N.Ya. Kyyak, O.L. Baik
Institute of Ecology of the Carpathians, NAS of
Ukraine
11, Stefanyk St., Lviv 79000, Ukraine
e-mail:
kyyak_n@i.ua
PHOTOSYNTHETIC ACTIVITY OF THE MOSSES ON THE DEVASTATED TERRITORIES OF
SULPHUR EXTRACTION
INTRODUCTION
Functioning of photosynthetic plants apparatus
determines productivity of plant cover under changeable conditions of natural
environment. Information on functioning of photosynthetic apparatus and bryophytes productivity will give us possibility to
estimate their role in preserving biovariability and contribution to the total
productivity of plant cover. Now there are a considerable number of monographs,
devoted mainly to biology, systematization, anatomy, morphology and physiology
of mosses rather briefly [2; 3; 7].
Productivity and peculiarities of moss biology were investigated in detail,
taking Sphagnopsida, bryophytes of wood groups and bogs, tundra ecosystems,
chalky meadows of Europe as examples [4; 9]. The investigation of bryophyte role in populating and restoration of
technogenically devastated territories has not been practically investigated.
In this aspect the unique object for investigation is represented by devastated
territories of Javoriv state mining-chemical enterprise (SMCE) „Sirka” (Ukraine, Lviv
region), where simultaneously
with mechanical and chemical destruction of natural ecosystems in the process
of sulphur extraction by open-pit method, the rocks which essentially differ
from the initial substrate by their chemical and physical properties are taken
out on the surface and are stored in dumps [5]. Besides, the dump slopes of different age and
consisting of various rocks are destroyed by erosion processes complicating
plants fixation and the formation of plant cover. Bryophytes are the first to
populate on the dump substrates gradually forming dense, multispecific
coverings. The important mosses role as pioneer plants in plants communities is well-known [4; 8]. Gradually dying off the pioneer bryophyte species
prepares substrate for other mosses and vascular plants population. Mosses form
thick cover with high biomass and projective covering indices on devastated
territories after sulphur extraction.
It is known that carbon
accumulation is determined by phytocenose ability to absorb CO2 in
the process of photosynthesis and to some extend depends on the chlorophyll
content in plants. Therefore, the study of the plastid pigments content
properties, mosses photosynthesis intensity on the dump No 1 of SMCE „Sirka”
territory will give opportunity to establish their role in the productive
process of plant cover and on the technogenic substrates of sulphur production.
MATERIALS
AND METHODS
The object of
investigation was bryophytes from the dump No 1 of Yazivsky sulphur deposit (Ukraine, L’viv region, Yavoriv district). 4 moss
species, which are dominants and subdominants under these conditions: Barbula
unguiculata Hedw., Bryum
argenteum L. and Bryum caespiticium Hedw.
and Brachytecium salebrosum (Hoffm. ex F. Weber & D. Mohr) Schimp. have
been chosen for investigation of photosynthesis processes. Moss species have
been collected on 7 investigated transects (the dump crest and in three
transects on the north and south slopes – base, slope, top) during 2012 year for this analysis. The content of photosynthetic
pigments has been determined in freshly collected vegetable material.
Moisture
content in moss turfs was determined by weight method and was calculated in
percentage from the weight of the absolute dry substance [6].
Chlorophyll
content and that of carotenoids was determined in 80% acetone using Arnone
method [1]. The pigments content was expressed in mg/g
of dry substance mass.
The supply of
the surface phytomass was determined by the method of registration plots having
the size 0,25 x 0,25 m [6]. The surface phytomass was sorted out according to
plant species, separating the living parts from the dead ones, it was weighed
and expressed in gr/m2. To
determine the chlorophyll index (XI) the values of chlorophyll content a and b,
and phytomass data of all groups components have been used [9]. They have been determined according to
formula: XI = (chl. a +chl. b) x phytomass and expressed in gr/m2.
RESULTS
In our
investigations chlorophylls content (a
+ b) in the leaves of investigated
moss species was in the range of 0,4–1,8 mg/g of the dry substance mass, while the
carotenoids content was from 0,2 to 1,2 mg/g of the dry substance mass. The largest
quantity of chlorophylls (1,2–1,8 mg/g of the dry substance mass) and carotenoids
(0,4–0,8 mg/g of the dry substance mass) was
determined for the species Bryum
caespiticium and Bryum argenteum
(Table 1). Perhaps, it is connected with specific
character of the life forms Bryum
caespiticium and Bryum argenteum
as they form short dense or loose turf, which keep water well. The maximum
indices of chlorophylls content in Bryum
caespiticium can be caused by rather high water content in leaves (60–70 %) compared to other investigated species. It has been established that the content of photosynthetic
pigments in moss shoots depends on exposition and locality of plants on the
slope. The maximum number of chlorophylls was found in the samples of the north
slope, that is caused by better conditions of the plants water supply in this
part of the dump.
Mosses location on the slope also
essentially influenced the content of photosynthetic pigments. The tendency to
the decrease of chlorophylls and carotenoids quantity in Bryum caespiticium and Bryum
argenteum from the dump base to the top has been observed. This is typical
of moss species both from the north and south slopes. Thus, for example, the
decrease of chlorophylls content by 30 % compared to the plants in the dump
base has been fixed for the samples of Bryum
caespiticium species collected on the dump top. That is the tension of
ecological factors, in particular, high insolation (9,0–10,0 thousand lux) and the decrease of substrate
moisture to 4,2–8,5 %, that is
characteristic of the dump top, essentially influenced the photosynthetic pigments
content. Somewhat lower level of green pigments
compared to 2 previous species (0,6–1,1
mg/g of raw material mass) has been established for Barbula unguiculata. This species often occurs on open localities
with high light intensity, that considerably changes the qualitative
composition of its pigments, as the decrease of the relative part of green
pigments and the increase of carotenoids content (0,5–1,2 mg/g of raw material mass) has been established.
Table 1.
Content of photosynthetic
pigments (mg/g of the dry substance mass) in the moss shoots on the territory
of dump No 1 (April –May 2011)
|
Locality
of moss samples collection |
chl. à |
chl. b |
a+b |
carotenoids |
chl/car |
à/b |
|
NORTH SLOPE |
||||||
|
Bryum caespiticium |
||||||
|
crest of the dump |
0,98±0,08 |
0,52±0,05 |
1,50±0,09 |
0,46±0,03 |
3,2 |
1,9 |
|
base |
0,96±0,06 |
0,62±0,03 |
1,58±0,10 |
0,41±0,02 |
3,8 |
1,6 |
|
slope |
0,90±0,09 |
0,56±0,09 |
1,46±0,09 |
0,76±0,03 |
1,9 |
1,6 |
|
top |
0,68±0,08 |
0,52±0,06 |
1,20±0,08 |
0,31±0,01 |
3,9 |
1,3 |
|
Bryum argenteum |
||||||
|
crest of the dump |
0,70±0,06 |
0,52±0,04 |
1,22±0,09 |
0,58±0,05 |
2,1 |
1,3 |
|
base |
0,68±0,03 |
0,53±0,02 |
1,21±0,09 |
0,52±0,02 |
2,3 |
1,3 |
|
slope |
0,62±0,01 |
0,53±0,02 |
1,15±0,08 |
0,42±0,03 |
2,7 |
1,2 |
|
top |
0,24±0,01 |
0,16±0,01 |
0,40±0,02 |
0,21±0,01 |
1,91 |
1,5 |
|
Barbula unguiculata |
||||||
|
crest of the dump |
0,65±0,06 |
0,43±0,03 |
1,08±0,09 |
1,18±0,05 |
0,9 |
1,5 |
|
base |
0,64±0,03 |
0,41±0,02 |
1,05±0,09 |
1,21±0,01 |
0,8 |
1,5 |
|
slope |
0,59±0,02 |
0,40±0,01 |
0,99±0,03 |
1,12±0,03 |
0,9 |
1,5 |
|
top |
0,39±0,01 |
0,24±0,02 |
0,63±0,02 |
0,73±0,01 |
0,8 |
1,6 |
|
Brachythecium salebrosum |
||||||
|
base |
– |
– |
– |
– |
– |
– |
|
slope |
0,51±0,05 |
0,64±0,02 |
1,15±0,02 |
0,28±0,03 |
4,1 |
0,8 |
|
top |
0,33±0,03 |
0,30±0,01 |
0,63±0,09 |
0,22±0,02 |
2,9 |
1,1 |
|
SOUTH
SLOPE |
||||||
|
Bryum caespiticium |
||||||
|
base |
0,69±0,03 |
0,54±0,03 |
1,23±0,09 |
0,43±0,03 |
2,9 |
1,3 |
|
slope |
1,08±0,09 |
0,68±0,04 |
1,76±0,07 |
0,51±0,03 |
3,4 |
1,6 |
|
top |
0,69±0,05 |
0,45±0,02 |
1,14±0,09 |
0,44±0,02 |
2,6 |
1,6 |
|
Bryum argenteum |
||||||
|
base |
0,91±0,09 |
0,58±0,03 |
1,49±0,11 |
0,63±0,05 |
2,3 |
1,9 |
|
slope |
0,78±0,05 |
0,45±0,02 |
1,23±0,09 |
0,38±0,01 |
3,2 |
1,8 |
|
top |
0,61±0,03 |
0,34±0,02 |
0,95±0,07 |
0,36±0,02 |
2,6 |
1,8 |
|
Barbula unguiculata |
||||||
|
base |
0,63±0,02 |
0,36±0,01 |
0,99±0,04 |
0,75±0,03 |
1,3 |
1,6 |
|
slope |
0,58±0,03 |
0,42±0,03 |
1,03±0,08 |
0,59±0,05 |
1,6 |
1,3 |
|
top |
0,47±0,01 |
0,27±0,01 |
0,74±0,03 |
0,52±0,02 |
1,4 |
1,7 |
|
Brachythecium salebrosum |
||||||
|
base |
0,51±0,03 |
0,50±0,04 |
1,1±0,09 |
0,21±0,01 |
5,3 |
1,0 |
|
slope |
– |
– |
– |
– |
– |
– |
|
top |
0,38±0,02 |
0,32±0,02 |
0,70±0,03 |
0,20±0,01 |
3,5 |
1,1 |
The correlation of chlorophylls to
carotenoids quantity (chl/c) in Barbula unguiculata amounts to 0,8–1,6. For Bryum
argenteum and Bryum caespiticium
this index is higher and is situated in the range of 2,0–4,0. In Brachythecium
salebrosum the correlation of chlorophylls to carotenoids is the highest
among all investigated moss species and reaches 5,3, that is characteristic of
the plants from shaded localities.
The smallest number of
photosynthetic pigments has been found in Brachythecium
salebrosum (0,6–1,1 mg/g of raw material
mass of chlorophylls and 0,2–0,3
mg/g of raw material mass of carotenoids). The decrease of the pigments number
by almost 30 % in the samples from the
top compared to the samples from the dump base has been also observed for this
species. Essential qualitative changes in the composition of green pigments
have been found in this species together with quantitative differences. Brachythecium salebrosum grows in shaded
places on the dump territory so adaptation to low light intensity in plants
occurs as the result of chlorophyll b
part increase in the total chlorophylls sum of assimilating
organs. In general, the chlorophylls a/b
correlation in the pigment leaves complex of all investigated species is rather
low (1,0–1,8) that is close to the plant indices of
shady type [10]. A part of
chlorophyll a in the total number of
green pigments amounts to 58–65 %, on the average, and only in the samples Brachythecium salebrosum this index
decreases to 50 % at the expense of the
increase of chlorophyll b quantity.
This testifies to the wide rate of moss reaction to the change of light
intensity, that gives them possibility to use low light intensity effectively.
Primary
productivity of moss cover. The
basis of the plants production process is the energy transformation and the
formation of organic substances in the photosynthesis process. In this
connection bryophyte contribution in the primary productivity of plant cover on
the territory of sulphur production has been estimated. Chlorophyll index (XI),
which serves as universal parameter for comparing plant components of various
morphology and systematic position, has been used as the production index. The
values of chlorophylls content a and b and phytomass data of all group
components have been used for its determination. Chlorophyll index was
determined for moss group on the dump crest with moss Bryum caespiticium, a part of which amounted to 52 % from all
phytomass. The specific plants composition is represented by 5 species
including 3 species of mosses (Barbula
unguiculata, Bryum argenteum, Bryum caespiticium) and 2 species of vascular
plants (Calamagrostis epigeios (L.)
Roth and Cirsium arvense (L.). The
structure of the surface phytomass is represented mainly by assimilating organs
and amounts to ~ 506,4 g/m2, among which a part of bryophytes constitutes 97 % (Table 2).
Table. 2.
Chlorophyll
index of plant cover on the crest of the dump (May 2012)
|
Plant species |
Chlorophyll content (à+b), mg/g of the dry substance mass |
Supply of the surface
phytomass, g/m2 |
Chlorophyll index, g/m2 |
|
|
Vascular plants |
||||
|
Calamagrostis epigeios (L.)
Roth. |
0,782±0,051 |
12,2± 1,1 |
0,0095±0,0001 |
|
|
Cirsium arvense (L.) |
0,965±0,081 |
1,7±0,09 |
0,0016±0,0002 |
|
|
Vascular plants – sum total |
|
13,9 |
0,011±0,0002 |
|
|
Mosses |
||||
|
Bryum
caespiticium Hedw. |
1,231±0,092 |
253,8±21,1 |
0,3681±0,0211 |
|
|
Bryum argenteum L. |
1,053±0,097 |
56,3±3,1 |
0,0593±0,0034 |
|
|
Barbula
unguiculata Hedw. |
0,743±0,056 |
182,5±16,4 |
0,1356±0,0092 |
|
|
Mosses – sum total |
|
492,5 |
0,563±0,005 |
|
|
Total |
506,4 |
0,574 |
||
It has been
found out, that the store of the surface phytomass is essentially larger in
dense turf mosses species (Bryum
caespiticium and Bryum argenteum)
at the expense of the number of pieces per area unit. It has been established,
that the value of chlorophyll index of moss cover on the dump crest is rather
high and amounts to 0,563 g/m2, that is caused by the essential mass
of assimilating mass organs and high content of green pigments. This index is fully comparable with the values XI,
determined for plants groups with vascular plants domination (for example, for
shrubbery group XI it amounts to 0,5-0,6 g/m2) [10]. The
obtained results show the important bryophyte role in the production processes
on technogenic territories of sulphur production.
Thus,
ecological and physiological estimation of dominant moss species on the dump
territory of sulphur extraction of mining-chemical enterprise “Sirka” tells
about the important role of these plants in the process of restoration of
sulphur deposits technogenic landscapes and the necessity to continue
investigations of peculiarities of plants communities functioning with
bryophytes domination.
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