrity (Bajpai et al.,
2009). Bajpai and Upreti (2012) inferred that few poleotolerant species such as
Phaeophyscia, Pyxine and Rinodina were evaluated for physiological response to
metallic, stress in the way of passive as well as active monitoring (Shukla and Upreti,
2008; Satya and Upreti, 2009; Bajpai and Upreti, 2012).
Regional scenario
Few sporadic studies on the use of lichens in biomonitoring the ambient environment was
done. A comparative study of different degree of disturbance in Cachar district of Assam
was done by investigating the pigment profile and chlorophyll degradation of Pyxine
cocoes lichen as the species has been inferred as a good mitigator of industrial fallouts
(Rout et al. 2010a). Daimari et al., (2013) also estimated heavy metal accumulation in
Page | 27
epiphytic lichens and their phorophytes of two characteristic areas of the Brahmaputra
Valley, Assam and revealed that the mean concentrations of the heavy metals were found
to be higher in lichens at areas situated near to the downtown area of the city and the
Brahmaputra River. Daimari et al., (2013) mentioned that estimation of heavy metal
accumulation in lichens offers an option to indirectly measure the concentration of heavy
metal in the atmosphere.
Lichens have been appreciated all over the world as the most sensitive indicators of
environmental conditions, no reports on use of lichens as biomonitor in checking the
ambient surrounding of Manipur is available except for the study on quick assessment
conducted in Imphal city to check the air quality by Pinokiyo et al., (2012).
2.3 Bioprospecting lichens
Lichen has a wide variety of use over the ages as food, medicine, feed for animal, as
dyeing stuff biomonitors and also in making perfumes, paints, fibres, fermenting agent
etc (Ingolfsdottir et al., 2000; Müller, 2001; Ingolfsdottir, 2002; Choudhary et al., 2005;
Stocker-Wörgötter, 2005). The multifarious uses of lichen are due to the production of a
great number of various secondary metabolites most of which occurred exclusively in
these symbiotic organisms (Boustie and Grube, 2005).
The distribution patterns of secondary metabolites in the lichen thalli are usually taxon
specific (Hawksworth, 1976). Lichen substances are usually classified according to their
biosynthetic origins and chemical structural features. Boustie et al., (2011) reported that
extraction yield as large as 1 to 25% of dried lichen materials can be rated and that the
composition can be characterized by one to three metabolites accumulated in the high
yield. Elix (2014) published a catalogue of standardized chromatographic data and the
biosynthetic relationships for lichen substances.
Hyvärinen et al., (2000) reported that the concentrations of secondary compounds in
some lichen species are higher in reproductive structures when compared with that of the
vegetative parts of the thallus. Lichens acts as light filters to shelter the photobiont from
Page | 28
excessive radiation (Gauslaa and Solhaug, 2001) or may have antibiotic properties to
protect against microbial degradation (Emmerich et al., 1993) or may be involved in
maintaining the symbiotic equilibrium (Kinraide and Ahnadjian, 1970; Huneck, 2003).
Molnar and Farkas (2010) documented that lichen secondary compounds have several
possible biological roles, including photoprotection against intense radiation in addition
to their role in lichen chemotaxonomy and the systematic as well as biological roles.
The medicinal use of foliose lichens Evernia furfuracea (L.) Mann or Parmeliaceae was
the first report using lichen as a drug. The “Doctrine of Signatures‟‟ formed the basis of
phyto-therapeutics in traditional systems of medicines like Traditional Indian medicine
(TIM) or Ayurveda, Traditional Chinese Medicine (TCM), and Western Medical
Herbalism. Crockett et al., (2003) and Rankovic et al. (2007) reported the use of lichens
as medicine in treating wounds, stomach diseases and whooping cough in America and in
Europe. Screening tests with lichens have demonstrated the frequent occurrence of
metabolites with antibiotic, antimycobacterial, antiviral, anti-infammatory, analgesic,
antiproliferative, antipyretic, and cytotoxic properties (Bucar et al., 2004; Omarsdottir et
al., 2007; Guo et al., 2010; Liu et al., 2010).
Usnic acid have been reported as the most investigated lichen secondary metabolite as it
showed tumour-inhibitory activity for lung carcinoma (Kupchan and Kopperman, 1975).
The search for new potential anti-cancer compounds has involved several lichen
metabolites (Ding et al., 1994; Yamanoto et al., 1995). Extracts of Parmelia
austrosinensis and Parmelia praesorediosa had glucosidase inhibitory activities (Lee and
Kim, 2000). Inhibition of glycosylation is believed to affect melanin biosynthesis in
human melanoma cells. Bianthraquinone glycosides, colleflaccinosies isolated from
Collema flaccidum (Ach.) Ach. (Collemataceae) collected from Israel and Russia, were
reported to have antitumor activity (ReZanka and Dembitsky, 2006).
Omarsdottir et al. (2007) found out that heteroglycans and a beta-glucan isolated from
Thamnolia vermicularis var. subsliformis were tested for in vitro immune modulating
activity and reported to have various influences on the immune system. The
hypoglycemic activity of the lichen Cladonia humilis is reported in a study conducted by
Page | 29
Liu et al., (2012) and the anti diabetic potentials of Cladonia humilis was also reported
for the first time.
Lichens are also known to produce unique characteristic anthraquinone derivatives,
which are absent in higher plants (Eichenberger, 2007) and are ingredients of many
medicines of plant origin since they possess a range of biological activities, including
anti-bacterial, anti-tumorous, purgative astringent, anti-viral, antioxidant and antifungal
(Yen et al., 2000; Manojlovic et al., 2008).
The antibacterial properties of lichen extracts were discovered when 27 of the 42 lichen
species studied were found to produce compounds that were effective against
Staphylococcus aureus or Bacillus subtilis, four produced compounds that inhibited
Proteus vulgaris or Alcaligenes fecalis but none of the tested lichen extracts inhibited
Escherichia coli (Burkholder et al., 1944).
Usnic acid is well known for its antibiotic properties (Cocchietto et al., 2002) and
incorporation of usnic acid into medical devices inhibits bacterial biofilm formation on
polymer surfaces (Francolini et al., 2004). Saenz et al., (2006) reported that usnic acid
was the most effective against gram positive bacteria while testing the antimicrobial
activity of ten macro lichens collected from Spain. The parietin and anthraquinone
isolated from methanol extract of Caloplaca cerina (Ehrh.ex Hedwig) Th.Fr. has also
been reported to have significant activity. Mitrović, et al., (2011) evaluated the
antioxidative, antimicrobial and antiproliferative potentials of the methanolic extracts of
five lichen species, Parmelia sulcata, Flavoparmelia caperata, Evernia prunastri,
Hypogymnia physodes and Cladonia foliacea. Amongst the five lichen extracts, the
extract of Hypogymnia physodes which has the highest phenolic content showed the
strongest 2, 2-dipheny1-1-picrylhydrazy1 (DPPH) radical scavenging. Further, it was
reported that the lichen antimicrobial activity was more pronounce in the extract of
Hypogymina physodes and Cladonia foliacea.
Page | 30
National Scenerio
Lichens have been household items of Indian since ancient times as medicines and in
various cultural events (Kumar and Upreti, 2001). The first record of lichens, being used
as medicine in India was reported in Atharveda (1500 B.C) as „Shipal‟ and in
Ayurveda, the ancient system of medicine of India by the vernacular name „Chharila‟
as aphrodisiac (Lal and Upreti, 1995; Kumar and Upreti, 2001). The Indian drug
chharila (Parmelia chinense, P. sancti-angeli and P. peforatum) were used as diuretic
and as liniment for headache and powder to help wounds heal. Parmelia sancti-
angeli in Central India to treat Tinea (ringworm) like disease was well documented.
Reports on used of Heterodermia diademata for cuts and wounds n Sikkim were
available (Saklani and Upreti, 1992). Kumar et al. (1996) documented that Parmelia
nepalense is used in Nepal in the treatment of toothache and sore throat while as
Thamnolia vermicularis is used as antiseptic in Western Himalayas (Negi and kareem,
1996). Reports on extensively used of parmeloid lichens are in traditional medicine to
treat diseases and disorders like headache, skin diseases, urinary trouble, boils,
vomiting, diarrhea, dysentery, heart trouble, cough, leprosy and as blood
purifier have been reviewed (Chandra and Singh, 1971; Kumar and Upreti 2001). Rout et
al., (2005) had also described the ethno medicinal use (removal of kidney stones) of a
common lichen Cladonia rangiferina, dimorphic lichen from the alphine regions of West
Kameng district of Eastern Himalaya. The proximate composition, antifungal and
anthelmic activity of the methanolic extracts of macrolichen Ramalina hossei collected
from the forest area of Bradra wildlife sanctuary, Karnataka, India could be effectively
used in controlling the opportunistic fungal and helminthic infections (Kumar et al.,
2010). The study also highlighted the importance of R. hossei in terms of its rich
carbohydrate, protein, crude fibre and mineral composition, justifying the possibility in
reducing malnourishment problems.
Lichens contain many characteristic aromatic compounds with known therapeutically
potentials (Upreti and Chatterjee, 2007; Verma et al., 2008). Jayapraksha and Rao (2000)
described the moderate antioxidant activity of the phenolic constituents such as methyl
Page | 31
orsenillate orenillic acid, atranorin and lecanoric acid of the lichen Parmotrema
stuppeum.
Antibiotic and antifungal activity screenings of Indian lichens have been intiated by
Shahi et al., (2001); Balaji and Hariharan (2007); Sati and Joshi (2011). Gayathri (2012)
also discussed the importance of lichens in inhibiting various types of human pathogens
in addition to the chemical composition and pharmacological activities. Gupta et al.,
(2007) evaluated the antimycobacterial properties of nine lichen extracts against
Mycobacterium tuberculosis and found out that the extracts prepared showed 90%
inhibition and that the methanolic extract was more susceptible that the ethanollic extract.
A study on antibacterial activity of the extract of Roccella belangeriana against 12
bacterial strains showed maximum antibacterial activity in chloroform extract against
Enterococci sp. and minimum activity in ethyl acetate extract against Klebsiella
pneumonia, Enterococci Sp., Salmonella sp. and Shewanella sp. (Karthikaidev et al.
2009). Swathi et al. (2010) also evaluated the antifungal, antibacterial and anthelmintic
activity of Everniastrum cirrhatum, a foliose lichen that grows luxuriantly in tropical
Himalayas, central India and higher altitudes of southern India and reported that the
extract showed antibacterial activity against both gram positive and gram negative
bacteria, antifungal activity against Aspergillus niger and A. fumigants and anthelmic
activity against Indian earthworm model.
The cardioovascular protective, antioxidative and antimicrobial properties of natural
thallus of lichen Usnea complanata has been evaluated and according to it, a strong
correlation was shown between the cardiovascular protective and antioxidant properties
of U. complanata and the total polyphenolic content present in the extract and that the
ethyl acetate extract of U. complanata was found to be most efficient than any other
extracts against all the tested bacteria (Behera et al., 2011). Behera et al., (2012)
extended the work on the cardiovascular protective and antioxidant properties of isolated
and purified usnic acid and psoromic acid of U. complanata.
Page | 32
2.4 Nanoparticles
Nanotechnology, a technology which covers the production of nanoparticles of variable
sizes, shapes, chemical compositions and controlled disparity, has become an interesting
area of research with its application in different fields such as electronics, biotechnology,
chemical and biological sensors, DNA labeling, drug delivery, cosmetics, coatings and
packaging (Mikami et al., 2013). Traditional methods for synthesizing metallic
nanoparticles were often opted out and biological synthesis of metal nanoparticles have
been widely accepted due to the environmentally acceptable solvent system, eco-friendly
and the elimination of high pressure, energy, and toxic chemicals in the traditional
synthetic methods (Goodsell, 2004).
Plant species including microorganisms such as bacteria, fungi and algae are considered
as environmentally benign reservoirs for the production of nanoparticles (Gardea-
Torresdey et al.,2002; Gericke and Pinches, 2006). Gold in nanoscale display novel
properties and have diverse activities that make it appropriate for therapeutic use and
board application in nanobiotechnology (Kim et al., 2004; Sperling et al., 2008).
The biosynthesis of gold nanoparticles by plants such as lemongrass (Shiv, 2004), tea
(Nune, 2009), Terminalia catappa (Ankamwar, 2010) were reported. Parida et al., (2011)
also reported the synthesis of cost effective and environment friendly gold nanoparticless
using onion (Allium cepa) extract as the reducing agent. Das et al. (2012) also
synthesized gold nanoparticles using leaf extract of Amaranthus spinosus and further
studied the optical properties of the synthesized gold nanoparticles. Most recently,
biosynthesis of gold nanoparticles was accomplished via reduction of an aqueous
chloroaric acid solution using the dried biomass of on edible freshwater epilithic red
alga, Lemanea fluviatilis (L) C.Ar., as both reductant and stabilizer (Shrama et al., 2014).
Biosynthesizing of novel metal nanoparticles using lower plants such as lichens have
been accomplished very rarely. Shahi and Patra (2003) reported the synthesis of bioactive
nanoparticle from lichen biomass through in vitro culture for the first time and also the
use of the formulated bioactive nanoemulsion for testing in vitro bioactivity against
human pathogenus fungi. In yet another study, it was revealed that Parmotrema
Page | 33
praesorediosum could be used to synthesis silver nanoparticles due to the presence of
two unique aliphatic acids ie, (+) – praesorediosic acid [ 2-(14‟- carboxytetradecy1)-4-
methy1-5-oxo-2,5-dihydrofuran-3-carboxylic acid] and protopraesorediose acid [ 2-(14‟-
carboxytetradecy1)-4-methylene-5-oxo-2,5-tetrahydrofuran-3-carboxylic acid] and that
the synthesized AgNPs showed potential antibacterial activity against gram- negative
bacteria (Mie et al., 2014). Singh et al. (2014) also developed an antimicrobial herbo-
metallic colloidal nano-formulation from Swarna nanoparticles containing and
polyphenols rich Usnea longissima extract and evaluated its antiquorum sensing property
against Streptococcus mutans.
Though not quite exhaustive, the present literature review highlights the current status of
some selected aspects of lichen research. Combined with what has been discussed in the
introduction ( Chapter 1), this chapter forms the basis of present research undertaken
from a relatively under-explored area.