ARTICLES
Chinese Science Bulletin 2006 Vol. 51 No. 9 1123—1129
DOI: 10.1007/s11434-006-1123-3
Physiological response of
Tamarix ramosissima under
water stress along the lower
reaches of Tarim River
ZHUANG Li & CHEN Yaning
Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
Correspondence should be addressed to Chen Yaning (email:chenyn@
ms.xjb.ac.cn)
Received October 23, 2005, accepted January 9, 2006
Abstract Tamarix ramosissima is one of the constructive species growing on both sides of Tarim
River which is favorable to constituting a natural barrier containing local deserts and protecting the oasis.
By analyzing characteristics of the main physiological
indexes, such as chlorophyll, soluble sugar, proline
(Pro), malondialdehyde (MDA), superoxide dismutase (SOD), peroxidase (POD), indole-3-acetic acid
(IAA), C3-gibberellins (GA3) and abscisic acid (ABA),
at different sections with different water tables in the
lower reaches of Tarim River, it has been found that
these physiological indexes have close correlations
with water tables. In addition, the rational ecological,
coercing and critical water tables of T. ramosissima
are 2－4 m, 6 m and 10 m, respectively, which provides an important theoretical basis for the ecological
conservation of extremely arid regions.
Keywords: Tamarix ramosissima, physiological index, water table,
Tarim River.
Tarim River within the boundaries of Xinjiang is the
longest inland river in China and its overall length is
2300 km (the main stream is 1321 km). Because of the
increasing population in the region and large-scale exploitation of water and soil resources in the upper and
middle reaches of Tarim River for the last 50 years, 320
km river course in the lower reaches of Tarim Basin has
broken since 1970s, which results in the natural desert
vegetation degenerating sharply and the land desertification aggravating. The lower reaches of Tarim River
has become one of the regions in western China where
ecological and environmental conditions are deadly
serious, which has caused great attention of the society
and the government at all levels[1].
www.scichina.com
www.springerlink.com
Tamarix, distributed widely in arid areas in the
northwest of China and growing under extremely adverse environmental conditions, such as aridity, salinization of soil, windy and dusty abominable environment, has attracted the attention of scholars by its remarkable ecological and economic benefits and unique
ecological adaptability, but the researches of domestic
and international scholars are mostly concentrated on
－
its systematic taxonomy[2 8], pharmacology composi－
－
tion[9 11] and morphologic-anatomical structure[12 15],
etc., with relatively less researches on its adversity resistance[16,17]. Researches on physiological characteristics of Tamarix under different water tables in the lower
reaches of Tarim River have not been reported. Additionally, Tamarix moving to non-bank area naturally has
been found, so that Tamarix may regenerate naturally in
desert area lacking flood irrigation is worth studying
especially.
The study of T. ramosissima ——one of the main constructive species in Tarim River basin in this text, with
a view of revealing its drought-resistant mechanism and
exploring the rational, coercing and critical water table
by analyzing the main physiological indexes at
different sections combined with water inputting
project, will provide theoretical foundation for the
expansion of Tamarix association and the conservation
of Tarim Basin.
1
1.1
Survey of research area and methods
Survey of research area
The overall length of the lower reaches of Tarim
River from Qiala to Taitema Lake is 428 km, which is
located between Taklamakan Desert and Kuluke Desert.
It possessed the good reputation of “green corridor” in
the past because of the well-growing vegetation on both
sides. It belongs to continental warm temperature zone,
fatally dry and desert weather with little precipitation,
violent evaporation, big difference in temperature, long
time sunshine and abundant light resources, and rather
dry, much sandstorm and floating dust weather. Its type
of landform is a composite mode such as crescentshaped dune range, longitudinal sand ribbon and brushy
sand, whose ground is mainly made up of fine-grained
sand soil. From south to east, the river wriggles its way
through the narrow alluvial plain between Taklanakan
Desert and Kuluke Desert, and the river bed deforms
seriously due to violent wind-erosion and wind-deposition caused by windy and dusty. In the past 30 years,
1123
ARTICLES
30 years, the river course broke and the water level descended greatly because of unreasonable exploitation of
water resources. As a result, the ecosystem was damaged seriously, with a large area of Populus euphratica
forest dying and most of shrubs and herbs becoming
into a fading state.
1.2
Materials and methods
(i) Sample collection. The samples were collected
at Yahepu, Alagan and Kaogan sections, which were
located at the upper, middle and lower sectors of lower
reaches of Tarim River respectively (Fig. 1)[1]. The sites
of sample collection were selected at the places being
100 m, 200 m, 300 m, 400 m and 500 m away from the
river bank sequentially according to the positions of
groundwater observation wells, in order to analyze the
physiological metabolism of T. ramosissima on the
grounds of water table and soil salt.
The samples of every site were composed of stochastic leaves of several plants which were chosen at
random. The size of shrubs would be as similar as possible to ensure drawing a parallel between plants with
the same age or growing time.
Fig. 1.
2
Results and analyses
2.1 The relationship between chlorophyll content of T.
ramosissima and water table
At Yahepu section, which is at the upper sector of
lower reaches where the water level is lower, the chlorophyll contents of T. ramosissima increased gradually
from the minimum of 50.10 μg/g to the maximum of
76.85 μg/g (Fig. 2). The increasing process indicated
that the water level within 500 m from the river bank
was suitable for the normal growth of T. ramosissima
The distribution of the sections in the lower reaches of Tarim River.
Table 1
The determined contents and methods of physiological indexes
Number
1124
The place and plant should remain the same for the
two experiments. The first time was July 20, 2003 (before water inputting) and the second was September 30,
2003 (in the middle period of water inputting). Water
table and water quality were determined at the same
time. Both the physiological indexes and water tables
took the average of experimental data twice.
(ii) Sample analysis measurements. Specifically
determined contents and methods are shown in Table 1,
and the physiological indexes of T. ramosissima in Table 2.
Method
1
Chlorophyll content
Zhao Shijie’s method[19]
2
Soluble sugar content
KNAUER semimicroosmometer[20]
3
Pro content
Zhu Guanglian’s method[21]
4
Water potential content
Osmometer[22]
5
MDA activity
Yang Shushen’s method[23]
6
SOD activity
Yang Shushen’s method[23]
7
POD activity
Yang Shushen’s method[23]
8
IAA content
HPLC[24]
9
GA3 content
HPLC[24]
10
ABA content
HPLC[24]
Chinese Science Bulletin
Vol. 51 No. 9 May 2006
ARTICLES
Table 2 Physiological indexes of different distances at three sections a)
Section
Alagan
Kaogan
Pro
(μg/g)
SOD
(unit/g)
POD
(unit/g)
IAA
(ng/gFW)
GA3
(ng/gFW)
ABA
(ng/gFW)
22.48
0.26
1.01
137.88
68.28
7.86
200 m
51.45
183.31
25.65
4.27
0.36
0.94
119.67
115.90
12.89
300 m
66.80
189.73
31.76
10.50
0.44
0.77
60.12
86.48
14.98
400 m
70.70
160.83
38.92
10.83
0.48
0.84
45.89
94.03
18.23
500 m
76.85
170.18
27.65
14.29
0.56
0.74
35.68
97.49
29.10
100 m
58.95
113.73
4.57
6.83
0.29
0.99
123.86
86.28
8.19
200 m
59.05
139.49
10.58
8.46
0.33
0.91
57.49
82.42
16.41
300 m
56.25
226.69
10.60
8.96
0.37
0.80
53.08
82.03
22.35
400 m
58.80
167.84
5.14
11.41
0.42
0.96
45.10
66.33
23.40
500 m
47.35
161.89
7.11
16.81
0.50
0.81
44.09
65.81
32.07
100 m
39.30
167.32
53.37
10.99
0.47
0.39
22.17
17.05
27.29
200 m
53.70
169.37
29.79
12.08
0.43
0.54
35.13
22.59
27.65
300 m
50.80
215.18
148.90
14.62
0.73
0.34
17.39
6.24
34.12
400 m
53.95
153.07
94.06
16.22
0.69
0.55
23.55
24.69
29.56
500 m
41.20
206.17
168.20
20.25
0.80
0.35
10.47
2.05
38.09
100 m
Yahepu
Chlorophyll Soluble sugar
(%)
(μg/g)
50.10
121.65
MDA
(μg/g)
3.57
Site
a) All the indexes refer to the average values.
Alagan and Kaogan sections which were located at the
middle and lower sectors of lower reaches respectively,
where water level was higher, a decreasing tendency of
chlorophyll content was shown along with the increase
of water level (Fig. 2). Among them, chlorophyll content had decreased at near 6 m water level and fell off
sharply at about 10 m at Alagan section, which resembled the change of Kaogan section at 10.11－10.32 m
water table.
Chlorophyll content is an important physiological
index that reflects the intensity of plant photosynthesis,
so the normal physiological state of a plant will be destroyed when it is injured by environmental factors,
which will be reflected by the declining degree of
chlorophyll content[25], so it can be inferred from the
above that T. ramosissima will receive aggravate coercion when the water level exceeds 6 m; when the water
level is higher than 10 m, T. ramosissima will be coerced extremely and in a critical state of death.
2.2 The relationship between soluble sugar and Pro
content of T. ramosissima and water table
Fig. 2. The relationship between chlorophyll of Tamarix ramosissima
and water table.
on the whole, which might also be associated with an
overabundance and long-time sunshine there recouping
the influence of water level on its photosynthesis. At
www.scichina.com
www.springerlink.com
Soluble sugar contents of T. ramosissima at different
sections all presented the same changing laws, namely
falling after rising during the constant dropping of water table (Fig. 3), in which, there was a slight difference
between Yahepu section and Alagan section within 100
－300 m from the river bank: the increasing degrees
were 50.79%－3.51% and 22.65%－62.52% respec1125
ARTICLES
tively, leading to lifting curves. Soluble sugar of
Kaogan section resembled that of Alagan section except a big fluctuation far from the river bank. Pro contents of Yahepu and Alagan sections changed less, and
by contrast, there was a remarkable change at Kaogan
section: both increasing and decreasing spans between
every two sectors are all obvious, presenting obvious
“w” shape as well as two sharply rising points at 9.54－
9.97 m and 10.11－10.32 m water levels separately,
with the increasing degree of the latter (372.19 μg/g/m)
far greater than the former (277.07 μg/g/m). Plants
always reduce water potential by accumulating free
proline and soluble sugar to improve their drought-resistant ability in adversity[26], which indicates that the
critical water level leading T. ramosissima to death may
be 10 m or so.
lower than those at 4.42－5.78 m and 6.46－6.79 m of
water level (4.59 μg/g/m and 5.09 μg/g/m), which
demonstrated that when the water level was about 4 m,
the growth of T. ramosissima began to be suppressed
promptly, around 6 m (6.46－6.79 m) water table
would cause serious coercion to it. The phenomenon
that MDA contents of Alagan and Kaogan sections increased in a moderate but steady manner at 100－400
m apart from the river bank but rose appreciably at 400
－500 m (about 10 m water level) indicated that T.
ramosissima had suffered severe coercion and was in a
critical state. In addition, the reason why MDA content
of Kaogan section was the highest and that of Alagan
section was higher than Yahepu section in the same
distance from the river bank, namely, the nearer to the
lower sector, the higher the MDA content was, was that
Yahepu section was in the upper reaches of waterinputting river where water condition was good, so T.
ramosissima was injured slightly. It indicated that water condition would get worse along with the dropping
of water level which resulted in water loss of T. ramosissima leaves, so MDA became greater gradually and
T. ramosissima was damaged more and more seriously.
Fig. 3. The relationship between soluble sugar, Pro contents of Tamarix
ramosissima and water table.
2.3 The relationship between MDA, SOD and POD
activities of T. ramosissima and water table
MDA increased constantly with the gradually rising
of water level (Fig. 4): the increasing degrees of SOD
at 3.12－4.42 m and 5.78－6.46 m of water level were
1126
Fig. 4. The relationship between MDA, SOD and POD activities of
Tamarix ramosissima and water table.
Chinese Science Bulletin
Vol. 51 No. 9 May 2006
ARTICLES
The rules of SOD content change at three sections
were substantially the same: all alignment increasing
with the constant decline of water table and getting up
by 0.08 unit/g/m, 0.04 unit/g/m and 0.22 unit/g/m respectively. SOD content increase was just a physiological response of T. ramosissima to adversity: under
water stress, SOD activities of drought enduring plants
would go up to inhibit the member lipid peroxidization
so as to prevent the membrane from injuring[27]. On the
contrary, POD contents of three sections decreased resembling straight lines with the gradual decline of water table, and those of Yahepu section were cut down
more greatly than those of Alagan and Kaogan sections.
There may be two reasons resulting in the dropping of
POD activities: water stress causing POD controlling
system in T. ramosissima cell to respond slowly or
synthetic ability of protein to fall. MDA contents of
three sections increased obviously, and SOD contents
rose slightly, however, POD showed a tendency to reduce, maybe because the violent peroxidization exceeds
the oxidation-resistant ability of POD and oxidation
stress is caused, thus damaging cell membrane.
to adversity, more important is its cross-adjusted traits,
so it is often used as one of the indexes to weigh plant
adversity-resistance. At Yahepu section, ABA content
ascends dramatically within 400－500 m from the river
bank where the water table is about 6 m, which assembles that of Alagan section. There were two obviously
increasing points at 9.54－9.97 m and 10.11－10.32 m
of water table at Kaogan section where ABA increasing
degrees were 23.40% and 28.82% respectively. It was
inferred from the analyses of ABA content change of
three sections that when water table was near 4 m, T.
ramosissima began to suffer coercion, and coercion
aggravating when water table was 6 m or so, and 9-10
m would endanger its existence.
2.4 The relationship between plant growth regulator
and water table
IAA, GA3 and ABA are endogenous hormones of
plants, with their contents especially proportion in plant
always influencing the development of plants during
different growth periods or under different environmental conditions.
It could be found out by surveying the datum relation curve (Fig. 5) of T. ramosissima and water table
that IAA contents of three sections all decreased with
the constant increase of water table, of which, IAA
content of Kaogan section is very fluid, rising or dropping sharply. GA3 content increased steeply to the
maximum of 115.90 ng/gFW before decreasing rapidly
to 86.48 ng/gFW and then rose gradually to 97.49
ng/gFW, showing mainly a growing tendency, however,
GA3 contents of Alagan and Kaogan sections presented
a trend of declining, the relation curve of the former
was comparatively easy and the latter fluctuated greatly.
Transversally, ABA contents of three sections went up
gradually with the increase of the distance from the
river bank, i.e. the falling of water table. Longitudinally,
within the same distance from the river bank, the nearer
to the lower reaches the higher the ABA content. ABA
is always termed “emergency hormone”, one of the
reasons is that ABA responses rapidly and significantly
www.scichina.com
www.springerlink.com
Fig. 5. The relationship between IAA, GA3 and ABA of Tamarix ramosissima and water table.
3
Discussion
(1) Various physiological indexes of T. ramosissima
have a close correlation with water table, which can
also be seen from the correlation analyses of physiological indexes and water table (Table 3), of which
soluble sugar, Pro, SOD and ABA present positive
1127
ARTICLES
Table 3 Correlation coefficient between physiological indexes of Tamarix ramosissima and water table
Water table
chlorophyll
Soluble sugar
Pro
MDA
SOD
POD
IAA
GA3
ABA
−0.3208
0.4156
0.3399
0.7464b)
0.5531a)
−0.5518a)
−0.8085b)
−0.6093a)
0.8031b)
a) Significance at P ＜0.05; b) significance at P ＜0.01.
correlation with water table but chlorophyll, POD and
IAA present negative correlation with it. In the lower
reaches of Tarim River, water stress is the most immediate and the most important factor to restrict the development of plants. T. ramosissima will make corresponding physiological response to drought-resistance
in order to diminish damage to minimum degree. In
addition, all kinds of physiological metabolisms are
characterized by a synergistic effect, which is in favor
of withstanding water stress, thus keeping the normal
survival of plants.
(2) The relationship between physiological indexes
of T. ramosissima and water table at different distances
from the river bank at three sections showed that the
changes of physiological indexes at Alagan and Kaogan
sections were not only regular but also similar. However, many changes of Kaogan section did not conform
to the theoretical laws, the relation curve swelling and
subsiding. It may be because Kaogan section was located at the coccyx of the lower reaches of Tarim River
and got less water in the course of intermittent water
inputting, which influenced the water table and soil
water not apparently, so physiological indexes there
changed irregularly.
(3) A preliminary conclusion can be inferred from
the testing of physiological indexes such as chlorophyll,
soluble sugar, MDA, Pro and ABA, combined with the
comprehensive comparison and analyses of sample investigation. In the lower reaches of Tarim River, the
rational ecological water table suitable for T. ramosissima’s survival is 2－4 m, water table over 6 m coerces
its growth seriously, and 10 m is the critical water table
which will endanger T. ramosissima’s life. The results
offer scientific basis for determining reasonable or the
least amount of water which maintains the ecological
safety of Tarim River during the water inputting.
(4) The special living condition that the lower
reaches of Tarim River has broken for nearly 30 years
moulds some special living manners of natural vegetation in the area. Wind - dispersed T. ramosissima seeds
will germ rapidly as soon as there is a flooding irrigation and the underground part grows faster than aboveground part, as a result, the roots are long enough to
1128
draw groundwater after some flooding, so whether T.
ramosissima will survive depends on groundwater
when flood diverts and there is no aboveground water
supplying any longer. The water table near the river
bank has jacked up obviously since water inputting
project was carried into execution in 2000[28], which
saves the natural vegetation growing under the special
conditions of Tarim River effectively and plays an important role in advancing the growth of natural vegetation based on T. ramosissima and P. euphratica near
both sides of the river bank.
Acknowledgements This work was supported by the National Basic Research Program of China (Grant No. 2004CB720201), the Knowledge Innovation Project of the Chinese
Academy of Sciences and the National Natural Science
Foundation of China (Grant Nos. 90502004 & 30500081).
References
1 Chen Y N, Zhang X L, Zhu X M, et al. The ecosystem effect analysis of water input in Tarim River. Sci in Chin Ser D-Earth Sci, 2004,
34(5): 475－482
2 Chen X Q. Taxonomy of Plant Chemistry (in Chinese). Beijing:
Higher Education Press, 1990, 53－66
3 Stess A C. Plant Taxonomy and Biosystematics. Beijing: Science
Press, 1986, 102－185
4 Smith P M, Hu C X (Translation). Taxonomy of Plant Chemistry.
Beijing: Science Press, 1980, 52－56
5 Zhang Y M. Seed morphology of Tamaricaceae in China arid areas
and its systematic evolution. Journal of Plant Resources and Environment (in Chinese), 1998, 7(2): 22－27
6 Zhang D Y, Yin L K, Pan B R. A review on the systematic study of
Tamarix L. Arid Zone Research (in Chinese), 2002, 19(2): 41－46
7 Feng Y, Yin L K. Study on organs morphology and its taxonomic
significance of Tamarix L. Arid Zone Research (in Chinese), 2000,
17(3): 40－45
8 Liu M T. Tamrix L. and its extending in the desert region of Xinjiang.
Journal of Desert Research (in Chinese), 1996, 16(4): 428－429
9 Giang Y Q, Zuo C X. Research on chemical components of
Tamarix L. Pharmacy Journal (in Chinese), 1988, 23(10): 749－
755.
Chinese Science Bulletin
Vol. 51 No. 9 May 2006
ARTICLES
10 Zhang Y R, Ling L Q. Research on the chemical composition of
Tamarix L. Herbal Medicine (in Chinese), 1989, 20(3): 4－5
11 Ji L. GC-MS analysis of Xiheliu chemical components. Chinese
Traditional Medicine (in Chinese), 1977, 22(6): 360－362
12 Ma R J, Wu S M. Anatomy and adaptation to sand environment of
6 Calligonum secondary Xylem. Acta Botanica Sinica (in Chinese),
1994, (11): 55－60
(3): 17－19
20 Shanghai Institute of Plant Physiology, Chinese Academy of Sciences and Shanghai Local Plant Physiological Institute. Experimentation Guide of Modern Plant Physiology. Beijing: Science
Press, 1998, 127
21 Zhu G L. Mensuration on free praline of plant body. Plant Physiology Communication (in Chinese), 1983, (4): 1－7
13 Zhai S H. Comparative observation of Tamarix L. Amplexicaul leaf
22 Zhao K F, Feng L T, Zhang S Q. Adaptive physiology of different
Morphostructure. Acta Botanica Sinica (in Chinese), 1983, 25(6):
ecotypes of Phragmites communis to salinity in the Yellow River.
42－44
Acta Ecologica Sinica (in Chinese), 1998, 18(5): 463－469
14 Zhang Y L, Xi Y Z. Pollen morphology of Calligonum and its
23 Yang S S, Gao J F, Li X J, et al. Leaf senescence and protective
meaning in stratum research. Acta Botanica Sinica (in Chinese),
enzyme system of spring wheat hybird. Scientia Agricultura Sinica
1997, 39(11): 1053－1057
(in Chinese), 2004, 37(3): 460－463
15 Wei Y, Tan D Y, Yin L K. The discussion on the anatomical struc-
24 Ruan X, Wang Q. Changes in content or release rate of 4 kinds of
ture of leaf and its taxonomic relationship of Tamaricaceae in
plant hormones in relation to the develop, ripening and senescence
China. Acta Bot Borcal—— Occident Sin (in Chinese), 1999, 19(1):
of fragrant pear fruit. Acta Phytophysiologica Sinica (in Chinese),
2000, 26(5): 402－406
113―118
16 Babitha M P, Bhat S G, Prakash H S, et al. Differential induction of
25 Yin L J, Shi D C. An analysis of a main salt of Alkalizing meadow
Superoxide Dismutase in Downy Mildew-Resistant and Suscepti-
steppe Na2CO3-harming factors to Leymus Chinensis. Acta Pra-
ble Genotypes of Pearl Millet. Plant Pathology, 2002, 51(4): 480－
taculturae Sinica (in Chinese), 1993, 2(1): 1－5
492
26 Chen Y N, Chen Y P, Li W H. Response of the accumulation of
17 Gries D, Zeng F J, Foetzkl S K, et al. Growth and water relations of
proline in the bodies of Populus Euphratica to the change of
Tamarix ramosissima and Populus euphratica on Taklamakan De-
ground water level at the lower reaches of Tarim River. Chin Sci
sert dunes in relation to depth to a permanent water table, plant.
Bull, 2003, 48(18): 1995－1999
Cell and Environment, 2003, 26(5): 725－736
27 Hindsa R S, Dhindsa P P, Thorpe T A. Leaf senescence, correlated
18 Huang P Y, Yao X L. The study on the migration and regeneration
with increased levels of membrane permeability and lipid peroxi-
of Tamarix community in Guerbantongute Desert. Acta Phy-
dation, and decreased levels of Superoxide Dismutase and
toecologica ET Geobotanica Sinica (in Chinese), 1991, 15(2): 151
Cata-lase. Jour Exp Bot, 1980, 32: 93
28 Chen Y N, Li W H, Xu H L, et al. The influence of groundwater on
－158
19 Zhao S J, Zou Q, Zheng G S. The measurement of chloroplast
pigment of modulated tobacco. China Tobacco (in Chinese), 1993,
www.scichina.com
www.springerlink.com
vegetation in the lower reaches of Tarim River, China. Acta
Geographica Sinica (in Chinese), 2003, 58(4): 542－549
1129