全 文 ：Journal of Forest ry Research, 14(2): 130-134 (2003) 130
Effect of overnight temperature on leaf photosynthesis
in seedlings of Swietenia macrophylla King
ZHANG Cheng-Jun1, Carlos Henrique B. de A. Prado2, ZU Yuan-Gang1, GUO Jia-Qiu3, Carlos Cesar Ronquim2,
Leonnardo Lopes Ferreira2
1 Key Laboratory of Forest Plant Ecology, Northeast Forestry University, Harbin 150040, P. R. China
2 Laboratory of Plant Physiology , Department of Botany, Federal University of Sao Carlos, SP, 13565-905, Brazil
3 The Second Affiliated Hospital of Harbin Medical University, Harbin 150086 , P. R. China
Abstract: After exposure of one-year old seedlings of Swietenia macrophylla to an overnight temperature (13 °C, 19 °C, 25 °C,
31 °C or 35 °C), the leaf net photosynthetic rate (Pn) was researched through measuring photosynthetic light-response curves at
360 mmol·mol-1 CO2, and photosynthetic CO2-response curves at light-saturated intensity (1500 mmol·m-2 ·s-1). The optimal
temperature for photosynthesis measured at 360 mmol·mol-1 CO2 was from 25 °C to 31 °C, but which was from 31°C to 35 °C at
saturating CO2 concentration. At temperature of below 25 °C, the decline in Pn was mainly due to the drop in carboxylation
efficiency (Ce), while as temperature was over 31 °C, the reduction in Pn resulted from both decrease in Ce and increase in leaf
respiration. The CO2-induced stimulation of photosynthesis was strongly inhibited at temperatures below 13 °C. The results
showed that, the leaf photosynthesis of tropical evergreen plants should not be accelerated at low temperature in winter season
with elevated CO2 concentration in the future.
Keywords: Apparent quantum yield; Carboxylation efficiency; CO2-induced stimulation; Swietenia macrophylla King;
Leaf temperature
CLC number: Q945.11 Document code: A Article ID: 1007-662X(2003)02-0130-05
Introduction1
Leaf photosynthesis is one of the most thermal sensitive
processes providing an indicator for functional limitations
imposed particularly by air temperature (Harley 1995). At
temperatures too high or too low the photosynt hetic yields
decrease steadily until CO2 uptake ceases (Larcher 1994) .
Plants are exposed to only a narrow range of temperatures
at most tropic regions, so even smaller changes in
temperature might be equal or more important in the tropics
than at temperate latitudes (Hogan et al. 1991). However,
very little attention has been directed to the photosynthetic
response of tropical trees to the interactions between
temperature and irradiance, as well as between
temperature and CO2 concentrations (Hogan et al. 1991).
Big-leafed Mahogany (Swietenia macrophylla King
( Maliaceae)) is distributed naturally from the south of
Mexico throughout Central and South America to Bolivia
and Brazil, including large portions of the Amazon Basin. It
is one of the most valuable plants on the international
market because of the beauty and durability of its wood.
Increasing demand for this valuable timber has r esulted in a
severe decline in the wild population of this species
(Schmidt et al. 2000). Thus, it is necessary to determine its
ecophysiological properties, especially to predict its
possible response in the future with increasing CO2 and
Biography: ZHANG Cheng -Jun (1968-), male, Lecturer in Key Laboratory
of Forest Plant Ecology, Northeast Forestry University, Harbin 150040, P. R.
China.
Received date: 2003-03-11
Responsible editor: Zhu Hong
temperature.
This work was to determine the response of net
photosynthetic rate in Swietenia macrophylla seedlings to
leaf temperature, through measuring photosynthetic
ligh-response curves and photosynthetic CO2-respons
curves at light-saturated intensity, following an overnight
temperature (13 °C, 19 °C, 25 °C, 31 °C or 35 °C, which is
similar to the annual air temperature scope in the natural
habitat of this species). Considering CO2-temperature
interaction we predicted that the optimal temperature of
photosynthesis in this tropical species might also be shifted
upward at high CO2 concentration like most temperate
plants.
Materials and methods
The one-year-old seedlings of Swietenia macrophylla
were cultivated in polystyrene foam boxes containing 32 kg
sifted cerrado soil. Five boxes of seedlings were used for
experiment, two seedlings per box. They were grown in a
greenhouse with diurnal temperature (25±5) °C, night
temperature (18±3) °C and relative humidity (RH,
(60±10)%). During the experimental period the seedlings
cultivated in the soil was irrigated well once a week.
Preliminary experiment showed that photosynthesis
measured at simi lar conditions was similar for leaves with
similar age in these seedlings. Before temperature
treatment, two boxes were wrapped with a thick synthetic
mantle in order to maintain the soil temperature constant.
Thus, only the aerial parts of plants were exposed to the
desired temperature. The two boxes were placed into an
ZHANG Cheng-Jun et al. 131
incubator (Model NT-708, Piracicaba, Brazil) at a
temperature set as 13 °C, 19 °C, 25 °C, 31 °C or 35 °C. The
treatment started from 19:00 to 7:00. The interval between
two treatments was at least one week for each box.
Leaf photosynthesis was conducted in a special chamber
with similar temper ature as the treating level in the following
morning from 7:00 to 9:00. The healthy mature leaves with
similar age were chosen to measure photosynthet ic
light-response curves using a portable infra-red gas
analyzer (LCA-4 model, ADC, Hoddesdon, UK) with a
Parkinson Leaf Chamber (PLC4-N). The light started from
2000 mmol·m-2·s- 1 to 0 mmol·m- 2·s-1, provided by a
Portable Light Unit (PLU-002, ADC) mounted on the head
of the PLC4 -N. The leaf temperature was maintained by a
microclimate controller (PLC4-TC, Peltier cooler/heater
system, ADC) at the night treating temperature. Six to
seven stable values were recorded at one light level. To
prevent stomatal closure, relative humidity in the leaf
chamber was maintained at 45 % obtained from the
preliminary experiment.
Measurements of leaf gas exchange as a function of CO2
concentrations (Pn/Ca and Pn/Ci curves) were carried out by
an ADC gas diluter (GD-602-GC), which can produce a
series of intermediate CO2 concentrations from a single
cylinder containing 1900 mmol·mol-1 CO2. Eleven levels of
CO2 concentration were available, varying from 1900
mmol·mol- 1 to 0 mmol·mol-1 and diluting at 10 % intervals.
The light was maintained at a saturating value of 1500
mmol·m-2·s-1 during Pn/CO2 curves according to
photosynthetic light-response curves previously obtained.
The measurement was still made in the special chamber
and the control of leaf temperature was similar to the
measurement of photosynthetic light-response curves.
The non-linear adjustment of photosynthetic
light-response curves followed the model described by
Prado et al. (1997).
Pn =P1´ )e1( )3(2 PxP -´-- (1)
where P1 is the light-saturated photosynthetic rate (Pnmax,
mmol·m-2·s-1), P2 is a constant, Pn is the actual
photosynthetic rate (mmol·m-2·s- 1), c is the photosynthetic
photon flux density (mmol·m-2·s-1), P3 is the light
compensation point ( Lcp, mmol·m-2·s-1), and e is the natural
logarithm. The light saturation point (Lsp, mmol·m-2·s-1) was
calc ulated at 90 % of Pnmax. Leaf respiration in the dark (Rd)
was obtained at 0 mmol·m-2·s-1 photosynthetic photon flux
density. The estimation of apparent quantum yield of CO2
assimilation (F) was obtained from the following equation
derived from the inclination of the straight line in the first
linear phase of the curve obtained from equation (1), (Prado
et al. 1997).
F =P1´ P 2´ 32e PP ´ (2)
Similarly, the two equations were also used to fit Pn/Ca
and Pn/Ci responses and to obtain the corresponding
parameters: light- and CO2-saturated photosynthetic rate
(Pnmax, mmol·m- 2·s-1), CO2 saturation point (Csp,
mmol·mol-1), CO2 compensation point (Ccp, mmol·mol-1),
carboxylation efficiency (Ce, mol·m- 2·s-1), and leaf
respiration in the light (Rl, mmol·m-2·s-1).
Results
At 360 mmol·mol-1 CO2, the response of Pn to
photosynthetic photon flux density varied depending on leaf
temperature (Fig. 1). The curve of Pnmax to leaf temperature
showed a typical shape with an optimal maximum, and
supra- and sub-optimal depression (Fig. 2). The optimal
temperature for net photosynthetic rate was observed
between 25 °C and 31 °C. As leaf temperature decreased
from 25 °C to 13 °C, Pnmax decreased. Supra-optimal
temperature above 31 °C inhibited leaf photosynthesis.
Fig. 1 Net photosynthesis (Pn) as a function of
photosynthetic photon flux density in Swietenia macrophylla
seedlings following overnight leaf temperature treatment.
Each curve was obtained by fitting the data of two or three replicates for
each temperature level.
The variation in Lsp response to temperature was
positively r elated to that in Pnmax response (r=0.88, p<0.05)
(Fig. 2B). The relatively high values of Lsp were observed at
25 °C and 31°C at the higher values of Pnmax, while the
lowest value occurred at 13 °C with the lowest value of
Pnmax. Rd increased with increasing temperature (Fig. 2E),
which resulted in a paralleling response of Lcp (Fig. 2C). F
0 500 1000 1500 2000
0
10
20
30
35
o
C
Pn max=8.40
r
2
=0.98
Photosynthetic photon flux density /m mo l·m -2·s -1
0
10
20
30
31
o
C Pn max=10.96
r
2
=0.97
0
10
20
30
25
o
C
Pn max=11.44
r
2
=0.99
P n
/
m
m
ol
·
m
-2
·
s-
1
0
10
20
30
19
o
C P nmax=9.27
r
2
=0.98
0
10
20
30
13
o
C Pnmax=5.28
r
2
=0.90
Journal of Forest ry Research, 14(2): 130-134 (2003) 132
13 19 25 31 37
0.0
0.8
1.6
E
R d
/
m
m
ol
· m
-2
·
s-
1
T leaf /
o
C
0.020
0.024
0.028
0.032
0.036
aaa
D
F
0
15
30
45
60
C
L c
p /
m
m
ol
· m
-2
·
s
-1
450
600
750
900
1050
aa
B
L s
p
/
m
m
ol
· m
-2
·
s
-1
4
6
8
10
12
aa
A
P n
m
ax
/
m
m
ol
· m
-2
·
s
-1
increased from 13 °C to 19 °C, but decreased from 19 °C to
25 °C and then maintained relatively constant from 25 °C to
35 °C (Fig. 3D).
Fig. 2 The temperature response of light-saturated
photosynthetic rate (Pnmax), light saturation point (Lsp), light
compensation point (Lcp), apparent quantum yield (Ф ) and
respiration in the dark(Rd) in Swietenia macrophylly seedlings.
All parameters were obtained from photosynthetic light -response
curves. Vertical bars indicate the standard deviation. The same small
letters below symbols indicate that the difference in the values in every
row figure are not significantly at the level of P<0.05.
At different overnight temperatures, the photosynthetic
responses, as a function of Ci at a saturating light of 1500
mmol·m-2·s-1, are shown in Fig. 3. At light- and
CO2-saturated conditions, within the experimental
temperature ranges, the leaf photosy nthesis rate increased
with increasing temperature from 13 °C to 31 °C, the
optimal temperature was selected between 31 °C and 35
°C (Fig. 3 and 4A). The Csp, as well as Ccp, decreased from
13 °C to 19 °C, and then increased from 19 °C to 35 °C (Fig.
4B-C). Ce inc reased from 13 °C to 31 °C, and was inhibited
at 35 °C. Rl at a light of 1500 ìmol·m- 2·s-1 increased as
temperature rose from 13 °C to 35 °C.
Discussion
In this work, different overnight leaf temperatures caused
large variation in F in the following day. Ehleringer et al.
(1993) pointed out that two environmental parameters most
likely to influence any change in F would be temperature
and irradiance during seedling growth. In this work,
therefore, variation in F was mainly attributable to different
overnight leaf temperatures. Based on theoretical
expectation, F should be decreased with increasing
temperature from 15 °C to 40 °C (Long 1991), which has
been confirmed by some studies (Cannell et al. 1998).
However, the F increased between 13 °C and 19 °C, and
was stable between 25 °C and 35 °C in the present work.
The results are contrary to such a theoretical expectation
(Fig. 2D). The conflict between theoretical expectation and
exper imental results for F was also observed in Glycine
max by Harley et al. (Leegood et al. 1996). They found that
F did not decrease until temperatures exceeded 25 °C.
This kind of phenomenon may be explained by the
differences in prevailing growth temperatures. The values
of F decreased as leaf temperature decreased from 19 °C
to 25 °C (Fig. 2D), which may be mainly attributable to
photorespiration (Fig. 3E) resulting in reduction in
assimilation power (Long 1991; Cannell et al. 1998).
Fig. 3 Net Photosynthetic rate (Pn) as a function of leaf
intercellular CO2 concentration (Ci) in Swietenia macrophylla
seedlings following overnight leaf temperature treatment. All
curves were made at 1500 ìmol·m-2·s-1 photosynthetic photon flux
density, 45 % RH. Each curve was obtained by fitting the data of two or
three replicates for each temperature level.
0 500 1000 1500 2000
0
10
20
30
Pnmax=29.35
r
2
=0.95
35
o
C
C i /mmol·mol
-1
0
10
20
30
31
o
C
Pnmax=29.93
r
2
=0.99
0
10
20
30
25
o
C
Pnmax=24.37
r
2
=0.97
P n
/m
m
ol
·
m
-2
·
s
-1
0
10
20
30
Pnmax=14.29
r
2
=0.98
19
o
C
0
10
20
30
13
o
C Pnmax=7.61
r
2
=0.93
ZHANG Cheng-Jun et al. 133
Fig. 4 The temperature response of photosynthetic rate (Pnmax)
at light- and CO2-saturated points, CO2 saturation point (Csp),
CO2 compensation point (Ccp), carboxylation efficiency (Ce )
and respiration in the light (Rl ) in Swietenia macrophylla
seedlings. The values of Pnmax, Ce and Rl were obtained from Pn/Ci
curves, while Csp and Ccp values from Pn/Ca curves (omitted). Vertical
bars indicate the standard deviation.
The Ce increased as temperature rose from 13 °C to 31
°C (Fig. 4D), which may be attributable to increased
capacity of the enzymes of carbon assimilation (Leegood et
al. 1996). In general, increasing temperature increases not
only the carboxylation capacity of Rubisco, which has a
positive effect on Ce, but also the Km (Michaelis-Menten
constant) of Rubisco for CO2, which has a negative effect
on Ce (Edwards 2002, personal communication). An
additional negative effect on Ce may result from the
increase in the competitive capacity of O2 for Rubisco
which could be reflected by increased leaf respiration (Fig.
2E) with increasing temperature. The increase in Ce
between 13 and 31 °C showed that the positive effect of
increasing temperature was greater than its negative effect
on Ce in this study. The Ce at 35 °C was reduced most
probably because higher leaf temperature decreased the
CO2 specificity of Rubisco and increased O2 specificity of
Rubisco in favor of oxygenase (Bowes 1991).
It has been well documented that the temperature
optimum for photosynthesis is always associated with the
temperature range prevailing in the native habitat of plants
(Björkman et al. 1972; Chabot et al. 1976; Mooney et al.
1976). In this work, measured at ambient CO2, the optimal
temperature for leaf net photosynthesis was between 25 °C
and 31 °C (Fig. 2A), which is within the range of optimal leaf
photosynthetic temperature for most tropical plants
(Larcher 1994).
Light-saturated photosynthetic rate is determined by
carboxylation and RuBP-regeneration capacities (Mooney
et al. 1976). Inhibition of carboxylation capacity was directly
related to inhibition of photosynthesis and could have a
significant effect on plant growth and development (Law et
al. 1999). In this work, measured at ambient CO2 and
temperatures between 25 °C and 31°C (Fig. 2A), the
highest photosynthesis was simultaneously with the higher
values both in Ce and Lsp (Fig. 2D and 3D). Therefore, the
higher value of Pnmax can be entirely attributable to the
highest carboxylation capacity of Rubisco because at low
Ci and high light (> 1000 mmol·m-2·s-1) photosynthesis is
likely to be limited almost exclusively by Rubisco (Higuchi
et al. 1999).
It is well documented that declines in photosynthesis
following a low temperature in dark or light have been
attributed partly to decline in Rubisco activity (Allen et al.
2001), while high temperatures inhibit photosynthetic CO2
fixation and damage photosynthetic electron transport,
particularly at the site of PSII (He et al. 2001). Compared
with the value of Pnmax at the optimal temperature, the
photosynthesis decreased significantly with decreasing leaf
temperature from 25 °C to 13 °C (Fig. 2A). The decrease in
Pnmax at sub-optimal temperature mainly resulted from the
substantial decline in Ce by lower leaf temperature (Fig. 4D).
In contrast, inhibition of Pnmax at supra-optimal temperature
was mainly due to bo th reduction in carboxylation capacity
of Rubisco and the sharp increase in leaf photorespiration
(Fig. 2A and 3D-E).
The results here also showed that high CO2
concentr ation increased leaf photosynthesis and that its
stimulatory magnitude was dependent on leaf temperature.
At instantaneous high CO2 concentration, the increase in
photosynthesis in C3 plants is usually attributed to
increased intercellular CO2 concentration which leads to
increase both in Ce (Drake et al. 1997) and in F (Cannell et
al. 1998), and decrease in photorespiration (Law et al.
1999).
At saturating light intensity, increasing leaf temper ature
from 13 °C to 31 °C resulted in an increase in
photosynthetic capac ity, Ce and leaf respiration. The higher
values of Pnmax were observed betw een 31 °C and 35 °C
(Fig. 3 and 4A), suggesting that high CO2 resulted in an
upward shift in the photosynthetic temperature optimum of
this species studied. The result is consistent with our
prediction. The CO2-induced upward shifts in optimal
temperatures for photosynthesis were also reported with
other C3 plants (Sheu et al. 1999) and consistent with
theoretical prediction (Mitchell et al. 2000). Although high
temperatures alter the CO2/O2 specificity of Rubisco in
favor of oxygenase, increasing the CO2 concentration
reduces the oxygenase activity of Rubisco, favoring
13 19 25 31 37
0
2
4
6
E
R
l /
m
m
ol
·
m
-2
·
s
-1
Tleaf /
oC
0.00
0.06
0.12
0.18 D
C
e /
m
ol
·
m
-2
·
s
-1
0
30
60
90
C
C
cp
/
mm
ol
·
m
ol
-1
400
800
1200
1600
2000 B
C
sp
/
m
m
ol
·
m
ol
-1
0
10
20
30 A
P
nm
ax
/
mm
ol
·
m
-2
·
s-
1
Journal of Forest ry Research, 14(2): 130-134 (2003) 134
increased net CO2 fixation and as a consequence CO2
enrichment increases the temperature optimum for
photosynthesis (Bowes 1991). These results also confirm
the prediction of Long (1991) that the temperature optimum
of Pnmax must increase with ambient CO2 increment. The
shift in optimal temperatures underlies that the importance
of considering rise in atmospheric CO2, not simply as a
factor which increases photosynthetic rate, but also as a
variable that modifies the response to temperature (Long
1991), and which confirms that high CO2 concentration can
diminish high temperature inhibition of photosynthesis
(Hogan et al. 1991).
It is also apparent that the magnitude of CO2-induced
increase in photosynthesis at higher temperatures is
greater than that at lower temperatures (Fig. 2), which is
consistent with the concept that inhibition of oxygenation by
rising CO2 concentration and hence increase in net
photosynthesis will have its greatest effect at higher leaf
temperatures because CO2- induced changes in
photorespir ation and Rubisco activity are greater at high
than at low temperatures (Greer et al. 2000). Similarly, this
result also shows that at lower temperatures, the
stimulation effect of high CO2 can be reduced (Fig. 1 and
Fig. 3), which further confirms that low temperatures will
necessarily reduce the relative stimulation of
photosynthesis caused by rising atmospheric CO2 (Bunce
2000). And this also indicates that CO2-temperature
interactions is smaller at lower temperatures (Cannell et al.
1998). Similar results were observed with loblolly (Pinus
taeda), (Hymus et al. 1999). Hymus et al. (1999) pointed
out that elevated CO2 concentration might add a further
stress to overwintering evergreen vegetation in temperate
regions. Our result showed that such an effect may also
occur in tropical regions.
According to the inhibition of CO2- induced stimulation of
photosynthesis by low temperature and the upward shift in
temperature optimum by increasing Ca, it is easy to
conclude that the winter stress on evergreen foliage in
tropics might be greater than in temperate regions because
the sub-optimal temperature range for photosynthesis will
be wider in tropical area than in temperate regions in terms
of the degree of the increase in temperature in the future.
Acknowledgements
This study was carried out when Zhang Chengjun as a
visiting scholar was at Federal University of Sao Carlos,
Brazil from 2001 to 2002, which was supported by both of
CAPES of Brazil and of the Chinese Scholar Council. The
authors thanks Mr. Carlos Casali for technique assistance.
References
Allen, D.J. and Ort, D.R. 2001. Impacts of chilling temperatures on
photosynthesis in warm-climate plants [J]. Trends Plant Sci., 6:36-42.
Björkman, O., Pearcy, R.W., Harrison, A.T. et al. 1972. Photosynthesis
adaptation to high temperatures: a field study in Death valley,
California [J]. Science, 175 :786-789.
Bowes, G. 1991. Growth at elevated CO2: photosynthetic responses
mediated through Rubisco [J]. Plant Cell Environ, 14:795-806.
Bunce, J.A. 2000. Acclimation to temperature of the response of
photosynthesis to increased carbon dioxide concentration in
Taraxacum officinale [J]. Photosynth Res., 64: 89-94.
Cannell, M.G.R. and Thornley, J.H.M. 1998. Temperature and CO2
response of leaf and canopy photosynthesis: a clarification using the
non-rectangular hyperbola model of photosynthesis [J]. Annals of
Botany, 82: 883-892.
Chabot, B.F. and Lewis, A.R. 1976. Thermal acclimation of
photosy nthesis in northern red oak. [J]. Photosynthetica, 10:
130-135.
Drake, B.G., Gonzalez-Meler, M.A. and Long, S.P. 1997. More efficient
plants? A consequence of rising atmospheric CO2 [J]. Annu Rev
Plant Physiol Plant Mol Biol., 48: 607-637.
Ehleringer, J. and Pearcy, R.W. 1993. Variation in quantum yield for
CO2 uptake among C3 and C4 plants [J]. Plant Physiol., 73: 555-559.
Greer, D.H., Laing, W.A., Campbell, B.D., et al. 2000. The effect of
perturbations in temperature and photon flux density on the growth
and photosynthetic responses of five pasture species to elevated
CO2 [J]. Aust. J. Plant Physiol., 27:301-310.
Harley, P.C. 1995. Modeling leaf level effects of elevated CO2 on
Mediterranean sclerophylls [J]. Ecological Studies, 117:35-57.
He, J. and Lee, S. 2001. Relationship among photosynthesis,
ribulose-1,5-bisphosphate carboxylase (Rubisco) and water relations
of the subtropical vegetable Chinese broccoli grown in the tropics by
manipulation of root -zone temperature [J]. Environ Exp Bot. ,
46:119-128.
Higuchi, H., Sakuratani, T. and Utsunomiya, N. 1999. Photosy nthesis,
leaf morphology, and shoot growth as affected by temperatures in
cherimoya (Annona cherimola Mill.) trees [J]. Sci Hort., 80:91-104.
Hogan, K.P., Smith, A.P. and Ziska, L.H. 1991. Potential effects of
elevated CO2 and changes in temperature on tropical plants [J]. Plant
Cell Environ, 14: 763-778.
Hymus, G.J., Ellsworth, D.S., Baker, N.R., et al. 1999. Does free-air
carbon dioxide enrichment affect photochemical energy use by
ev ergreen trees in different seasons? A chlorophyll fluorescence
study of mature loblolly pine [J]. Plant Physiol, 120:1183-1191.
Larcher, W. 1994. Photosynthesis as a tool for indicating tem perature
stress events [C]. In: Schulze, E. and Caldwell, M.M. (Eds)
Ecophysiology of Photosynthesis. Berlin: Springer, pp. 261-277.
Law, R.D. and Crafts-Brandner, S.J. 1999. Inhibition and acclimation of
photosynthesis to heat stress is closely correlated with activation of
ribulose-1, 5-bisphosphate carboxylase /oxygenase [J]. Plant Physiol,
120:173-181.
Leegood, R.C. and Edwards, G.E. 1996. Carbon metabolism and
photorespiration: Temperature dependence in relation to other
env ironmental factors [C]. In: Baker, N.R. (Eds) Photosynthesis and
Environment. The Netherlands: Kluwer Academic Publishers, pp.
191-231.
Long, S.P. 1991. Modification of the response of photosynthetic
productivity to rising temperature by atmospheric CO2 concentrations:
Has its importance been underestimated [J]? Plant Cell Environ,
14:729-739.
Mitchell, R.A.C., Theobald, J.C., Parry, M.A.J., et al. 2000. Is there
scope for improving balance between RuBP-regeneration and
carboxylation capacities in wheat at elevated CO2 [J]? J. Exp. Bot.,
51:391-397.
Mooney, H.A., Ehleringer, J. and Berry, J. A. 1976. High phot osynthetic
capacity of a winter annual in Death Valley [J]. Science, 194:322-323.
Prado, C.H.B.A. and Moraes, J.A.P.V. 1997. Photosynthetic capacity
and specific leaf mass in twenty woody species of cerrado vegetation
under field conditions [J]. Photosynthetica, 33: 103-112.
Schmidt, L. and Joker, D. 2000. Swietenia macrophylla King [J]. Seed
Leaflet, 30:1-2.
Sheu, B.H. and Lin, C.K. 1999. Photosynthetic response of seedlings of
the sub-tropical tree Schima superba with exposure to elevated
carbon dioxide and temperature [J]. Environ. Exp. Bot., 41:57-65.
Chinese Abstracts iii
纯 CO2萃取的化感物质。表 3 参 20。
关键词：杉木；自毒作用；超临界 CO2萃取；生物评价
03-02-006
几种经济林树种根系分泌物主要成分的 GC-MS分析 /孙浩元，王玉柱，
杨丽（北京市农林科学院林业果树研究所，北京 100093,中 国 ）
//Journal of Forestry Research.-2003,14(2): 127-129.
本研究采用盆栽栽培技术，对包括板栗、杏、柿子、桃、核桃、
梨和苹果等 7个经济林树种的根系分泌物进行提取和分离，通过色谱
/质谱（GC-MS）分析方法对其主要成分进行了检测。按照“中国环
境优先污染物黑名单”和美国环保署标准，检测到的 200 余种有机分
泌物中有 3种属于优先控制污染物，即萘、二甲苯和邻苯二甲酸二丁
酯。研究结果为密云水库上游水源保护区内选择适宜发展的低污染经
济林树种提供了参考依据。图 1表 2参 11。
关键词：经济林；根系分泌物；成分
03-02-007
温度对大叶桃花心木（ Swietenia macrophylla King）幼苗叶片的光
合影响/张成军（东北林业大学森林植物生态学教育部重点实验室，哈
尔 滨 150040， 中 国 ）， Carlos Henrique B. de A. Prado
（ Laboratory of Plant Physiology, Department of Botany,
Federal University of Sao Carlos, SP, 13565-905, Brazil），祖元
刚 （ 东 北 林 业 大 学 森 林 植 物 生 态 学 教 育 部 重 点 实 验 室 ， 哈 尔 滨
150040，中国）， 郭 佳 秋(哈尔滨医科大学第二附属医院，哈尔滨
150086， 中 国 )，Carlos Cesar Ronquim，Leonnardo Lopes
Ferreira （ Laboratory of Plant Physiology, Department of
Botany, Federal University of Sao Carlos, SP, 13565-905,
Brazil） //Journal of Forestry Research.-2003,14(2): 130-134.
本文研究了大叶桃花心木（Swietenia macrophylla King）一
年生幼苗在经过夜温处理后的 光响应曲线和在饱和光强下的 CO2 反
应曲线。结果表明：在大气 CO2浓度下，叶片的最佳光合作用温度在
25-31℃之间，而在饱和 CO2浓度下为 31-35℃。在 25℃以下光合速
率开始降低，主要是由于羧化效率的降低，而当温度超过 31℃时，光
合速率下降，是因为羧化效率的降低和呼吸速率的增加。 CO2浓度对
光合的促进作用在低温下受到抑制，这意味着未来在 CO2浓度增高的
情况下，高浓度的 CO2对热带常绿植物光合的促进在冬天低温情况下
表现不十分明显。图 4 参 23。
关键词：表观量子产量；羧化效率；CO2诱导；大叶桃化心木；叶片
温度
03-02-008
京郊农田防护林景观生态评价 — —以北京大兴县北藏乡为例 /李春平，
关文彬，范秀珍，赵廷宁，陈建刚，孙保平 (北京林业大学水土保持部
级 重 点 实 验 室 ， 北 京 100083 ， 中 国 ) //Journal of Forestry
Research.-2003,14(2): 135-140.
以北京市大兴县北藏乡为例，根据防护林学和景观生态学的原
理，结合野外调查与地理信息系统 Citystar 和遥感等技术，从林带和
林网两个尺度对防护林体系的布局和结构的合理性进行分析和评价。
结果表明：该乡主林带过窄，宽度是 3-12m；副林带过宽，宽度是
3-27.1m，树种较单一；整个景观布局不够合理。建议更新时应考虑
多种适宜树种混交 , 加宽主林带，适当减少副林带的宽度 ,应采用中间
乔木两侧配用灌木的混交方式。建议更新或改造后的林网景观结构应
为：闭合网格数应达到 13个/km2，最少林带条数应达到 34条/km2。
实践证实，利用景观生态学原理，结合 GIS 和遥感技术为进行农田防
护林网景观结构的改造提供了有效的方法。表 6 参 14。
关键词：北京；防护林；林带结构；生态景观；评价
03-02-009
FORESTAR:东北地区多目标森林经营的决策支持系统/邵国凡，代力民，
李英善（中国科学院沈阳应用生态研究所，沈阳市文化路 72 号
110015），刘永敏（国家林业局天然林保护管理中心，北京市 100714），
柏广新（延边朝鲜族自治州林业管理局，吉林省延吉市 133001）
//Journal of Forestry Research.-2003,14(2):141-145.
我国林业过去曾经实行过大砍大造的方针，导致全国范围的生
态灾难和林 区的经济困境。当前正在实施的天然林保护工程和退耕
焕还林工程是在我国山地森林应用生态系统管理的良好时机。针对
长白山地区天然林的保护与经营，我们建立了一个决策支持系统，
简称为 FORESTAR。它是以林业局为单位、用 GIS 框架下的森林
资源清查数据建立的。最初的版本包括两个子模块：森林采伐设计
和森林恢复经营。在每个子模块下，用户可以比较各种决策条件下
的效果，以便从中选优。这个决策支持系统可以用来帮助各级林业
工作者实现上下一致的、多目标的森林经营管理规划。图 2 参 17。
关键词：林业可持续发展；生态系统管理；中国林业政策；决策支
持系统；温带混交林
03-02-010
生态系统健康：战略环境评价的生态可持续性目标 /陈昆玉（西安交通
大 学 管 理 学 院 ， 西 安 710049， 中 国 ） //Journal of Forestry
Research.-2003, 14(2): 146-150.
战略环境评价与生态系统健康是两种新兴的环境管理思想。本研
究的目的在于通过对相关文献进行综述，探讨战略环境评价的生态可
持续性目标，以及生态系统健康的内涵，并试图探寻二者之间存在的
关联。研究发现，好的战略环境评价其生态可持续性原则应当具有明
晰的内涵以及一般性的评价体系。根据生态系统健康的内涵，构建了
生态系统健康评价框架，把它引入战略环境评价作为战略环境评价的
生态可持续性目标定位，能有效引导决策者制定合理的本土化评价方
案。最后，讨论了基于生态系统健康目标的战略环境评价的基本原则
与程序。图 2参 12。
关键词：环境影响评价；战略环境评价；生态系统健康
03-02-011
中国广东红树林资源现状与保护对策 /韩维栋（湛江海洋大学园林系，
湛江 524088，中国）//Journal of Forestry Research.-2003,14(2):
151-154.
根据 2001年对广东省红树林资源现状调查和作者过去 5年的野
外调查结果，中国广东有 9084.0 hm2成熟红树林分布于其沿海 100
余处，占中国该类型红树林面积的 41.4%，由 28科 50种树种组成，
其中以白骨壤群落最占优势。各红树林群落多呈高密度而低矮群落外
貌，如林地森林覆盖率大于 0.7 的红树林林地面积占全省红树林面积
的 68.0%；树木高度低于 2 m 的红树林群落面积是全省红树林面积的
77.8%。1950 以来，农田围垦、水产养殖池和城市扩建等原因使原有
的 54.6%的红树林面积消失。本文提出当前红树林保护力量仍然薄
弱，必须采取有力保护管理措施，加强立法、科研与保护宣传，让当
地居民参与红树林保护管理事务的决策。表 5参 11。
关键词：广东；红树林；资源现状；保护
ii