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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),

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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

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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

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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).

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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

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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

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(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).

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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

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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

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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;

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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.

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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

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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).

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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

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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

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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

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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.

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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

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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.

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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

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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.