Directory UMM :Data Elmu:jurnal:T:Tree Physiology:Vol15.1995:

Tree Physiology 15, 167--174
© 1995 Heron Publishing----Victoria, Canada

Influence of foliar N on foliar soluble sugars and starch of red spruce
saplings exposed to ambient and elevated ozone
ROBERT G. AMUNDSON,1,2 ROBERT J. KOHUT1 and JOHN A. LAURENCE1
1

Boyce Thompson Institute for Plant Research, Cornell University, Tower Road, Ithaca, NY 14853, USA

2

Present address of corresponding author:1616 SW Harbor Way #403, Portland, OR 97201, USA

Received June 14, 1994

Summary Red spruce (Picea rubens Sarg.) trees growing at
high elevation in the northeastern United States have experienced decline in recent years but seedlings have proved to be
relatively tolerant of a wide range of environmental stresses in
controlled studies. One possible reason for the wide tolerance
to stress in seedlings is their inherently large pool of carbohydrate reserves, which is available for maintenance during and

regrowth after periods of stress. We tested for the effects of
foliar N and exposure to ozone on foliar carbohydrate reserves
of 20-year-old naturally regenerated saplings. The trees were
maintained in native soil in 360-l containers for 5 years before
the experiment. The year before the experiment, trees were
fertilized with N,P,K to provide a population of trees from N
deficient to N sufficient. As foliar N decreased below 0.9%,
length of current-year shoots and specific needle area of current-year needles declined. Foliar N concentration was correlated with foliar sugar and starch concentrations, but
relationships varied with time of year. Before bud break, foliar
carbohydrates and N, in general, were positively correlated,
and date of bud break was delayed in N-deficient trees. During
active growth, foliar soluble sugars and N were positively
correlated, but starch concentrations were negatively correlated with N. By late September, neither starch nor sugar
concentration was correlated with N concentration. Ozone and
foliar N concentrations did not interact to change foliar carbohydrate concentrations or shoot and needle growth in this
relatively short-term study.
Keywords bud break, carbohydrate reserves, Picea rubens,
shoot length, specific needle area, stress tolerance.

Introduction

Plants of low-resource environments have slow growth, low
potential for resource capture, effective chemical defenses, and
a high capacity for storage reserves (Grime 1977, Chapin
1991). Storage reserves are essential for survival in environments where resources are low or highly variable because they
allow for maintenance during and growth after periods of

resource limitation. But the cost of maintaining reserves is
reduced growth (Chapin et al. 1990).
Retention of leaves for longer than one growth period, evergreenness, has been proposed as an adaptation to resource
limited systems that allows plants either to take advantage of
‘‘suitable conditions during generally unfavorable periods’’
(Moore 1984) or to store limiting resources such as nitrogen
(Rundel and Parsons 1980). In temperate and boreal forests,
survival of evergreen foliage through the winter depends on the
development of cold tolerance, which is associated with
changes in the quality and quantity of foliar carbohydrates
(Senser et al. 1971). The ability of photosynthetic tissue to
survive winter provides evergreen trees with the capacity to fix
and store carbon before bud break. At bud break these carbon
reserves are available for rapid growth of new foliage.

Foliar carbohydrate reserves of evergreen trees change seasonally with changes in photosynthetic activity, growth and
cold tolerance (Little 1970, Senser et al. 1971, Kramer and
Kozlowski 1979). These changes in foliar carbohydrates reflect changes in source--sink strengths and are most predictable
in evergreens such as red spruce (Picea rubens Sarg.) that have
preformed shoots (fixed growth) and one annual period of
shoot growth (Friedland et al. 1988, Alscher et al. 1989,
McLaughlin et al. 1990, Amundson et al. 1992). For example,
in the spring, newly fixed photosynthate is stored in stems and
foliage as starch because of low sink strength and can, at that
time, account for up to 30% of foliar dry weight (Alscher et al.
1989). By autumn, total soluble sugar content increases to
above 10% of needle dry weight, whereas starch content drops
nearly to zero (Alscher et al. 1989). This shift in the allocation
of carbohydrates is associated with the cold hardening process
(Senser et al. 1971).
Because of the importance of foliar carbohydrate reserves
for maintenance during and growth after periods of resource
limitation, any stress that reduces carbohydrate reserves could
potentially affect the tree’s ability to respond to subsequent
stress. Many environmental stresses have been shown to alter

foliar carbohydrate contents. The air pollutant, ozone, reduces
foliar starch concentrations of red spruce (Amundson et al.

168

AMUNDSON, KOHUT AND LAURENCE

1991, Woodbury et al. 1992) and other evergreens (Meier et al.
1990, Paynter et al. 1991) as does water stress (Meier et al.
1990, Amundson et al. 1993). In contrast, N deficiency is
frequently associated with elevated foliar starch concentrations in angiosperms (Waring et al. 1985, Chapin et al. 1986,
Pell et al. 1990, Chapin 1991, Thompson et al. 1992) and
gymnosperms (Ericsson 1979, Adams et al. 1986), presumably
because low N availability reduces starch demand and growth
faster than the capacity to fix carbon (Chapin 1991).
Many forested ecosystems are N limited (Vitousek 1982)
and are exposed seasonally to elevated ozone (McLaughlin
1985). Because these two stresses have opposite effects on
foliar carbohydrates, the stresses should interact. Pell et al.
(1990) exposed radish (Raphanus sativa L.) to varying concentrations of ozone and N and found interactive effects on foliar

carbohydrates. They also observed a strong positive relationship between the ratio of sink to source mass and the amount
of total nonstructural carbon in the sink organ, suggesting a
functional relationship between carbohydrate concentrations
in sink organs and relative strengths of source and sink.
The primary goals of the present study were to determine if
foliar N alters foliar carbohydrate reserves of red spruce and,
if so, to test if foliar N interacts with ozone to change these
reserves. To test for effects of foliar N on foliar carbohydrate
reserves, foliar N and carbohydrates of a group of red spruce
saplings with a wide range of foliar N were monitored before
and during exposure to ambient and elevated ozone.
Materials and methods
Tree selection and maintenance
Naturally regenerated saplings of red spruce were selected in
September 1985 at a site located approximately 16 km west of
Mount Katahdin, Maine, that had been clear-cut in 1977. Soils
at the site were Typic Haplorthods derived from glacial till.
Selected trees were 1.0 to 1.5 m in height, relatively uniform
in architecture without extensive branching induced by animal
browsing, open-grown and not suppressed by adjacent trees,

and could be removed without undue damage to roots. The
selected trees were root-pruned by shovel approximately 0.5 m
from the stem in September 1985. Root pruning was intended
to stimulate regrowth of roots into the soil to be lifted so that
transplant shock would be reduced.
In May 1986, native soil from the B horizon at the site was
used to fill 360-l pots to within 25--30 cm of the lip of the pot.
Trees with the O and E soil horizons intact were removed from
the ground with shovels at the root pruning line. Each tree was
placed in a pot and, if necessary, additional soil surface material was used to fill the pot to the rim. The trees were transported to Ithaca, New York, and were maintained under 50%
shade cloth (black polypropylene) until July 25, 1986. After
that date they were unshaded. At the end of the 1986 growing
season, the pots were partially buried in the ground and
mulched with bark to the rim. The trees were watered as
needed during the growing seasons of 1987, 1988, 1989 and
1990. On July 3, 1991, all trees were sprayed with Bifenthrin
(0.6 g l −1 of wettable powder, FMC Corp., Philadelphia, PA) to

control spider mites. All trees were infrequently sampled for
carbohydrates and nutrients from August 1987 through October 1990 and routinely through September 1991.

Foliar N, degree of bud swelling and fertilization
Foliage was sampled for nutrient analyses on October 30, 1990
and May 16, July 17 and September 27, 1991. On each sample
date, foliage was cut, immediately wrapped in aluminum foil,
frozen in liquid nitrogen, freeze-dried, ground to pass a 40mesh screen, and subsequently analyzed for N by the microKjeldahl technique by staff of the Department of Pomology at
Cornell University (Grubinger et al. 1983).
On May 26, 1991, each tree was visually assessed for degree
of bud swelling. The following four categories were used: no
swelling, some swelling, most buds very swollen, and greater
than 10 % of buds with needles beyond the bud scales (breaking).
Before 1990, the trees were not fertilized. In August 1990,
13 of the 18 trees were fertilized with N,P,K (Peters, 15-16-17)
to deliver 4 g of N per tree. Foliar N content of current-year
foliage sampled in October 1990 was used to select six trees
for each of the following groups: low (0.59--0.82%), intermediate (0.87--1.03%), and high (1.04--1.22%). To assure adequate N for development of 1991 foliage, all trees were
fertilized on April 12, 1991 with 13.3 g Peters N,P,K (15-1617) to provide 2, 2.1 and 2.3 g as N, P and K, respectively. Trees
in the low-, intermediate- and high-N groups received 1, 2 and
4 g, respectively, of additional N as ammonium nitrate. On July
5, 1991, all trees were fertilized with 4.5 g Peters N,P,K
(15-16-17) with intermediate- and high-N groups receiving an

additional 2 and 5 g N, respectively, as ammonium nitrate.
Ozone exposures
Ozone (produced from bottled oxygen) was added to three of
the six nonfiltered (NF) open-top chambers (Kohut et al. 1987)
daily from May 20, 1991 until September 27, 1991. The ozone
treatments consisted of three chambers receiving NF air and
three chambers receiving NF air with ozone added to produce
twice ambient (2×) ozone concentrations from 1 h after sunrise
to 1 h before sunset. During the experiment, ozone monitors
were checked periodically against a transfer standard to assure
the accuracy of the measurements.
Additionally, loss of ozone in the Teflon sampling lines was
determined three times during the experiment and monitoring
data were adjusted accordingly.
Tree watering
Weights of individual tree--soil--pot systems were monitored
routinely during the experiment with weighing lysimeters
(Lauver et al. 1990). Deviations in weight from field capacity
were used to determine when to water the trees. Field capacities of the pot systems were determined by flooding each pot
and then recording the weights when water ceased to drain

from the pot (generally the next morning). The trees were not
watered from August 20 to September 3 to accelerate the
normal decline in foliar starch content (Woodbury et al. 1992)
and to determine plant available water in each pot system.

FOLIAR N, OZONE AND CARBOHYDRATE RESERVES IN RED SPRUCE

During the period when water was withheld, predawn and
midmorning branch water potentials were routinely monitored
on 1991 stems with a Scholander-type pressure chamber
(Model B, Soil Moisture Equipment Inc., Santa Barbara, CA).
Trees were rewatered when mean predawn water potentials
declined below −2.0 MPa.

169

and carbohydrates were tested by regression analyses (Minitab
Inc, Boston, MA).

Results

Ozone exposure

Needle and shoot morphology
Lengths and weights of shoots and weights and projected areas
of needles were determined on 1991 branches on several dates
after needle and branch growth had stopped. Projected needle
areas were determined with an image analyzer (AgVision
System, Decagon Devices, Pullman, WA, USA) after they
were removed from stems by rapid immersion in liquid N.
Carbohydrates
Carbohydrates were determined by cutting four to six shoots
with 1990 or 1991 needles between 1100 and 1130 h Eastern
Daylight Time and preparing the tissue by the same protocol
as described for N determination. Total soluble sugars were
extracted from ground tissue with 12/5/3 methanol/chloroform/water (v/v/v) (Haissig and Dickson 1979). Sugar concentration of the methanol--water phase of the extract was
measured by the anthrone reaction (Yemm and Willis 1954).
The starch or insoluble fractions were suspended in 4 ml of
0.10 M acetate--0.02 M NaF buffer, pH 4.5, placed in a boiling
water bath for 15 min and then cooled. One ml of buffer
containing 15 units of amyloglucosidase (EC 3.2.1.3) was

added to the residue, and the mixture incubated at 50 °C for
24 h. Glucose was determined by the glucose oxidase system
(Haissig and Dickson 1979, Ou-Lee and Setter 1985).
Experimental design and data analysis
Two ozone treatments, nonfiltered air (NF) and twice ambient
(2×), constituted the main plots. Ozone treatments were randomly assigned to six open-top chambers; thus, ozone effects
were tested over the replicate chambers (i.e., chambers nested
within ozone regimes). The 18 experimental trees were divided
into low-, intermediate- and high-N groups with six individuals per group. Three trees, one from each N group, were
randomly assigned to each chamber. Foliar N concentrations
were not discrete and so could not be incorporated into the
design as a second factor; instead N was included as a covariate
where appropriate and tested by SAS GLM (SAS Institute Inc.,
Cary, NC). Sugar and starch concentrations (analyzed separately at each date) were tested for a response to ozone by
one-way ANOVA, whereas the relationships between foliar N

Ozone exposures were conducted from 1 h after sunrise to 1 h
before sunset from May 20 until September 27, 1991. Seasonal
12-h-mean ozone concentrations (0800 to 2000 h) for NF and
2× treatments were 0.045 and 0.088 µl l −1, and maximum 1-h
averages for both were 0.112 and 0.241 µl l −1, respectively
(Table 1). Visible symptoms normally associated with ozone
injury were not detected on trees in either ozone treatment.
Influence of foliar N on foliar carbohydrates and date of bud
break
Foliar N concentrations of 1990 foliage ranged from 0.59 to
1.22% on October 30, 1990 and generally declined from October 1990 to September 1991 (Table 2). Nitrogen concentrations of 1991 foliage varied little from July to September 1991
and were similar within age class and N treatment in trees
exposed to the NF and 2× treatments (Table 2).
Soluble sugar and starch concentrations of 1990 stems and
starch concentrations of 1990 needles sampled on April 30,
1991 were positively correlated with N concentrations of 1990
foliage sampled on May 16, 1991 (Table 3), whereas soluble
sugar concentrations of 1990 foliage were positively, but
poorly, correlated with N concentrations of 1990 foliage (Table 3). Between April 30 and May 16, foliar starch concentrations increased in all trees, whereas sugar concentrations
declined marginally. On May 16, starch concentrations of 1990
foliage ranged from 175 to 272 mg gDW−1 and were not correlated with foliar N concentrations. In contrast, sugar concentrations declined in all trees over the same period (1 to 24 mg
gDW−1 and were more positively correlated with foliar N concentrations on May 16 than on April 30 (r = 0.74 versus 0.37,
Table 3). On May 26, buds on five of six trees in the low-N
group had not begun to swell, whereas buds on trees with
higher foliar N were swelling or breaking. Trees in the low-N
group had a significantly lower degree of bud swelling than
trees in the two higher N groups (Table 2, P = 0.001).
Influence of foliar N and ozone on carbohydrates and shoot
and needle growth
Sugar and starch concentrations were similar in trees exposed
to either NF or 2× ozone treatments regardless of date (Ta-

Table 1. Ozone exposure statistics for 12-h interval from 0800 to 2000 h EDT between May 20 and September 27, 1991.

TreatmentOzone concentration (µl l −1)
12-h Average24-h AverageMax 1-hTotal hours
DayNight> 0.08 µl l −1> 0.12 µl l −1

170

AMUNDSON, KOHUT AND LAURENCE

Table 2. Foliar N concentration of the low-, intermediate- and high-N groups within the NF and 2× ozone treatments. Values are means with SDs
in parentheses. Degrees of bud swelling on May 26, 1991 were as follows: 1 = no swelling, 2 = little swelling, 3 = very swollen, and 4 = breaking.

TreatmentN ContentBud swellingNitrogen (% DW)
1990 Foliage1991 Foliage

Oct 90May 91Sept 91July 91Sept 91
NFLow1.670.660.660.640.700.68
(1.2)(0.09)(0.11)(0.13)(0.13)(0.11)
Intermediate30.880.710.690.780.81
(1)(0.01)(0.08)(0.02)(0.04)(0.09)
High31.100.990.981.111.12
(1)(0.05)(0.05)(0.08)(0.13)(0.13)
2×Low10.820.750.690.700.73
(0)(0.00)(0.06)(0.09)(0.05)(0.07)

Table 3. Relationships between foliar N concentration (N, %) and stem or foliar sugar or starch concentration before, during and after shoot growth.
Relationships with P-values less than 0.05 are indicated with an asterisk (*).

DateTissueAgeEquationrP-value
Pre-bud break
April 30Stem90Starch = 31.6 + 20.5 N0.680.036*
Sugar = 25.0 + 16.6 N0.660.048*
Needle90Starch = 78.0 + 66.3 N0.650.028*
Sugar = 74.6 + 7.9 N0.370.382
May 16Needle90Starch = 201 + 8.3 N0.140.840
Sugar = 55 + 19.4 N0.740.005*
Shoot growth period
July 17Needle91Starch = 410 − 710 N + 323 N20.840.001*
Sugar = 66.8 + 17.2 N0.460.198
Needle90Starch = 41.2 − 11 N − 16.1 N20.630.117
Sugar = 81.1 + 10.3 N0.430.243
Cold hardening period
September 27Needle91Starch = 20.2 − 7.5 N0.410.308
Sugar = 127 + 1.7 N0.130.880

ble 4). Starch concentrations of 1991 foliage were negatively
correlated with foliar N concentrations on July 17 (r = 0.84,
Table 3). In contrast, sugar concentrations of 1991 foliage on
the same date were positively, but poorly, correlated with foliar
N concentrations (r = 0.46, Table 3). Similar trends were noted
in 1990 foliage (Table 3). These relationships were not altered
by exposure to ozone. By September 27, 1991, neither sugar
nor starch concentration of 1991 foliage was correlated with
foliar N concentration or prior ozone exposure.
Foliar starch concentrations of current-year foliage were
lower on August 20, 1991 compared to current-year foliage on
the same trees measured on August 16, 1989 (Table 4, P =
0.001). In contrast, mean sugar concentrations of current-year
foliage on August 16, 1989 were similar to those of currentyear foliage monitored on August 20, 1992 (Table 4).

Lengths of 1991 shoots increased with increasing N concentrations in trees exposed to NF or 2× ozone (Figure 1). Mean
lengths of 1991 shoots of trees exposed to 2× ozone sampled
from August 20 to September 27 tended to be longer than those
of NF-treated trees (4.67 versus 4.30 cm, P = 0.095). Mean
projected leaf area to dry weight ratio (specific leaf area) of
1991 foliage was positively correlated with mean foliar N
concentration (Figure 2). Ozone did not affect specific leaf
area of 1991 foliage (2× = 29.8 versus 28.6 cm2 g −1 for NF, P
= 0.47).
Exposure to ozone did not significantly affect predawn
branch water potentials of trees that were not watered for 2
weeks from August 20 to September 3 (August 20, NF = −1.31
± 0.25 MPa, 2× = −1.58 ± 0.12 MPa, P = 0.35; September 3,
NF = −2.13 ± 0.25 MPa, 2× = −2.50 ± 0.25 MPa, P = 0.22).

FOLIAR N, OZONE AND CARBOHYDRATE RESERVES IN RED SPRUCE

171

Table 4. Soluble sugar and starch concentrations of current-year foliage of red spruce saplings exposed to NF or 2× ozone before, during and after
a period of water stress. The SEs are presented in parentheses. Trees were maintained under ambient ozone conditions until May 20, 1991.
Comparisons between sugar and starch concentrations of current-year foliage measured on August 16, 1989 and August 20, 1991 for trees exposed
to NF or 2× treatments in 1991 were as follows: P-values for sugar concentrations, 1989 versus 1991, NF = 0.563, 2× = 0.241; P-values for starch
concentrations, 1989 versus 1991, NF = sink), (2) when shoot, cambium or root growth is vigorous (source = sink), and (3) when
tolerance to cold is established and maintained (source ≤ sink).
Pre-bud break period
In mid to late March in Ithaca, NY, photosynthetic capacity of
red spruce foliage increases rapidly from a midwinter low
(R.G. Amundson, unpublished data). Also, chloroplasts shorten, unclump and move toward the plasmalemma (Fincher and
Alscher 1992), whereas chlorophyll concentrations increase
and carotenoid concentrations decrease (Amundson et al.
1991). The substantial photosynthetic capacity of red spruce
up to 2 months before bud break results in large increases in
carbohydrate storage in stems and foliage before bud break.
The positive correlation between stem and needle carbohydrates and foliar N during late April indicates that stem and
needle carbohydrate storage pools of N-deficient trees are
filled later than those of trees with higher foliar N concentrations. The delay in bud break of N-deficient trees and positive
relationships between stem and needle carbohydrates and foliar N before bud break suggest that date of bud break is either
directly influenced by foliar N concentrations or delayed in
N-deficient trees by inadequate carbohydrate reserves to expand new foliage.
Active growth period
During the period of rapid shoot elongation, new foliage
changes from importing to exporting carbon (Turgeon 1989)
and thus ends its reliance on reserves from other tissues resulting in a negative relationship between foliar N and foliar starch
concentrations. Negative relationships between foliar N and
starch have also been reported for Scots pine (Pinus sylvestris
L.) (Ericsson 1979), willow (Salix aquatica Smith) (Waring et
al. 1985) and sedge (Eriophorum vaginatum L.) (Chapin et al.
1986). Chapin (1991) suggests that starch accumulates in
leaves of N-limited plants because there is sufficient N for
continued carbon fixation but insufficient N to maintain normal growth (sink strength declines). Reduced length of 1991
shoots and higher starch concentrations of 1991 foliage in the
N-deficient trees supports that hypothesis.
In mid-August, starch concentrations were significantly
lower than in the same trees in 1989 (Amundson et al. 1993)
or in a similar group of trees in 1990 (Woodbury et al. 1992).
The reduction probably resulted from fertilization in April and
July (cf. Ericsson 1979, Waring et al. 1985, Chapin et al. 1986),
most likely because the carbon that would be stored as starch
was allocated to root growth. Allocation of carbon is controlled
by source and sink strengths that vary with time, growth form
and potential rate of growth (see Laurence et al. 1994, Pell et
al. 1994). Thus, fertilization does not always reduce foliar
carbohydrate reserves. We assume that foliar reserves were
diverted to root growth by mid-August to increase nutrient
acquisition, whereas soil temperatures were too low in late
April--early May for root growth. Without a sink for the newly
fixed photosynthate, starch reserves accumulated in twigs and
foliage before bud break.

Cold hardening period
The loss of starch and increase in sugars by September 27
indicated that the trees were cold hardening (Parker 1959,
Senser et al. 1971, Alscher et al. 1989). By then neither starch
nor sugar concentration of current-year foliage was correlated
with foliar N.
As expected, N deficiency had multiple effects on the
growth capacity of red spruce. Foliar N concentrations are
positively correlated with photosynthetic capacity in red
spruce (Amundson et al. 1992) which may explain the delay in
filling of foliar starch pools in late April. Furthermore, N
deficiency reduced carbon fixation capacity of current-year
foliage by delaying the date of bud break and by reducing
shoot lengths and specific needle areas.
Effects of ozone on foliar carbohydrate reserves and growth
Although we anticipated that N deficiency would raise foliar
starch concentrations and thus predispose the trees to ozoneinduced reductions in starch, it did not. Fertilization of the
trees most likely resulted in reduced foliar starch concentrations during mid-August. Our data support the results of earlier
studies where short-term exposure to ozone had minimal effects on red spruce seedlings (Taylor et al. 1986, Alscher et al.
1989, Laurence et al. 1989). Although exposure to ozone for
one growing season depressed foliar starch concentrations in
shortleaf pine (Pinus echinata Mill.) (Paynter et al. 1991) and
loblolly pine (Pinus taeda L.) (Meier et al. 1990), longer
exposures were needed to reduce foliar starch concentrations
in red spruce seedlings (Amundson et al. 1991) and saplings
(Woodbury et al. 1992) that were not N limited.
Red spruce response to multiple stresses
Because N deficiency and ozone stress have opposite effects
on foliar starch reserves, we postulated that the two stresses
would have an interactive effect on foliar starch concentrations. Pell et al. (1990) found such interactions in a study of
radish. However, no interactions between ozone exposure and
foliar N concentrations were detected; the relatively low starch
concentrations and short duration of the ozone exposure may
have millitated against such an interaction.
Although N deficiency decreased shoot length and ozone
tended to increase shoot length, it is unclear whether these two
stresses would interact to change shoot length in the long term.
Clearly, changes in shoot length would affect tree stature and
thus light capture, carbon fixation and growth.
Several factors influence the response of red spruce to stress.
The species is characterized by inherently low rates of gas
exchange and low rates of water loss during water stress (Seiler
and Cazell 1990) that predispose it to avoidance of stress from
short-term ozone or water stress. Furthermore, it maintains
large foliar reserves of carbon. Although foliar starch reserves
of red spruce are reduced during water stress (Amundson et al.
1993) or prolonged exposure to ozone (Woodbury et al. 1992),
these stresses did not produce accelerated senescence of older
tissues, a symptom normally associated with such stresses in
faster growing species (Pell et al. 1994). The increase in foliar
sugar concentrations at the same time that foliar starch concen-

FOLIAR N, OZONE AND CARBOHYDRATE RESERVES IN RED SPRUCE

trations declined during water stress (Amundson et al. 1993)
suggest that starch reserves were used at that time to maintain
cell integrity. Additionally, Hauslauden et al. (1990) found that
foliar carbohydrate reserves may be diverted to the synthesis
of antioxidant compounds in response to exposure to ozone,
further reducing susceptibility to long-term exposures. The
changing relationships between foliar N and starch and sugar
concentrations as source and sink strengths changed suggest
that these foliar reserves are mobilized in response to changing
sink strengths, which vary with severity of the stress and the
organ sensing that stress. Collectively the above factors result
in the relative insensitivity of red spruce to short-term stress.
Acknowledgments
This research was supported by funds provided by the Electric Power
Research Institute under contract RP2799-1, the Empire State Electric
Energy Research Corporation, the Niagara Mohawk Power Corporation, and the United States Forest Service. This paper has not been
subject to Forest Service peer review and should not be construed to
represent the policies of the Agency. We thank Horacio Buscaglia,
Suzanne Fellows, Terry Lauver, Richard Raba and Paul Van Leuken
for invaluable operational and technical support.
References
Adams, M.B., H.L. Allen and C.B. Davey. 1986. Accumulation of
starch in roots and foliage of loblolly pine (Pinus taeda L.): effects
of season, site and fertilization. Tree Physiol. 2:35--46.
Alscher, R.G., R.G. Amundson, J.R. Cumming, S. Fellows, J. Fincher,
G. Rubin, P. van Leuken and L.H. Weinstein. 1989. Seasonal
changes in the pigments, carbohydrates and growth of red spruce as
affected by ozone. New Phytol. 113:211--223.
Amundson, R.G., R.G. Alscher, S. Fellows, G. Rubin, J. Fincher,
P. van Leuken and L.H. Weinstein. 1991. Seasonal changes in the
pigments, carbohydrates, and growth of red spruce as affected by
exposure to ozone for two growing seasons. New Phytol. 118:125-137.
Amundson, R.G., J.L. Hadley, J. Fincher, S. Fellows and R.G. Alscher.
1992. Comparisons of seasonal changes in photosynthetic capacity,
pigments, and carbohydrates of healthy sapling and mature red
spruce and of declining and healthy red spruce. Can. J. For. Res.
22:1605--1616.
Amundson, R.G., R.J. Kohut, J.A. Laurence, S. Fellows and L. Colavito. 1993. Red spruce reversibly allocates starch to sugars in
foliage during moderate water stress. Environ. Exp. Bot. 33:383-390.
Chapin III, F.S. 1991. Integrated responses of plants to stress. BioScience 41:29--36.
Chapin III, F.S., G.R. Shaver and R.A. Kedrowski. 1986. Environmental controls over carbon, nitrogen, and phosphorus fractions in
Eriophorum vaginatum in Alaska tussock tundra. J. Ecol. 74:167-195.
Chapin III, F.S., E.-D. Schulze and H.A. Mooney. 1990. The ecology
and economics of storage in plants. Annu. Rev. Ecol. Syst. 21:423-447.
Ericsson, A. 1979. Effects of fertilization and irrigation on the seasonal changes of carbohydrate reserves in different age-classes of
needle on 20-year-old Scots pine trees (Pinus sylvestris). Physiol.
Plant. 45:423--429.
Fernandez, I.J. and R.A. Struchtemeyer. 1990. Correlation between
element concentrations in spruce foliage and forest soils. Commun.
Soil Sci. Plant Anal. 15:1243--1255.

173

Fincher, J. and R.G. Alscher. 1992. The effects of long-term ozone
exposure on injury in seedlings of red spruce (Picea rubens Sarg.).
New Phytol. 120:49--59.
Friedland, A.J., G.J. Hawley and R.A. Gregory. 1988. Red spruce
foliar chemistry in northern Vermont and New York. Plant Soil
105:189--193.
Grime, A.D.M. 1977. Evidence for the existence of three primary
strategies in plants and its relevance to ecological and evolutionary
theory. Am. Nat. 111:1169--1194.
Grubinger, B.P., P.L. Minotti, H.C. Wein and A.D. Turner. 1983.
Tomato response to starter fertilizer, polyethylene mulch and level
of soil phosphorus. J. Am. Soc. Hortic. Sci. 118:212--216.
Haissig, B.E. and R.E. Dickson. 1979. Starch measurement in plant
tissue using enzymatic hydrolysis. Physiol. Plant. 47:151--157.
Hauslauden, A., N.R. Madamanchi, S. Fellows, R.G. Alscher and R.G.
Amundson. 1990. Seasonal changes in antioxidants in red spruce as
affected by ozone. New Phytol. 115:447--458.
Kohut, R.J., R.G. Amundson and J.A. Laurence. 1987. Evaluation of
the effects of ozone and acidic precipitation, alone and in combination, on the photosynthesis, nutrition, and growth of red spruce and
sugar maple. In Acid Rain: Scientific and Technical Advances. Eds.
R. Perry, R.M. Harrison, J.N.B. Bell and J.N. Lester. Selper Ltd.,
London, pp 588--595.
Kramer, P.J. and T.T. Kozlowski. 1979. Physiology of woody plants.
Academic Press Inc., Orlando, FL, 811 p.
Laurence, J.A., R.J. Kohut and R.G. Amundson. 1989. Response of
red spruce seedlings exposed to ozone and simulated acidic precipitation in the field. Arch. Environ. Contam. Toxicol. 18:285--290.
Laurence, J.A., R.G. Amundson, A.L. Friend, E.J. Pell and P.J. Temple. 1994. Allocation of carbon in plants under stress: an analysis of
the ROPIS experiments. J. Environ. Qual. 23:412--417.
Lauver, T., R.H. Mandl, R.J. Kohut and J.A. Laurence. 1990. A
weighing lysimeter for determining water loss in red spruce saplings (Picea rubens Sarg.). Environ. Exp. Bot. 30:157--164.
Little, C.H.A. 1970. Seasonal changes in carbohydrate and moisture
content in needles of balsam fir (Abies balsamea). Can. J. Bot.
48:2021--2028.
McLaughlin, S.B. 1985. Effects of air pollution on forests: a critical
review. J.A.P.C.A. 14:512--534.
McLaughlin, S.B., C.P. Andersen, N.T. Edwards, W.K. Roy and P.A.
Layton. 1990. Seasonal patterns of photosynthesis and respiration
of red spruce saplings from two elevations in declining southern
Appalachian stands. Can. J. For. Res. 20:485--495.
McLaughlin, S.B., C.P. Andersen, P.J. Hanson, M.G. Tjoelker and
W.K. Roy. 1991. Increased dark respiration and calcium deficiency
of red spruce in relation to acidic deposition at high-elevation
southern Appalachian Mountain sites. Can. J. For. Res. 21:1234-1244.
Meier, S., L.F. Grand, M.M. Schoeneberger, R.A. Reinert and R.I.
Bruck. 1990. Growth, ectomycorrhizae and nonstructural carbohydrates of loblolly pine seedlings exposed to ozone and soil water
deficit. Environ. Pollut. 64:11--17.
Moore, P.D. 1984. Why be an evergreen? Nature 312:703.
Ou-Lee, T-M. and T.L. Setter. 1985. Enzyme activities of starch and
sucrose pathways and growth of apical and basal maize kernels.
Plant Physiol. 79:848--851.
Parker, J. 1959. Seasonal variations in sugars of conifers with some
observations on cold resistance. For. Sci. 5:56--63.
Paynter, V.A., J.C. Reardon and V.B. Shelburne. 1991. Carbohydrate
changes in shortleaf pine (Pinus echinata) needles exposed to acid
rain and ozone. Can. J. For. Res. 21:666--671.

174

AMUNDSON, KOHUT AND LAURENCE

Pell, E.J., W.E. Winner, C. Vinten-Johansen and H.A. Mooney. 1990.
Response of radish to multiple stresses. I. Physiological and growth
responses to changes in ozone and nitrogen. New Phytol. 115:439-446.
Pell, E.J., P.J. Temple, A.L. Friend, H.A. Mooney and W.E. Winner.
1994. Compensation as a plant response to ozone and associated
stresses: an analysis of ROPIS experiments. J. Environ. Qual.
23:429--436.
Rundel, P.W. and D.J. Parsons. 1980. Nutrient changes in two chaparrel shrubs along a fire-induced age gradient. Am. J. Bot. 67:51--58.
Seiler, J.R. and B.H. Cazell. 1990. Influence of water stress on the
physiology and growth of red spruce seedlings. Tree Physiol. 6:69-77.
Senser, M., P. Dittrich, O. Kandler, A. Thanbichler and B. Kuhn. 1971.
Isopenstudien über den Einfluss der Jahreszeit auf den Oligosaccharidumsatz bein Coniferen. Ber. Deutsch. Bot. Gesellschaft
84:445--455.
Taylor, G.E., R.J. Norby, S.B. McLaughlin, A.H. Johnson and R.S.
Turner. 1986. Carbon dioxide assimilation and growth of red spruce
(Picea rubens Sarg.) seedlings in response to ozone, precipitation
chemistry, and soil type. Oecologia 70:163--171.

Thompson, W.A., P.E. Kriedemann and I.E. Craig. 1992. Photosynthetic response to light and nutrients in sun-tolerant and shade-tolerant rainforest trees. I. Growth, leaf anatomy and nutrient content.
Aust. J. Plant Physiol. 19:1--18.
Turgeon, R. 1989. The sink--source transition in leaves. Annu. Rev.
Plant. Physiol. 40:119--138.
Vitousek, P.M. 1982. Nutrient cycling and nutrient use efficiency. Am.
Nat. 119:553--572.
Waring, R.H., A.J.S. McDonald, S. Larsson, T. Ericsson, A. Wiren,
E. Arwidsson, A. Ericsson and T. Lohammar. 1985. differences in
chemical composition of plants grown at constant relative growth
rates with stable mineral nutrition. Oecologia 66:157--160.
Woodbury, P.B., R.G. Amundson, R.J. Kohut and J.A. Laurence. 1992.
Stomatal conductance, whole-tree water use, and foliar carbohydrate status of red spruce saplings exposed to ozone, acid precipitation, and drought. In Transactions of the 1991 Air and Waste
Management Association International Symposium on Tropospheric Ozone and the Environment II. Ed. R. Berglund. Air and
Waste Management Association, Pittsburgh, PA, pp 618--628.
Yemm, E.W. and A.J. Willis. 1954. The estimation of carbohydrates in
plant extracts by anthrone. Biochem. J. 57:508--514.