Volume 1, Issue 3 of Tropical Plant Research

www.tropicalplantresearch.com 1 Published online: 31 October 2014

ISSN (E): 2349 1183 ISSN (P): 2349 9265

1(3): 0112, 2014

Research article

Phenology, growth and survival of Vatica lanceaefolia Bl.: A

critically endangered tree species in a moist tropical forest of

Northeast, India

Mrigakhi Borah and Ashalata Devi*

Department of Environmental Science, Tezpur University, Tezpur, Sonitpur, Assam, India

*Corresponding Author: [email protected] [Accepted: 28 September 2014]

Abstract: An attempt has been made to unravel the major phenophases, seedling survival and

growth of Vatica lanceaefolia, a critically endangered tree species in two different micro sites of

Hollongapar Gibbon Wildlife Sanctuary, Assam. The study was carried out for a period of 24

months to investigate various phenophases with respect to seasonal variations of the year and, to

understand the growth and survival of the seedlings in two micro sites (gap and understory) in

relation with the prevailing meteorological parameters of the study area. Leaf flushing was

observed twice in a year in the month of December and May, while flowering and fruiting occurs

during pre-monsoon season (April and May). The seedlings showed better survival in gap (66.6%)

compared to the understory (46.6%) and relative growth rates of the seedlings in terms of height

and collar diameter varied significantly across the months and also between the micro

environmental conditions of the two micro sites (P

Borah & Devi (2014) 1(3): 0112 .

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Phenology of vegetative phases is important, as cycles of leaf flush and leaf fall are intimately related to

processes such as growth, plant water status and gas exchanges (Reich 1995). Phenological study is also

essential for seed procurement of plant species. The knowledge on phenology of plants has helped to understand

the influence of phenological events on feeding, movement patterns, and sociality of insects, birds and mammals

(Foster 1982a, Prasad 1983, Coates-Estrada & Estrada 1986). The timing of flowering in plants can serve as an

isolating mechanism in plant speciation (Newstrom et al. 1994). The timing of flowering and fruiting in tropical

trees has been attributed to edaphic, climatic and biotic factors and photoperiod, temperature and soil moisture

have been recognized as the main environmental cues for leafing and flowering (Rathcke & Lacey 1985). In

most tropical forests, variation in rainfall is suggested to be the most significant climatic factor that influences

the phenology of flowering and fruiting (Foster 1974, Hilty 1980, Borchert 1983).

India with a wide range of variation in climate, altitude and physiography exhibits enormous variation in the

life cycle of plants of different regions (Koul & Bhatnagar 2005). Several studies on phenology (Boojh &

Ramakrishnan 1982, Shukla & Ramakrishnan 1982, Ralhan et al. 1985, Bhat 1992, Bajpai et al. 2012, Kaur et

al. 2013) were made in different forest types of India. In recent years phenological studies on some forests of

Assam have been reported by few workers (Nath 2012, Devi & Garkoti 2013, Barman et al. 2014, Devi et al.

2014). However, studies on phenology of tropical moist semi evergreen forest and species specific in particular

of North East India, particularly in Assam have been little worked out.

An understanding of the population status and regeneration behaviour is a pre-requisite for developing

conservation strategies for the threatened species (Upadhaya et al. 2009). Successful regeneration of a species in

nature depends on its ability to withstand disturbance stress that plays a key role in seedling survival and

establishment (Rao et al. 1990). Seedling survivorship relies on many factors, both abiotic and biotic

(Karst et

al. 2011). The process of seedling growth and development of forest trees largely depends on gaps/canopy

openings in the forest created due to natural disturbance or seedling establishment barriers such as topography

(Koide et al. 2011), thus influences the regeneration and species composition of the forest (Khumbongmayum et

al. 2005). A canopy gap is defined as an area opened by the removal of canopy trees, in which most of the living

plants were < 5 m tall and < 50 % of the height of surrounding canopy trees (Runkle 1982). Gap dynamics has

been described by many researchers in tropical (Brokaw 1985, Lawton & Putz 1988, Khumbongmayum et al.

2005, Sapkota et al. 2009, Arihafa & Mack 2012) and sub-tropical forests (Barik et al. 1992, Arunachalam &

Arunachalam 2000, Griffiths et al. 2007), and are being considered as a process capable of influencing the

structure of plant communities, enhanced diversity of forest systems, as it expands environmental heterogeneity,

and chances for the growth of tree species (Yamamoto 2000). Many workers reported better growth and survival

of tree seedlings in tropical (Augspurger 1984) and subtropical (Khan & Tripathi 1991, Rao et al. 1997) forest in

areas with more sunlight and there are evidences of fast growth and better survival of dipterocarp seedlings in

gap compared to understory (Tuomela et al. 1996, Kuusipalo et al. 1997, dOliveira & Ribas 2011). These

studies have suggested gap dynamics as an alternative management technique for the degraded and over- logged

Dipterocarp forests. Studies on species-specific seedling growth and survival in northeast India is sparse with

only a few documentations (Bharali et al. 2012, Saikia & Khan 2012a, Saikia & Khan 2012b).

The present study was carried out to understand the major phenological changes and, seedling growth and

survival of V. lanceaefolia in the study area. The study examines the spatial and temporal changes of

phenophases of the plant species and seasonal variation of seedling growth and survival in different micro-sites.

MATERIAL AND METHODS

Study area

The study was conducted for two years (2010-2012) in Hollongapar Gibbon Wildlife Sanctuary (HGWLS),

which is situated in Mariani, Jorhat District of Assam, India. It covers an area of 20.98 km2 and situated at

2640" to 2645" N and 9420" to 9425" E and is located in the south bank of the Great Brahmaputra river

system at an altitudinal gradient of 100120m above msl. The forest type of the sanctuary is Eastern Alluvial

Secondary Semi Evergreen Forest (1/2/2B/2S2) (Champion & Seth 1968) under moist tropical forest of India,

dominated by plants namely, Dipterocarpus macrocarpus, Vatica lanceaefolia and Mesua ferrea. The sanctuary

is divided into five compartments by the forest department. Continuous pressure by the people of fringe area

mainly in the form of cattle grazing, fishing, illegal felling of trees and fuel wood collection have threatened the

flora and fauna of this sanctuary.

Climate and soil type

Borah & Devi (2014) 1(3): 0112 .


The climate of HGWLS is seasonal with monsoonic pattern of rainfall having four seasons winter

(December to February), pre-monsoon (March to May), monsoon (June to September) and post-monsoon

(October to November). Rainfall data were collected from India Meteorological Department while relative

humidity and temperatures were recorded with the help of a pocket weather station (Kestrel 4000 NV). Winter is

cool and temperature goes down up to 7 C and maximum temperature was recorded 32.4 C in the monsoon

season. Relative humidity ranged from 4095 % during the study period (Fig. 1).

Figure 1. Meteorological parameters of the study area during the study period (July 2010July 2012).

Different micro-environmental variables such as light intensity and edaphic characteristics of the two micro

sites i.e. gap and understory were determined during the study period 20102012. Light intensity was measured

using digital light meter (Extech EasyViewTM

30). A total of 20 soil samples, 10 each from gaps and understory

were collected from the depth of 10 to 15 cm after removing litter accumulation and physicochemical

characteristics of the soil was analysed in the laboratory of Department of Environmental Science, Tezpur

University, Assam. Soil type of the sanctuary is sandy clay loam and the surface soil is largely covered by litter

fall. Light intensity and physicochemical parameters of soil of two micro sites of the study site are given in

Table 1.

Table 1. Physico-chemical parameters of soil and environmental variables recorded in the understory and gap

of HGWLS.

Variables Gap Understory

Light intensity (mol m-2

s-1

) 1235.4-2993.03 52.29-122.60

Soil texture Sandy Clay Loam Sandy Clay Loam

Sand (%) 67.47 68.83

Silt (%) 10.04 9.58

Clay (%) 22.49 21.59

Bulk density (g/cm3) 1.1 1.23

Water holding capacity (%) 49.07 47.22

Soil pH 4.9 5.2

Conductivity (mS/cm) 0.2744 0.296

Available N (%) 0.0109 0.031

Available P (ppm) 6.06 6.01

Available K(ppm) 45.88 46.12

Organic Carbon (%) 1.548 2.12

Organic matter (%) 2.6438 3.82

Study species

Vatica lanceaefolia is a middle canopy evergreen tree species under the family Dipterocarpaceae (Fig. 2A).

The species is distributed randomly in all the five compartments of the sanctuary. The density of the species

inside the sanctuary is 227 individuals per hectare (Sarkar & Devi 2014). V. lanceaefolia is largely collected by

Borah & Devi (2014) 1(3): 0112 .


villager inhabitant in the fringe of the wildlife sanctuary due to its good quality firewood. Large individuals

(girth > 40 cm) of the species are also illegally cut down by the people of surrounding villages for commercial

purpose. During the study period, cut stumps of the species were found to be highest in compartment no. 1 and 5

having 4 and 3 individuals ha-1, respectively.

Figure 2. Vatica lanceaefolia Bl.: A, Adult Tree; B, Seedling; C, Flowers; D, Germinated seeds on the forest floor.

Phenological investigations

Preliminary investigations on major phenological events of V. lanceaefolia were carried out for a period of

two consecutive years (April 2010-March 2012) in Hollongapar Gibbon wildlife sanctuary. A total of twenty

five adult plants (having gbh > 40 cm) with uniform canopy coverage were tagged using Aluminium sheets and

plastic thread in five different compartments of the study site having five individuals in each compartment for

phenological investigation. Monthly observations for phenological changes were made for six major

phenological phases viz., leaf abscission or senescence of leaves, leaf flushing, flowering, fruiting, and dropping

of fruit and vegetative growth. The phenological characteristics are reported as per Newstrom et al. (1993 &

1994) and phenophases were represented with the help of a phenogram.

Survival and growth of seedlings

Two micro sites namely understory and gap were selected for the study of seedling survival and growth of V.

lanceaefolia in HGWLS. The area of gap was measured using the equation for the area of an ellipse, after

measuring the longest axis and its perpendicular shorter axis by laying down long meter tapes (Sapkota et al.

2009). A gap of 942.48 m2 in size inside the forest area located at 264040.2N and 942053.4E were selected

for the purpose of the study. Thirty seedlings of uniform size and shape within height range of 9 to10.5 cm

without any physical damage or herbivory attack were selected in each of the understory and gap (Fig. 2B). To

Borah & Devi (2014) 1(3): 0112 .


analyse the temporal variation of growth of seedlings, plant height (cm) and collar diameter (cm) of each tagged

seedling were measured and recorded at monthly intervals for a period of two years (July 2010-June 2012). The

Relative Growth Rate (RGR) in terms of height (RGRH) and collar diameter (RGRD) was calculated as per the

formula (Hunt 1982).

RGR (tn-1-tn) = lnS(tn)-lnS(tn-1)/ tn-tn-1

Where, S is the plant size, i.e. height (cm) or collar diameter (cm) and t is the time (months).

Seasonal variation for RGRH and RGRD in gaps and understory seedlings of the study site was analysed by

one-way ANOVA and significance in variation of the RGRH and RGRD between the seedlings in gap and

understory was tested using t-test. The correlation between few meteorological parameters viz. relative

humidity, rainfall and average temperature with the relative growth rates of seedlings in both understory and

gaps were analysed. All of these analyses were performed in SPSS software version 16.0.

RESULTS

Phenological observations

Vatica lanceaefolia did not show any significant difference among the phenological events from year to year

during the two years of consecutive study. It was also observed that the meteorological parameters recorded

were more or less same during the two years observation (Fig. 1). The two years study depicts that, leaf

abscission accompanied by large scale leaf flushing of V. lanceaefolia takes place in the month of December.

Flowering takes place once in a year in the month of April, fruit initiation takes place in May with fruit

maturation in late June and dropping of fruit takes place in the month of July. From August to November the

plant species did not show any major event of phenology and it was considered as vegetative growth (Table 2).

In late July, germination of V. lanceaefolia takes place in the forest floor.

Table 2. Monthly phenophases of Vatica lanceaefolia recorded during the study period.

Study years Apr May Jun Jul Aug Sept Oct Nov Dec Jan Feb Mar

2010-2011

20112012

Abbreviations: 1=Leaf abscission, 2=Leaf flushing, 3=Flowering, 4=Fruiting,

5=Dropping of fruit and 6=Vegetative growth.


Seedling survival in two micro sites

J ul Nov Mar J ul Nov Mar J ul

0

50

60

70

80

90

1 00

Seed

ling

surv

ival

(%

)

Months

Gap

Understory

Figure 3. Survival of seedlings (%) of Vatica lanceaefolia in understory and gap during the

study period.

At the end of the study period, the seedling survival percentage of V. lanceaefolia in the two micro sites viz.

understory and gaps was recorded 46.6 % (N=14) and 66.6 % (N=20), respectively. The seedling survival was

comparatively high in gap compared to the understory (Fig. 3). In the first year observation, the mortality rate of

Borah & Devi (2014) 1(3): 0112 .


seedlings in gap was 23.33 % while in the following second year observation mortality rate was reduced with

13.04 %. Similarly, seedlings of understory also showed higher mortality rate of 30 % in the first year of

observation compared to 26.32 % in the second year of observation. Seedling mortality was high in the month of

January and February, which experience the cool and dry winter season in both the study years.

Variation in relative growth rates of seedlings between two micro sites

Relative growth rates in terms of height (RGRH) and collar diameter (RGRD) of the seedlings recorded in

both the micro sites during the study period shows higher increment during the month of May and August which

corresponds to pre-monsoon and monsoon season and less during February (winter season) and November

(post-monsoon season). However, RGRH and RGRD of seedlings exhibit different increment between the gaps

and understory with response to seasonal changes. RGRH of understory seedlings shows slightly higher growth

rate during winter and post-monsoon compared to the seedlings in gap (Fig. 4).

Figure 4. Relative Growth Rates of Vatica lanceaefolia seedlings recorded in understory (U) and gap (G): A, Height

(RGRH); B, Collar Diameter (RGRD).

RGRH (t=4.362, df=11, P=0.001) and RGRD (t=5.575, df=11, P=0.000) of seedlings varied between gap

and understory and the difference was highly significant. RGRH and RGRD of seedlings of V. lanceaefolia in

both the micro sites also varied significantly (P=0.000) across the months {RGRH(U), t=5.41, df=23;

RGRH(G), t=4.794, df=23; RGRD(U), t=4.450, df=23; RGRD(G), t=4.552, df=23}.

It was observed that relative growth rate in terms of height (RGRH) in both understory (U) and gap (G)

exhibited positive correlation with rainfall, relative humidity and average temperature of the study area during

the study period (July 2010Jun 2012). Relative growth rates in terms of collar diameter (RGRD) in understory

(U) and gap (G) also showed little correlations with these meteorological parameters (Table 3).

Table 3. Correlations of RGRH and RGRD of seedlings of understory and gaps with meteorological parameters.

Data from July 2010June 2011 Data from July 2011June 2012

RF RH AVT RF RH AVT

RGRH(U) R=0.637* R=0.602* R=0.687** R=0.786** R=0.544* R=0.609*

RGRH(G) R=0.702** R=0.665** R=0.781** R=0.686** R=0.560* R=0.675**

RGRD(U) R=0.548* R=0.548* R=0.482ns

R=0.452ns

R=0.543* R=0.416ns

RGRD(G) R=0.521* R=0.349ns

R=0.197ns

R=0.673** R=0.395ns

R=0.521*

RF=Rainfall, RH=Relative humidity and AVT =Average temperature

*significant at the 0.05 level

**significant at the 0.01 level ns

not significant

Borah & Devi (2014) 1(3): 0112 .


Absolute height and collar diameter of Vatica lanceaefolia seedlings in gap and understory

At the end of the 12 months observation, the absolute height of the tagged seedlings of V. lanceaefolia

reached 20.70.303 cm and 23.90.259 cm in understory and gap, respectively whereas, collar diameter of the

seedlings reached 1.30.055 cm and 1.60.089 cm, respectively for understory and gap. But the difference in

absolute height of the seedlings in understory and gap was not significant (P>0.05). At the end of the two years

study, the absolute height of the tagged seedlings reached 32.22.25 cm and 35.70.72 cm in understory and

gap, respectively. Correspondingly, collar diameter of the seedlings reached 30.29 cm and 3.60.28 cm,

respectively for understory and gap. Variations in absolute height (t=58.428, df=14, P=0.000) and collar

diameter (t=39.884, df=14, P=0.000) of seedlings of V. lanceaefolia between the two micro sites was highly

significant at the end of two years of observation.

DISCUSSIONS

Phenological observations

From the present study it was revealed that, V. lanceaefolia is an annual flowering plant with brief flowering

(< 1 month) duration (Newstrom et al. 1993 & 1994). Bud initiation in V. lanceaefolia takes place after the first

shower of monsoon or in mid-April and flower fully opens in the month of May. White flowers of the plant

species (Fig. 2C) bear a very mild, pleasant fragrance. Flowering takes place almost at the same time in all the

inflorescences of the plant. Occurrence of peak flowering and fruiting records in the months of April to May

corresponds with the increased temperature during the pre-monsoon season or the summer. Increasing day

length, soil moisture and temperature may have induced flowering during warm pre-monsoon period (Foster

1974, Hilty 1980, Rathcke & Lacey 1985). Regular flowering in some tropical deciduous trees after the spring

equinox during MarchJune has been reported by many workers (Felger et al. 2001, Singh & Kushwaha 2006).

After 25 days of flowering fruit initiation takes place as the monsoon rain starts and earlier studies also

suggested that the seasonal availability of water is the primary determinant of fruiting (Foster 1974, Borchert

1983, Bach 2002). Fruit maturation takes place in June during the monsoon period. The need of high moisture

level for the proper development of fleshy fruits has been reported by Zahner (1968), and it was also showed

experimentally that the shortage of soil moisture reduces the rate of enlargement and final size of fruits. Seeds of

V. lanceaefolia germinates without any dormancy period within 6-10 days of dropping, in late July which was

favoured by the sufficient availability of soil moisture content due to heavy precipitation and prevailing warm

temperature (Fig.2D). This relationship of germination with availability of soil moisture has also been supported

by several earlier studies (Foster 1982b, Shukla & Ramakrishnan 1982, White 1994, Bach 1998). In relation to

temperature, genera Vatica are known to germinate at temperatures above 14C (Yap 1981). In general seedlings

of dipterocarps germinate quickly in warm and moist climate (Tompsett 1986).

Flushing and leaf production completes towards the end of the dry season, before the onset of rains. Leaf fall

occurs when temperature declines and day length becomes short during winter which is also supported by earlier

studies (Shukla & Ramakrishnan 1984, Bhat 2001). There are several reports of maximum leaf-fall during the

driest period of the year in different tropical forest types (Richards 1952, Frankie et al. 1974, Opler et al. 1980,

Liberman & Liberman 1984). During dry season leaf abscission may be attributed to avoid water stress. It was

found that leaf flushing and leaf fall in V. lanceaefolia requires low temperature (2025C) and low relative

humidity (4050 %). In February the plant bears completely new leaves in its branches. This has also been

shown for other seasonal tropical forests (Boaler 1966, Frankie et al. 1974). After maturation of leaves, heavy

insect infestation is observed during the study period (personal observation). Studies have shown that seasonal

peaks and depressions for leaf flush and leaf fall are quite common in tropical rain forests with pronounced dry

period (Kramer & Kozlowski 1960, Fogden 1972). In tropics emergence of leaves peaked either in dry season

(Frankie et al. 1974, Whitmore 1984) or in the wet season (Fogden 1972, Proctor et al. 1983). Leaf flushing

during dry season probably permit renovation of the canopy before the onset of monsoon, so that the plant

becomes able to take full advantage of the rainy season to produce and store nutrients for their growth and

development. A small scale of leaf flushing observed in the month of May during the second year of observation

indicates minor difference in phenological events during the two year of study periods. However, such slight

variation could not interpret any remarkable changes in phenological events of the species and it may be stated

that the two year phenological observation of V. lanceaefolia reveals more or less similar pattern of phenophase

which corresponds with the recorded meteorological parameters.


Borah & Devi (2014) 1(3): 0112 .


During the two years of seedling survival and growth study, seedling mortality was recorded highest both in

understory and gap during the cold dry winter season (December to February) which resulted in sudden decline

in the survival percentage of the seedlings in the month of March in both the study years (Fig. 3). Large number

of mortality of seedlings during the winter season may be due to the detrimental effect of soil moisture stress on

the seedlings which has been stated by many workers (Khan et al. 1986, Kikim 1999, Khumbongmayum et al.

2005). From June, with the onset of monsoon and increase in soil moisture content, survival rate of the seedlings

was stabilized. Increase in survival rate of seedlings during the wet season is reported by various researchers

(Tompsett 1986, Lieberman & Li 1992, Bharali et al. 2012). Lower mortality rate recorded in the second year

observation than the first year observation may be attributed due the establishment of the seedling towards the

preliminary stage of sapling.

From the present study it was found that, RGRH, RGRD and absolute height of seedlings of V. lanceaefolia

is affected by different micro-environmental conditions and the seedling survival was favourable in gap (66.6

%) compared to the understory (46.6 %). Better growth and survival is recorded in a large number of plant

species in gaps compared to understory by many workers (Brokaw 1985, 1987, Welden et al. 1991, Nagamastu

et al. 2002). Higher light intensity and the prevailing micro-environmental conditions in gap may have

influence in the better growth rates of seedlings of V. lanceaefolia compared to the understory (Table 1). The

effect of light (Burton & Mueller-Dombois 1984, Connel et al. 1984) and temperature (Sorenson & Ferrel

1973) in regulating the growth of tree seedlings in tropical forests has been reported earlier by many workers.

Seasonal variability in growth response to light environment is an important parameter to determine the growth

of subtropical tree species (Khumbongmayum et al. 2005). Growth in terms of height and collar diameter of the

seedlings increased in both understory and gap during pre-monsoon and monsoon period probably because of

the rainfall, as it shows significant positive correlation with the rainfall of the study area during the study

period, however, growth rate decreases during cold dry seasons from November to February (post-monsoon and

winter) (Fig. 4). These may be attributed to the high moisture content in soil along with the high surface

temperature. The peak seedling growth during rainy season may be because of the increased availability of

nutrients in soil due to rapid decomposition of litter on the forest floor and because of the higher moisture

content of the soil (Mueller-Dombois et al. 1980, Khumbongmayum et al. 2005). It was observed that, relative

growth rates in terms of height and collar diameter of the seedlings in understory and gap also increases with

the increase in relative humidity during the monsoon period. Growth performance was highest in the months of

April to September with higher relative humidity and least in the months of November to February with lower

relative humidity. Growth reduction in plants due to low relative humidity of the air is reported earlier (Grantz

1990).

Prevailing average temperature of the study area also exhibited positive correlation with the seedling growth

performance. This reveals that, seedling growth of V. lanceaefolia is largely influenced by rainfall, relative

humidity and average temperature of the study area. It can be concluded that, seedling growth of V. lanceaefolia

shows better in gaps and growth rate increases with increase in soil moisture regime, ambient temperature and

rainfall during the summer monsoon season.

CONCLUSIONS

The present study reports the timing of occurrence of different phenological phases of Vatica lanceaefolia,

an annual flowering plant. Senescence of old leaves occurs with the onset of large scale leaf flushing as a

simultaneous process in the cold dry winter months. Flowering and fruiting occurs once in a year in pre-

monsoon season. Dropping of mature fruit takes place in late July and correspondingly germination of seeds

starts on the forest floor. The study also reveals that, seedling growth of V. lanceaefolia is significantly affected

by different micro-environmental conditions in terms of their survival and growth parameters. Significantly

higher growth performance was observed in the seedlings growing in gap area compared to the understory

during the study period in HGWLS. Thus, plantation of V. lanceaefolia seedlings in the gaps or in open areas

will be a fruitful measure to multiply the number of this critically endangered plant species in their habitat.

Germination showed dependency on water availability in the soil as it starts in the rainy season without any

dormancy period. Monthly relative growth rate (RGR) in terms of height and collar diameter indicates

dependency of the species on wet season as growth rates were found higher during the rainy hot months

compared to the cool dry months. The long rainy season from April to September (pre-monsoon and monsoon)

during the study period had a positive impact on the growth and development of seedlings in both the micro

sites, which was associated with the major changes in the phenological events of the plant.

Borah & Devi (2014) 1(3): 0112 .


Presently the sanctuary harbours a good density of V. lanceaefolia, but continuous anthropogenic pressure

exerted in terms of illegal cutting and felling for the purpose of firewood has emerged as a serious threat to the

survival of this species. So, possible measures should be undertaken to control the illegal logging of this species

by the fringe village people and proper strategies should be adopted to conserve the plant and multiply its

number in the study area in particular and other similar habitats of the species in northeast India in general. This

investigation on phenological characteristics and survival and growth of seedlings on this species is a pioneer

study and data of the present study may be helpful not only in the formulation of conservation strategies but also

in implementing further research aspects of this species viz. reproductive phenology, chemical analysis, genetic

improvement, etc.

ACKNOWLEDGEMENTS

The authors are thankful to the Principal Chief Conservator of Forests (Wildlife), Basistha, Guwahati,

Assam, for his kind permission to carry out the research work in HGWLS. Sincere thanks to forest officials of

Meleng Beat Office, HGWLS especially, Mr. Daben Borah, for his kind assistance during the entire field work.

We also thank Dr. Manoranjan Nath, Dr. Rajeev Basumatary and Dr. Gitamani Dutta for their valuable

suggestions and help.

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www.tropicalplantresearch.com 13 Published online: 31October 2014

ISSN (E): 2349 1183 ISSN (P): 2349 9265

1(3): 13 15, 2014

Research article

Pogonatum perichaetiale subsp. thomsonii (Mitt.) Hyvnen -

An uncommon species from western Himalaya

Vinay Sahu and A.K. Asthana*

Bryology Laboratory, CSIR-National Botanical Research Institute Lucknow- 226 001, India

*Corresponding Author: [email protected] [Accepted: 10 October 2014]

Abstract: The present study deals with the investigation of Pogonatum perichaetiale subsp.

thomsonii from Watan Village, Pithoragarh. The important characteristics of this species are plants

simple, leaves stiff, tufted and forming a bud like structure when dry, margin sharply toothed in

upper part of the leaves, costa ends in a sharp awn like point. Leaf base 1/4 to 1/5 of the total leaf

length, lamellae 5 6 cells high, end cells of lamellae thick walled, smooth rectangular. The present

study recognizes Pogonatum perichaetiale subsp. thomsonii a rare species from Uttarakhand

which is a new addition to west Himalayan bryoflora of India.

Keywords: Polytrichaceae - Awn like point - Lamellae - End cells - India.

[Cite as: Sahu V & Asthana AK (2014) Pogonatum perichaetiale subsp. thomsonii (Mitt.) Hyvnen - An

uncommon species from western Himalaya. Tropical Plant Research 1(3): 1315]

INTRODUCTION

Genus Pogonatum belongs to family polytrichaceae. This genus is easily recognized by its thick, rough

textured leaves and hairy calyptra. In India this genus is represented by 18 species (Gangulee 1969, Hyvnen

1989, Asthana & Sahu 2012, Sahu & Asthana 2013). Gangulee (1969) described 4 species within section

Cephalotrichum (C. Muell.) Broth. from eastern India (P. perichaetiale ( Mont.) A. Jaeger, P. thomsonii (Mitt.)

A. Jaeger, P. tortipes (Mitt.) A. Jaeger and P. muticum Broth.). Hyvnen (1989) synonmized P. thomsonii

(Mitt.) Jaeag. and P. tortipes (Mitt.) A. Jaeger under P. perichaetiale subsp. thomsonii and P. muticum into P.

neesii (Mll. Hal.) Dozy. Only two valid species were reported in the section Cephalotrichum from India at

present. P. perichaetiale subsp. thomsonii can easily be distinguished from P. perichaetiale subsp. perichaetiale

with serrated leaf margin and aristate leaves. The key characters of this taxon are: leaves aristate, margin

serrulate at top, forming a bud like structure when dry and end cells of lamellae thick walled, quadrate to short

rectangular. Chopra & Kumar (1981) described 6 species from western Himalaya and adjacent plains (P.

perichaetiale, P. thomsonii, P. himalayanum Mitt., P. microstomum (R. Br. ex Schwgr.) Brid., P. neesii, P.

urnigerum (Hedw.) P. Beauv.), out of which 4 taxa are valid. The present study has revealed Pogonatum

perichaetiale subsp. thomsonii as a new addition to Uttarakhand, west Himalayan bryoflora.


Plant specimens were collected from Watan Village, Pithoragarh district of Uttarakhand, western Himalaya,

India. Plants were air dried and transferred to brown packets. For morphological and anatomical study plant

samples were soaked and washed in tap water and were mounted on glass microslide in 30 % glycerine to

investigate under microscope. Sections were cut free hand with a razor blade. Observations were made under

Olympus compound microscope. The measurements were taken with the help of oculometer. The voucher

specimens were deposited in Bryophyte Herbarium, National Botanical Research Institute, Lucknow (LWG).

TAXONOMIC DESCRIPTION

Pogonatum Palisot de Beauvois in Mag. Enc., 5: 329 (1804).

Plants usually dioicous, stiff, robust, erect, simple. Leaves curled to crispate when dry and erectopatent when

moist. Leaves lanceolate from a sheathing bases, margin not bordered, usually serrate at upper portion and

numerous longitudinal lamellae on ventral surface. Leaf costa percurrent to excurrent. Seta long, capsule erect to

inclined, subcylindrical, stomata absent. Peristome teeth 32, sometimes 16, calyptra hairy, cucullate.

Sahu & Asthana (2014) 1(3): 13 15 .


Figure 1. Pogonatum perichaetiale subsp. thomsonii: A, Plant in dry condition; B, Plant in wet condition; C, Leaves; D,

Apical margin of Leaf; E & F, Cross sections of leaves showing Lamellae; G, Apical cells of leaf; H, median cells of leaf;

I, basal cells of leaf.

P. perichaetiale subsp. thomsonii comes under the section Cephalotrichum. The important characteristics of

this section are that plants are small, stiff, leaves tufted at top. Leaf margin dentate at apex or entire, costa

excurrent in a sharp point or ending at the tip into a long awn like point. Lamellae 4 5cells high (sometimes up

to7), end cells bigger quadrate to rectangular, thick walled, smooth and 16 Peristome teeth each having a

bifurcated axial pillar.

Pogonatum perichaetiale subsp. thomsonii (Mitt.) Hyvnen, in a synopsis of genus Pogonatum (Polytrichaceae,

Musci). Acta Bot. Fennica 138: 1 87 (1989). (Fig. 1).

Polytrichum thomsonii Mitt., J. Linn. Soc. Bot. Suppl. 1:155 (1859).

Pogonatum thomsonii (Mitt.) A. Jaeger. Ber. Thtigk. St. Gallischen Naturwiss. Ges. 1873 74: 257 (1875);

Pogonatum tortipes (Mitt.) A. Jaeger. Ber. Thtigk. St. Gallischen Naturwiss. Ges. 1873 74: 257 (1875);

Pogonatum thomsonii var. tibetanum Chen, Sci. Exped. Qomolongma Reg. 235.14 (1962).

Sahu & Asthana (2014) 1(3): 13 15 .


Plants dark brown, erect, simple, 12 15 mm long. Leaves stiff, tufted and forming a bud like structure when

dry, Lower leaves small. Leaves erectopatent, lanceolate from a wider transparent sheathing base, 4 5 mm long

and 0.96 1.12 mm wide, margin sharply toothed in upper part of the leaves. Leaf costa ends in a sharp awn like

point. Leaf base 1/4 to 1/5 of the total leaf length. In cross section of leaf, lamellae covering almost the entire

ventral leaf surface, lamellae 5 6 cells high, end cells of lamellae thick walled, smooth reddish brown,

rectangular with top cell flat or rounded. Apical cells of leaf 12 16 m long and 8 12 m wide, short quadrate.

Basal cells of leaf 20 40 m long and 12 20 m wide, quadrate to rectangular. Leaf costa 140 160 m wide at

base. Sporophyte not seen.

Specimens examined: INDIA, Western Himalaya, Uttarakhand, Pithoragarh, Near Watan Village, 27.09.1990,

V. Nath 205087A (LWG).

Habitat: ca. 3500 m, on soil.

Distribution: India (Simla, Sikkim), Bhutan, South eastern Tibet, Nepal, China.

Hyvnen (1989) synonymized Pogonatum thomsonii and P. tortipes under P. perichaetiale subsp.

thomsonii. In the case of P. tortipes end cells of lamellae are smooth, thick walled, 4 5 cells high, elongated

rectangular with top cells flat and leaf basal part 1/3 of total leaf length, basal cells rectangular up to 145m

long and 24 m wide while in P. thomsonii end cells of lamellae cup shaped with depressed top, lamellae 5 7

cells high, basal leaf cells up to 60m long and 17 m wide (Gangulee 1969). Characteristic end cells of

lamellae and basal leaf portion might be the reason for making P. perichaetiale subsp. thomsonii as separate

subspecies. In our specimens end cells of lamellae are 5 6 cells high, thick walled, smooth, elongated

rectangular, with top cells flat or rounded and basal portion of leaf 1/4 to 1/5 of the total leaf length. P. tortipes

was collected by Hooker in Japanese Expeditions in 1960 63 from Sikkim and it is known in India from that

collection only. Chopra & Kumar (1981) examined the specimen no. 6202 (BM) of P. thomsonii but in that

specimen date of collection and altitude was not mentioned. Pogonatum perichaetiale subsp. thomsonii is very

rare and it has been collected from Pithoragarh, western Himalaya after 30 years. It is still untraced despite

several collections in the area in past few decades. After Hyvnen treatment of this taxon, the plants have been

identified and described from Pithoragarh region of western Himalaya for the first time.

ACKNOWLEDGEMENTS

Authors are grateful to the Director, National Botanical Research Institute (CSIR), Lucknow for

encouragement and providing the facilities and work has been carried out under In house project OLP-0083.

REFERENCES

Asthana AK & Sahu V (2012) Two mosses new to western Himalayan Bryoflora. Phytotaxonomy 12: 6367.

Chopra RS & Kumar SS (1981) Mosses of the western Himalayas and adjacent plains. Published by The

Chronica Botanica Co., New Delhi, India, 142 p.

Gangulee HC (1969) Mosses of Eastern India and adjacent regions Vol I. Published by Author, printed at Sree

Saraswati Press, Calcutta, India, pp. 94180.

Hyvnen J (1989) A synopsis of genus Pogonatum (Polytrichaceae, Musci). Acta Botanica Fennica 138: 187.

Sahu V & Asthana AK (2013) Genus Pogonatum P. Beauv. in Singalila National Park (Darjeeling), eastern

Himalaya, India. Geophytology 43(2): 11724.

www.tropicalplantresearch.com 16 Published online: 31October 2014

ISSN (E): 2349 1183 ISSN (P): 2349 9265

1(3): 1621, 2014

Research article

Species composition and structure of Sal (Shorea robusta

Gaertn. f.) forests along disturbance gradients of Western

Assam, Northeast India

Debajit Rabha

Department of Ecology & Environmental Science, Assam University, Silchar, Assam, India

Corresponding Author: [email protected] [Accepted: 12 October 2014]

Abstract: The present paper deals with the structure and species composition of undisturbed and

disturbed secondary Sal forests of Goalpara district, Western Assam, Northeast India. Species

richness was recorded very low with only 3 species in undisturbed Sal forests compare to the 18

species in disturbed Sal forests. The density and basal area were recorded high in undisturbed

forests than the disturbed one. Shorea robusta is the single dominant species and constitute the

bulk of the stocks in both forests types. Girth class distribution of density revealed the dominance

of middle girth classes in undisturbed forests whereas in disturbed forests 45 % of the total density

recorded in lowermost girth class. Anthropogenic disturbances influence the forests structure,

functions as well as services in both forests types in the present study.

Keywords: Species diversity - Density - Disturbance index - Sal forests.

[Cite as: Rabha D (2014) Species composition and structure of Sal (Shorea robusta Gaertn. f.) forests along

distribution gradients of Western Assam, Northeast India. Tropical Plant Research 1(3): 1621]

INTRODUCTION

Sal (Shorea robusta Gaertn. f.) is one of the dominant tree species in the tropical moist as well as dry

deciduous forests in India (Champion & Seth 1968) and frequently forms a mono-specific canopy (Rautiainen &

Suoheimo 1997). Sal is well known for its high timber value and government always attempted to manage Sal

forests for commercial timber production in order to increase revenue (Gautam & Devoe 2006). Sal tree grows

gregariously and tends to form dense vegetation in its natural habitat. Natural Sal forests have high resilience

capacity and survive through regeneration (Soni 1961, Qureshi et al. 1968). In India, Sal forests are found to

occur gregariously in the northern and central regions and cover approximately 13.30% of the total forest area of

the country (Upreti & Nayaka 2005). There is almost a continuous belt of Sal stretching along the sub-

Himalayan tract from Punjab to Assam (Pandey & Shukla 2003) in the northern Indian region.

In Assam, Sal is a semi-deciduous species and found in the form of high forest and coppice forest confined

specially to the Western part of Assam (Sarma & Das 2012). Champion & Seth (1968) categorized Assams Sal

forests as Tropical Moist Deciduous Forest further divided into Khasi hill Sal forest (3C/C1 1a (ii)) and

Kamrup Sal forest (3C/C2 2d (iv)). Kamrup Sal forests are more prominent and confined in Western part of

the state.

Disturbances not only influence diversity but also regeneration and dominance of tree species (Lawes et al.

2007). Recurrent anthropogenic disturbances treated as a major threat of natural Sal forests which can change its

structure as well as function (Lalfakawma et al. 2009). Due to the ongoing over-exploitation, deforestation,

encroachment and alteration in land use and land cover the mother Sal forests gradually replace by secondary

regenerated Sal forest of the low lying areas of Assam (Deka et al. 2012). Again regeneration was very poor

where soil moisture is inadequate and which experienced higher degree of disturbances such as fire and different

human activities (Padey & Shukla 2001, Chauhan et al. 2008). Chitale & Behera (2012) stated that moisture is

one of the key factors that influence the distribution to shift the Sal forests towards northern and eastern India

due to changing climate. Ahmed & Medhi (2005) estimated that there was shrinkage of 1050.46 hectares reserve

forests and proposed reserve forest areas of Goalpara District during the period 19812002 due to encroachment

for human habitation, pasture and agricultural uses. These are causing loss of Sal forest trees at a very fast rate,

thereby encouraging the spread of mix forest communities (Sarma & Das 2012). Timely, accurate assessment

Rabha (2014) 1(3): 1621 .


and understanding of the dynamics of plant resources is important for their sustainable management, utilization

and biodiversity conservation (Sarkar & Devi 2014). Comparatively a good number of quantitative studies of

community attributes are available for tropical Sal forest of northeast India (Uma Shankar 2001, Ahmed &

Medhi 2005, Lalfakawma et al. 2009, Deka et al. 2012, Sarma & Das 2012, Dutta & Devi 2013) but in Western

part of Assam which constitute the major partion of Kamrup Sal forest (Champion & Seth 1968) have not

received much attention, except few similar studies (Deka et al. 2012, Sarma & Das 2012). Therefore the

present study deals with the species composition and other community attributes of undisturbed and disturbed

Sal forest of Goalpara District, Western Assam, Northeast India.


The study was conducted in undisturbed and disturbed Secondary Sal forest located in Goalpara District,

Western Assam, Northeast India (Fig. 1). The geographical location of Goalpara District is between latitude 25

53'26 30' N and longitude 90 07'91 05' E. The vegetation was analysed by delimiting a total of five 0.1

Figure 1. Location of the study area in Goalpara District, Western Assam, Northeast India.

hectare quadrats randomly in each undisturbed and disturbed Sal forests. The girth of all the trees ( 10 cm

GBH) within the sampling area were measured at breast height (i.e. 1.37 m above the ground) and identified.

The climate is damp and warm humid and average annual rainfall of last five-year period (20082012) was

2173.02 mm yr-1

(Hydromet Division 2013).

Quantitative analysis of tree vegetation for Density and Basal area were done by following Misra (1968).

The importance value index (IVI) is the sum of relative density, relative frequency and relative dominance.

Shannon-Wiener diversity index (Shannon & Wiener 1963) was calculated from the IVI values using the

formula -

H =

Rabha (2014) 1(3): 1621 .


Where, is the proportion of individuals of species and total number of individuals all the species

( /N).

Concentration of dominance (cd.) was measured by Simpson index (Simpson 1949).

Cd. =

Where, is same as Shannon-Wiener diversity index.

A disturbance index for each forest site was calculated following Kanzaki & Kyoji (1986), Pandey & Shukla

(2001) and Borah et al. (2014). The disturbance index (DI) was calculated as the basal area of cut trees

measured at the ground level expressed as fraction of total basal area of all trees:

DI % = Basal area of cut stumps

100 Total basal area (cut stumps basal area + Standing tree basal area)

RESULTS

Species richness of pure Sal forests is generally very poor. In the present study only 3 species belonging to

three families was recorded in undisturbed forests whereas 18 species representing 14 families in disturbed Sal

forests (Table 1). Disturbances might be responsible for arrival and establishment of new species in disturbed

Table 1. Cumulative results of the undisturbed and disturbed Sal forest of Western Assam, Northeast India.

Parameter Undisturbed Disturbed

Species number 3 18

Family number 3 14

Density (tree ha-1

) 410 306

Basal area (m2 ha

-1) 26.40 12.90

Shannon index 0.73 2.05

Simpson index 0.60 0.25

Disturbance index (DI %) 7 51

Sal forests besides its high resilience capacity. The density and basal area of the tree species were significantly

lower in the disturbed forests than the undisturbed forests. The encountered density as well as basal area was

410 tree ha-1

and 26.40 m2 ha

-1 in undisturbed and 306 tree ha

-1 and 12.90 m

2 ha

-1 in disturbed forests

respectively (Table 1). Disturbance index indicated the degree of disturbance and found high (51%) in disturbed

forests and less (7%) in undisturbed forests (Table 1). Shorea robusta was found dominant in both undisturbed

and disturbed forests based on IVI score (Table 2). IVI score of each species in both forest types are shown in

Table 2.

In each forest type distribution of density and basal area in different GBH classes was shown in figure 2. In

undisturbed forests maximum density (30%) was recorded in 7090 cm GBH class and overall 78% density in

middle girth classes (50 cm to 130 cm GBH class) evidenced the post mass regeneration of that particular forest.

In disturbed forests maximum density (45%) was recorded in lowermost i.e. 1030 cm girth class and it

drastically decrease in successive girth classes hints its past disturbance history and the resilience capacity.

Density of other species was found high in disturbed Sal forests especially in lower girth class (Table 3).

Diversity index was comparatively more in disturbed forests than undisturbed forests (Table 1).

Figure 2. Girth class distribution of tree species in Sal forest: A, undisturbed; B, disturbed.

Rabha (2014) 1(3): 1621 .


Table 2. IVI score of each species in undisturbed and disturbed Sal forests of Western Assam, Northeast India.

S.No. Species name Undisturbed Disturbed

R.De R.Fr. R.Do. IVI R.De R.Fr. R.Do. IVI

1 Aegle marmelos (L.) Corr. 1.31 4.44 0.47 6.22 - - - -

2 Alstonia scholaris (L.) R.Br. 1.31 4.44 0.09 5.84 - - - -

3 Artocarpus chama Buch.-Ham. 0.65 2.22 0.14 3.02 - - - -

4 Callicarpa arborea Roxb. 2.61 6.67 7.75 17.03 - - - -

5 Dillenia indica L. 0.65 2.22 0.21 3.08 - - - -

6 Dillenia pentagyna L. 3.92 8.89 2.17 14.98 - - - -

7 Ficus religiosa L. 0.65 2.22 3.73 6.61 - - - -

8 Holarrhena pubescens (Buch.-

Ham.) Wall. ex G.Don 0.65 2.22 0.02 2.90 - - - -

9 Litsea monopetala (Roxb.) Pers. 3.92 8.89 1.26 14.07 - - - -

10 Mallotus ferrugineus (Roxb.)

Muell. Arg 3.27 8.89 1.09 13.24 - - - -

11 Mitragyna rotundifolia (Roxb)

O. Kuntze 1.96 4.44 0.31 6.72 - - - -

12 Shorea robusta Gaertn. 62.09 11.11 71.25 144.45 94.14 41.66 90.22 226.04

13 Schima wallichii (DC) Kuntze 7.19 11.11 8.22 26.52 3.41 33.33 5.53 42.27

14 Spondius pinnata 1.96 4.44 0.31 6.72 - - - -

15 Streblus asper Lour. 1.31 2.22 0.03 3.56 - - - -

16 Sterculia villosa Roxb. 2.61 4.44 0.62 7.68 - - - -

17 Terminalia bellirica (Gatertn.)

Roxb. 2.61 6.67 2.17 11.45 2.43 25.00 4.24 31.68

18 Toona ciliata M. Roem. 1.31 4.44 0.17 5.92 - - - -

Total 100 100 100 300.00 100 100 100 300.00

*R.De.= Relative density; R.Fr.= Relative frequency; R.Do.= Relative dominance; IVI= Importance Value Index.

Table 3. Density of Sal and other species in different girth class in undisturbed and disturbed Sal forest of Western Assam,

Northeast India.

GBH Class (cm) Species Density (tree ha

-1)

Undisturbed Disturbed

10-30 Sal 40 72

Other species 8 66

30-50 Sal 8 18

Other species 2 14

50-130 Sal 322 76

Other species 12 24

>130 Sal 16 30

Other species 2 6

DISCUSSIONS AND CONCLUSION

In present study only 3 species was found in undisturbed Sal forests agreement with the study carried out by

Stainton (1972) in Pure Sal forests of Nepal. More species number (18 species) in disturbed Sal forests might be

due to the anthropogenic disturbances which favour arrival and establishment of new species. In the present

study overall species number is quite low compare to the other studies reported from different part of Northeast

India (Uma Shankar 2001, Lalfakawma et al. 2009, Deka et al. 2012, Sarma & Das 2012, Dutta & Devi 2013).

The density of undisturbed forests was found 410 tree ha-1

and it is comparable to other studies done in different

Sal forests of the country such as 294559 tree ha-1 in Central India (Jha & Singh 1990), 484 tree ha-1 in Eastern

Himalaya, Meghalaya (Uma Shankar 2001), 408 trees ha-1

in Gorakhpur, India (Padey & Shukla 2003), 438 tree

ha-1

in moist Sal forests of West Bengal, India (Kushwaha & Nandy 2012), 422 tree ha-1

in Doboka reserve

forest, Assam, NE India (Dutta & Devi 2013). Comparatively less density in disturbed forests especially >50 cm

GBH class trees (136 tree ha-1

in disturbed against 340 tree ha-1

in undisturbed forests) might be due to the

various anthropogenic disturbances (Table 2). In the present study the basal area was recorded 26.40 m2 ha

-1 in

undisturbed and 12.90 m2 ha

-1 in disturbed Sal forests. Similar basal area (729 m2 ha-1) was reported from Sal

forest of Central India (Jha & Singh 1990). High density of other species in disturbed forests might be due to the

canopy gaps resulted from the disturbances. Disturbances enabled increased light intensity and ultimately

change the environmental condition make favourable for other lights demanding successional species (such as

Rabha (2014) 1(3): 1621 .


Schima wallichii, Callicarpa arborea etc.) leading towards mix forest communities. Species richness of

disturbed forest is a cumulative outcome of differential responses of species to disturbances (Sagar et al. 2003).

Kushwaha & Nandy (2012) reported that climatic conditions-mainly the rainfall, disturbance regimes and the

management practices influenced the species composition and community structure of Sal forests while in the

present study differences occur mainly because of the disturbance regimes.

Sal is a very important tree species and usually harvested for its timber. The Sal forests of Goalpara district

of Assam were exposed to different intensities of fire and anthropogenic disturbances in the past. Sarma & Das

(2012) stated that Sal forests of Western Assam has been facing great biotic pressures such as illegal felling,

firewood collection, encroachment of peripheral areas leading to pure Sal forests to mix forests which was also

reflected in the present study. Weeds and creeper also greatly influenced the regeneration of Sal forests. The

major threats such as illegal tree felling, firewood collection, encroachment of peripheral areas might be due to

the inadequate conservation strategy, negligence of concerned forest departments. The ongoing disturbances, if

not control then these undisturbed pure Sal forests may degrade and convert to the mix forests in the very near

future.

ACKNOWLEDGEMENTS

Author is thankful to the forest department of Goalpara district for permission and support during the

fieldwork.

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www.tropicalplantresearch.com 22 Published online: 31 October 2014

ISSN (E): 2349 1183 ISSN (P): 2349 9265

1(3): 2226, 2014

Research article

Comparative evaluation of nutritional, biochemical and

enzymatic properties of the mycelium of two Pleurotus species

Ashutosh Rajoriya1, Anuradha Panda

2 and Nibha Gupta

1*

1Plant pathology and Microbiology division, Regional Plant Resource Centre, Bhubaneswar-751015, Odisha

2MITS School of Biotechnology, Bhubaneswar, Odisha

*Corresponding Author: [email protected] [Accepted: 20 October 2014]

Abstract: Aim of the present studies focuses on nutritional, antioxidant and extracellular

enzymatic activity of mycelium of Pleurotus sajor-caju and Pleurotus florida. Results shows that

both of the mushroom mycelium possess multiple nutritional, antioxidant components along with

good extracellular enzymatic activities. Methanolic extract of Pleurotus sajor-caju showed higher

phenolic and flavonoid content (1.010.57 mg gm-1

and 0.140.01 mg gm-1

) than Pleurotus florida

(0.450.05 and 0.110.01 mg gm-1

). A high alkaloid content was exhibited in P. sajor-caju than P.

florida, apart from the antioxidant components. P. sajor-caju showed high protein and

carbohydrate content i.e. 10.551.62 mg gm-1

and 32.167.16 gm 100gm-1

respectively, as

compared to P. florida which showed less amount of protein and carbohydrate content (8.50015

mg gm-1

and 8.301.09 gm 100gm-1

). Enzymatic screening showed good activity of amylase and

lipase where as Xylanase and protease activity in both the mushroom mycelium was negative.

Overall studies revealed that both the mushroom mycelium are potential source of antioxidants and

extracellular enzymes, especially flavonoids, amylase and lipase.

Keywords: Pleurotus - Mycelium - Nutritional - Antioxidants - Enzymatic.

[Cite as: Rajoriya A, Panda A & Gupta N (2014) Comparative evaluation of nutritional, biochemical and

enzymatic properties of the mycelium of two Pleurotus species. Tropical Plant Research 1(3): 2226]

INTRODUCTION

Wild edible mushroom have been integrated part of the diet, especially among rural, urban dwellers and

tribal people. Some of the common edible mushrooms, which are predominantly consumed in India are

Pleurotus sajor-caju, P. florida, P. platypus, P. djamor, Volvariella volvacea and Calocybe indica (Pan et al.

2008; Ramkumar et al. 2010). Pleurotus species is known as oyster mushrooms, which are widely spread

saprophytic macrofungi and distributed throughout the temperate and tropical forests of the world (Gunde-

Cimerman 1999). Oyster mushrooms are now in second rank among the cultivated mushrooms in the world

(Chang 1991) and are known to have potent antitumor, antimicrobial activities (Zhang et al. 1994; Gerasimenya

et al. 2002). Pleurotus sp are rich in minerals (Ca, P, Fe, K and Na) and vitamin C, B-complex (alarrmak

2007). Apart from the different nutritional and antioxidant components mushroom mycelium possess different

enzymes (Nonaka et al. 1997; Bose et al. 2007; Kadimaliev et al. 1998). Pleurotus is known for the different

cellulolytic and amylolytic enzymes (Sawiska & Kalbarczyk 2011; Jonathan & Adeoyo 2011). Recently

Pleurotus ostreatus and P. sajor-caju is characterized for the protease activity (Choi & Shin 1998; Ravikumar et

al. 2012). In Odisha mainly oyster mushroom Pleurotus sajor-caju and Pleurotus florida are grown

commercially. Both of them are liked by local people on account of unique characteristic of aroma and taste. In

the present work, this was taken into the consideration because reports suggests that fruit body of both of the

species possess good nutritional and antioxidant components along with industrially important enzymes and

since mycelium is the miniature of fruit body, therefore same behaviour was expected from the respective

mushrooms, hence it intended to evaluate the mushrooms nutraceuticals (Nutritional and Pharmaceutical)

potential.

Rajoriya et al. (2014) 1(3): 2226 .



Nutritional analysis

Protein estimation was done by the method given by Bradford (1976). Estimation of carbohydrates was

carried out by following phenol sulphuric acid method (Dubois et al. 1956; Hedge & Hofreiter 1962). Reducing

sugars in the mycelium was done by following dinitrosalicylic acid method (Miller 1972). Non reducing sugar

was calculated by following the formula of Nazarudeen (2010).

Antioxidant analysis

One gm of fresh mycelium sample was disintegrated with 10 ml of methanol. Samples were stirred for 15

minutes for effective extraction and centrifuged at 3000 rpm for 20 minutes. Supernatants were referred as

methanolic extract and kept at 4 C until analysis (Puttaraju et al. 2006). The DPPH activity was estimated in the

methanolic extracts by colorimetric method (Chan et al. 2007). Ascorbic acid equivalent Antioxidant Capacity

(AEAC) was calculated by calibrating the value of above absorbance in standard ascorbic acid curve and

expressed in mg per gram of dried sample. Ferric Reducing Antioxidant Power (FRAP) assay was done by

following the method of Benzie & Strain (1996) and Athavale et al. (2012) and. The total phenolic content in

the mycelium were determined through Folin-phenol method with slight modifications (Singleton & Rossi

1965). The flavonoid content of sample was estimated by using aluminium chloride colorimetric technique and

flavonoid content was expressed in terms of mg quercetin equivalents per gram of extract (Chang et al. 2002).

The concentration of -carotene and lycopene in mushroom mycelium extracts was estimated

spectrophotometrically (Nagata & Yamashita 1992; Barros et al. 2007). Alkaloid content in the mushroom

mycelia was quantified spectrophotometrically (Srividya & Mehrotra 2003). Tannin content was estimated in

the sample by Folin denis reagent tannic acid was served as standard and expressed in mg gm-1

(Schanderl

1970).

Extracellular enzymatic activity

i) Amylase activity: All the mushroom mycelium was screened for the extracellular amylase activity for

which starch agar media was used. After the appreciable amount of the growth in plates they were

flooded with 1% iodine solution. Clear zone around the mycelial growth was recorded for the starch

hydrolysis activity.

ii) Cellulase activity: The medium containing 0.5% sodium salt of carboxymethylcellulose was used for the

tests. After the mycelial colonization plates were flooded with congo red solution (0.2%) and washed

with 1M NaCl solution followed by the incubation period of 15 minutes.

iii) Lipase activity: Spirit blue agar media was used for the screening of lipase activity. After the requisite

amount of growth of mushroom mycelium a clear zone or precipitate was observed for the positive

organism.

iv) L-Asparaginase activity: For screening of L- Asparaginase activity, medium containing 1% L- asparagine

was used where L-asparagine served as an active ingredient, after the mycelial growth plate was flooded

with Nesslers reagent. Plates showing pink coloration after the addition were recorded as extracellular

L- asparaginase producer.

v) Protease activity: Gelatin agar media was used for the screening of protease producing organism, for

which centre inoculation was done, after the incubation of 10 days plates were flooded with the reagent

containing 15% HgCl2 and 20% HCl.

vi) Xylanase activity: Medium containing xylan was used for the screening of Xylanase activity in mushroom mycelium. After the appreciable growth in the plate it was flooded with 0.1% Congo red,

incubated for 30 minutes and washed with 1M NaCl subsequently. Plate was observed for the formation

of clear zone for the production of Xylanase enzyme.

RESULTS AND DISCUSSION

In the present studies moderate to high nutritional components and antioxidant activities with varying levels

of phenolics, proteins and alkaloids were recorded in the two species of Pleurotus (Table-1). Relatively higher

amount of the protein content (10.551.62 mg gm-1

and 8.500.15 mg gm-1

) in both of the species was observed

as compared to the other species of Pleurotus as reported by Jean-Phillip (2005). Carbohydrate content in the

Pleurotus sajor-caju and Pleurotus florida was 32.16 and 8.30 gm 100gm-1

, respectively which was less than

the cultivated variety of Pleurotus as reported by Paz et al. (2012) but much more than the reports of Boda et

al. (2012). Pleurotus along with many other types of edible mushrooms have been known as a potent source of

Rajoriya et al. (2014) 1(3): 2226 .


nutrients as well as natural antioxidants. Findings from this research showed that fungal mycelia studied have

antioxidant capacity where FRAP and DPPH free radical scavenging activities assay showed a remarkable

difference between both the species. P. sajor-caju showed higher DPPH scavenging activities than P. florida i.e.

Table 1. Nutritional components and antioxidant activities of Pleurotus spp.

S. No. Parameters P. sajor-caju P. florida

1 Protein (mg/gm) 10.551.62 8.500.15

2 Carbohydrates (gm/100gm) 32.167.16 8.301.09

3 Red. Sugars (mg/gm) 24.371.04 12.911.51

4 Non Red. Sugars(gm/100gm) 29.727.09 7.001.02

5 DPPH scavenging (%) 45.530.01 9.95 1.14

6 AEAC(mg/gm) 0.101.69 0.020.00

7 FRAP (mg AEAC/gm) 0.790.10 0.060.01

8 Phenolics (mg/gm) 1.010.57 0.45 0.05

9 Flavonoids (mg/gm) 0.140.01 0.11 0.01

10 Beta carotene (mg/gm) 0.0380.012 0.0180.005

11 Lycopene (mg/gm) 0.0160.001 0.0070.002

12 Tannins (mg/gm) 5.180.64 4.480.86

13 Alkaloids (mg/gm) 0.490.01 0.470.08 DPPH- 2, 2-Diphenyl-1-picryl hydrazyl

AEAC- Ascorbic acid Equivalent Antioxidant Capacity.

FRAP- Ferric Reducing Antioxidant Power

(45.530.01%) and (9.95 1.14%) along with their corresponding AEAC value which was 0.101.69 mg gm-1

and 0.020.00 mg gm-1

, respectively. Phenolic and flavonoid content in both of the species confirms the study

of Vamanu (2012) and Jeena et al. (2014) in P. ostreatus. High amount of - carotene (0.0380.012 mg gm-1)

and lycopene (0.0180.005 mg gm-1

) content was recorded in P. sajor-caju where as comparatively less amount

of the same was recorded in P. florida. Presence of -carotene and lycopene was less as compared to the

investigations of Pal et al. (2010). Alkaloids are responsible for different cytotoxic and antimicrobial properties

(Ozcelik et al. 2011) Present study revealed the high amount of alkaloid was recorded in P. sajor-caju

(0.490.01 mg gm-1

) and P. florida (0.470.08 mg gm-1

). Tannins are responsible for different biological

activities such as antioxidant, antimicrobial and antitumor activities (Yoshizawa et al. 1987; Yoshida et al.

1989; Yoshida et al. 2009). Tannin content in P. florida and P. sajor-caju ranged from 4.48-5.18 mg gm-1

.

Comparatively P. sajorcaju, exhibited better scavenging of free radicals including high levels of protein,

carbohydrate, reducing sugars, phenol along with both FRAP and DPPH scavenging activities than P. florida. In

the present studies of the enzymatic activity of these mushroom mycelium, P. florida showed higher amylase

and lipase activity than P. sajor-caju, both the species were negative for the Xylanase and prote

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Volume 1, Issue 3 of Tropical Plant Research