Directory UMM :Data Elmu:jurnal:T:Tree Physiology:Vol15.1995:
Tree Physiology 15, 577--584
© 1995 Heron Publishing----Victoria, Canada
The influence of magnesium deficiency on carbohydrate
concentrations in Norway spruce ( Picea abies) needles
BEATE MEHNE-JAKOBS
Institut für Forstbotanik und Baumphysiologie, Albert-Ludwigs-Universität, Bertoldstrass
e 17, D-79085 Freiburg, Germany
Received April 5, 1994
Summary Both short- and long-term effects of Mg deficiency on carbohydrate metabolism were investigated in
6-year-old clonal Norway spruce (Picea abies (L.) Karst.) trees
cultivated in sand culture with an optimal supply of nutrients,
except for Mg which was supplied at 0.203, 0.041 and
0.005 mM to provide optimal, moderately deficient and severely deficient Mg supply, respectively. Annual changes in
carbohydrate concentrations (starch, sucrose, glucose and fructose) were analyzed and diurnal changes were investigated on
a single day during the summer.
Older needles of trees in the moderate Mg-deficiency treatment developed tip-yellowing symptoms, whereas currentyear needles remained green. The severe Mg-deficiency
treatment led to pronounced yellowing symptoms in needles of
all ages. Increased carbohydrate concentrations were observed
before needle yellowing occurred. Diurnal and annual changes
in carbohydrates were similar in all treatments; however, carbohydrate concentrations were influenced by Mg supply. In
both Mg-deficiency treatments, starch concentrations increased in needles, especially during summer and autumn.
Starch accumulation was more pronounced at the beginning of
the Mg-deficiency treatments than at the end of the treatments.
Sucrose, and to a minor extent, glucose and fructose concentrations tended to increase in response to Mg deficiency. The
consequences of Mg deficiency on carbohydrate metabolism
are discussed with respect to reduced plant growth and decreased transport rates of carbohydrates to sink organs.
late autumn (Hampp et al. 1987, Einig and Hampp 1990).
Because interactions with environmental factors, such as
drought, acid deposition and air pollutants (e.g., Vogels et al.
1986, Landoldt and Krause-Lüthy 1989, Hampp 1992), may
alter the carbohydrate pools, the effects of Mg deficiency on
carbohydrate metabolism need to be studied under controlled
conditions.
A deficiency in Mg nutrition can affect carbon metabolism
in many ways causing reductions as well as accumulations of
specific carbohydrates. Because Mg is a constituent of the
chlorophyll molecule and is also a cofactor of a series of
enzymes involved in carbon fixation, it is essential for photosynthesis (Laing and Christeller 1976, Lorimer et al. 1976).
Magnesium is also required for ATP metabolism and is, therefore, essential for many metabolic processes, including carbohydrate metabolism and the synthesis of proteins, fats and
nucleic acids. It is also a key element in membrane transport
(Marschner 1986).
The main objective of this study was to test the hypothesis
that Mg deficiency results in the accumulation of carbohydrates in Norway spruce needles. We investigated short-term
and long-term effects of Mg deficiency on starch, sucrose,
glucose and fructose concentrations in needles, and we also
evaluated diurnal and annual changes in carbohydrates with
respect to Mg nutrition and needle age.
Keywords: carbohydrate metabolism, fructose, glucose,
growth, starch accumulation, sucrose.
Materials and methods
Plant material and study design
Introduction
There is evidence that, in Norway spruce (Picea abies (L.)
Karst.) needles from stands showing forest decline symptoms,
changes in pool sizes of carbohydrates are caused by Mg
deficiency. Accumulations of starch in yellowing needles of
declining Norway spruce trees have been observed by Fink
(1983), Oren et al. (1988) and Forschner et al. (1989); however,
Hampp and colleagues did not find any changes in starch
concentrations, perhaps as a result of the interactive effects of
other stress factors, although they did observe a longer retention of starch in yellowing needles than in green needles during
Two experiments, one long term (Experiment 1) and one short
term (Experiment 2), were conducted during the growing seasons of 1990 and 1991, respectively. In Experiment 1, 100
six-year-old Norway spruce trees of Clone 1382/113 (provenance Rothenkirchen 84011, Frankenwald, Germany) were
planted in an outdoor facility in spring 1988. In Experiment 2,
100 five-year-old Norway spruce trees of Clone 1213/113 of
the same provenance were planted in October 1990. In both
experiments, the nonmycorrhizal trees were cultivated in sand
culture in 70-liter pots and individually supplied with nutrients
by means of a continuously circulating solution, which was
replaced once a week. The nutrient solutions were adjusted to
achieve optimum growth according to the principles set out by
578
MEHNE-JAKOBS
Ingestad (1959, 1979). One liter of nutrient solution contained:
50 mg KNO3, 68 mg KH2PO4, 65 mg Ca(NO3)2⋅4H2O, 11.5 mg
(NH4)2HPO4, 90 mg NH4NO3, 50 mg MgSO4⋅7H2O, 5 mg
Fe-EDTA, 800 µg MnSO4⋅4H2O, 80 µg CuSO4⋅5H2O, 200 µg
ZnSO4⋅7H2O, 600 µg H3BO3, 17.5 µg Na2MoO4⋅1H2O plus
magnesium as specified. Magnesium was added to the nutrient
solutions to provide concentrations of 0.203 (optimal, Treatment 1), 0.041 (moderately deficient, Treatment 2) and 0.005
mM (severely deficient, Treatment 3). Sulfate in the Mg-deficiency treatments was supplied as Na2SO4⋅10H2O in concentrations corresponding to the deficiency treatments.
1 h (Dekker and Richards 1971). To remove free glucose, the
extract was incubated at 95 °C for 3 min, adjusted to pH 4.6
with 0.5 M acetic acid, and then centrifuged at 10,000 g for
5 min (Einig and Hampp 1990). Aliquots of 20 to 60 µl of the
supernatant were used for the enzymatic determination of
starch according to Outlaw and Manchester (1979).
Chlorophyll concentrations were determined after extraction in 80% acetone (Ziegler and Egle 1965), and calculated
according to Lichtenthaler (1987). Magnesium concentrations
of needles were analyzed by the AAS--AES flame technique
(Perkin Elmer 4000, Ueberlingen, Germany) after dry ashing
and digestion with HNO3-HCl.
Sampling conditions
In Experiment 1, current-year to 2-year-old needles were taken
from the fourth whorl between 0800 and 0930 h MET (MidEuropean Time) in May, June, August and October 1990, and
in March 1991 for carbohydrate analysis. In Experiment 2,
needles were taken from current-year and 1-year-old twigs of
the third whorl in July, August and September 1991 for carbohydrate analysis. Samples were collected between 1100 and
1230 h MET at high irradiance (> 1200 µmol m −2 s −1) after a
period of at least 2 days with bright sunshine. In both experiments, samples were taken from six trees per Mg treatment,
and all samples were taken from the sun-exposed, upper side
of the twigs. For the study of diurnal changes in carbohydrates,
needles from trees in the optimal-Mg treatment and the severe
Mg-deficiency treatment were sampled from current-year and
1-year-old shoots every 2 and 4 h, respectively, between 0400
and 2200 h MET on August 22, 1991, a day following a period
of high temperatures and high irradiance.
For the determination of Mg, needle samples were taken
from current-year to 2-year-old southerly exposed twigs of the
fourth whorl in October 1990 and 1991. Five samples of each
treatment and age class were combined to form one mixed
sample. Magnesium was assayed in two and five replicates of
the mixed samples in 1990 and 1991, respectively.
Temperature, relative humidity and solar irradiance, measured with a quantum sensor (Li-Cor Inc., Lincoln, NE), were
recorded at each sampling time.
The needle samples were immediately frozen in liquid nitrogen and stored at −80 °C. Frozen needle tissue was homogenized with a microdismembrator (Braun, Melsungen,
Germany), and the resulting powder was freeze-dried at
−25 °C and stored under vacuum at −20 °C.
Measurements
Concentrations of sucrose, glucose and fructose in the needles
were determined according to Einig and Hampp (1990). Two
mg of lyophilized needle homogenate was extracted in 1 ml of
65% (v/v) aqueous ethanol at 70 °C for 1 h. Activated charcoal
(2%, w/v) was used in order to reduce the blank reading. The
mixture was then centrifuged at 10,000 g for 5 min, and 20 to
200 µl aliquots of the supernatant were assayed according to
Jones and Outlaw (1981).
To determine needle starch concentrations, 2 to 6 mg
aliquots of needle homogenate were extracted with 0.5 ml of
0.5 M NaOH in Eppendorff vials at ambient temperature for
Statistical analysis
Means and standard errors (SE) were calculated separately for
each sampling time and each needle age class. Differences
among the treatments within each needle age class were evaluated by analysis of variance and Tukey’s test performed with
the SPSS-PC+ software package.
Results
After 3 years of adaptation to Mg deficiency, Mg concentrations in needles of Norway spruce trees closely paralleled the
nutrient regimes, with lowest values in the severe Mg-deficiency treatment (Table 1). Trees in the long-term moderate
Mg-deficiency treatment showed typical symptoms of Mg
deficiency, including tip-yellowing of the 1- and 2-year-old
needles. The current-year needles, which developed in May,
remained green throughout the growing season, and their chlorophyll concentrations did not differ from those of the controls
(Figure 1). In contrast, in the long-term, severe Mg-deficiency
treatment, needles of all age classes displayed pronounced
yellowing (Figure 1). The short-term Mg-deficiency treatments resulted in lower needle Mg concentrations than the
long-term Mg-deficiency treatments (Table 1). In the shortterm Mg-deficiency treatments, the first deficiency symptoms
became visible in July. One-year-old needles of trees in the
short-term, moderate Mg-deficiency treatment exhibited tipyellowing, whereas the current-year needles remained green
and had chlorophyll concentrations comparable to those of
Table 1. Magnesium concentrations (mg g DW−1) in current-year, and
1- and 2-year-old needles of Norway spruce trees subjected to longterm (Experiment 1, n = 2) or short-term (Experiment 2, n = 5)
Mg-deficiency treatments.
Needle age
Control
Moderate
deficiency
Severe
deficiency
Experiment 1
Current-year
One-year-old
Two-year-old
2.39
2.07
2.05
0.93
0.56
0.47
0.48
0.32
0.34
Experiment 2
Current-year
One-year-old
Two-year-old
1.33
1.07
1.20
0.59
0.46
0.46
0.24
0.33
0.28
CARBOHYDRATES IN MAGNESIUM-DEFICIENT NORWAY SPRUCE
579
Table 2. Chlorophyll concentrations (µg g FW−1) in current-year and
1-year-old needles of Norway spruce trees subjected to short-term
Mg-deficiency treatments (Experiment 2, means ± SE, n = 6). Significant differences between the treatments: ** = P < 0.01, *** = P <
0.001. Values followed by different letters differ significantly among
the treatments (Tukey’s test, P < 0.05).
Sampling
Figure 1. Chlorophyll concentrations in current-year, and 1- and 2year-old needles of Norway spruce trees adapted to Mg deficiency
(Experiment 1) (d controls, j moderate Mg deficiency, and . severe
Mg deficiency). Means of nine samples ± SE are presented for each
month (significant differences between treatments: * = P < 0.05, ** =
P < 0.01, and *** = P < 0.001).
control needles (Table 2). In the short-term, severe Mg-deficiency treatment, yellowing symptoms were most pronounced
among the current-year needles. Throughout the growing season, chlorophyll concentrations of needles in the short-term
severe Mg-deficiency treatment were significantly lower than
those of control needles (Table 2).
As a consequence of long-term Mg deficiency, starch concentrations increased in the current-year needles after their
maturation from August onward (Figure 2). In addition, the
Mg-deficiency treatments resulted in higher sucrose and fructose concentrations in the current-year needles in August 1990
and March 1991, respectively, than in the corresponding con-
Control
Moderate
deficiency
Severe
deficiency
Current-year needles
July
1730 ± 48 a
August
2013 ± 108 a
September
2020 ± 71 a
1731 ± 56 a
1777 ± 75 ab
1981 ± 52 a
1343 ± 117 b**
1347 ± 179 b**
1431 ± 140 b***
One-year-old needles
July
2334 ± 79 a
August
2463 ± 119 a
September
2662 ± 130 a
1859 ± 111 b
1537 ± 215 b
1870 ± 131 b
1702 ± 125 b**
1672 ± 188 b**
1471 ± 81 b***
trol needles. One-year-old Mg-deficient needles exhibited a
decrease in starch accumulation in May, when the development of new shoots started (Figure 3), and this was accompanied by increased concentrations of glucose and fructose in
May and June. Significant increases in sucrose concentrations
occurred in 1-year-old needles in the moderate- and severe
Mg-deficiency treatments in May and October, respectively.
As observed in current-year needles, the Mg-deficiency treatments caused increases in starch concentrations of 2-year-old
needles in August and October and increases in sucrose concentrations throughout the measuring period (Figure 4). The
well-known annual changes in starch, glucose and fructose
concentrations, which generally reflect growth and developmental processes in the trees, were observed in all treatments.
The accumulation of starch in the short-term Mg-deficiency
treatment was even more pronounced than in the long-term
experiment, especially in 1-year-old needles (Table 3). The
needles in the moderate Mg-deficiency treatment exhibited
peak concentrations of glucose and fructose in July. A significant increase in sucrose concentration also occurred in July in
both current-year and 1-year-old needles of the severe Mg-deficiency treatment and in 1-year-old needles of the moderate
Mg-deficiency treatment. However, in August, sucrose concentrations decreased in both needle age classes of the severe
Mg-deficiency treatment in parallel with large increases in
starch concentrations.
In August 1991, diurnal changes in carbohydrate concentrations were followed in samples from trees in the control and
severe Mg-deficiency treatments after a period of high temperatures and intensive irradiance. During daytime, the temperature reached 35 °C, and relative humidity declined to
about 20% (Figure 5). As a consequence of the hazy sky,
photosynthetically active radiation (PAR) was saturating for
photosynthesis for only a few hours around noon. Starch concentrations of the current-year control needles showed only
minor alterations during daytime, whereas starch concentrations in the severe Mg-deficiency treatment decreased
throughout the day (Figure 6). Although chlorophyll concentrations were reduced in current-year needles of the severe
580
MEHNE-JAKOBS
Figure 2. Starch, sucrose, glucose and fructose concentrations in
current-year needles of Norway spruce trees adapted to Mg deficiency
(Experiment 1) (d controls, j moderate Mg deficiency, and . severe
Mg deficiency). Means of six samples ± SE are presented for each
month (significant differences between treatments: * = P < 0.05, and
** = P < 0.01). Note the additional scale for the October data.
Mg-deficiency treatment, starch accumulation was five times
greater than that of the control needles. Sucrose concentrations
rose in the morning and then remained constant throughout the
day. Treatment-related increases in sucrose concentration were
only observed in the morning. In the evening, glucose and
fructose concentrations increased in the Mg-deficiency treatment. Short-term Mg deficiency also resulted in increased
starch concentrations in 1-year-old needles, but values varied
greatly (Figure 7).
Figure 3. Starch, sucrose, glucose and fructose concentrations in
1-year-old needles of Norway spruce trees adapted to Mg deficiency
(Experiment 1) (d controls, j moderate Mg deficiency, and . severe
Mg deficiency). Means of six samples ± SE are presented for each
month (significant differences between treatments: * = P < 0.05, ** =
P < 0.01, and *** = P < 0.001). Note the additional scale for the
October data.
Discussion
Symptoms of Mg deficiency in Norway spruce typically occur
as tip-yellowing in older needles, whereas the current-year
needles remain green (Baule and Fricker 1967, Zöttl 1985,
Bergmann 1988). A similar pattern of symptoms was observed
in trees in the short-term, moderate Mg-deficiency treatment;
however, even current-year needles developed severe chlorosis
in the short-term, severe Mg-deficiency treatment. As observed
in the field (Mies and Zöttl 1985, Lange et al. 1989), the
yellowing symptoms were more intense on the upper, sun-ex-
CARBOHYDRATES IN MAGNESIUM-DEFICIENT NORWAY SPRUCE
581
Table 3. Starch (nmol glycosyl units mg DW−1), sucrose, glucose and
fructose concentrations (nmol mg DW−1) in current-year and 1-year-old
needles of Norway spruce subjected to short-term Mg-deficiency
treatments (Experiment 2, means ± SE, n = 6; for further explanations,
see Table 2).
Sampling
Starch
Current-year
July
August
September
One-year-old
July
August
September
Sucrose
Current-year
July
August
One-year-old
July
August
Glucose
Current-year
July
August
One-year-old
July
August
Fructose
Current-year
July
August
One-year-old
July
August
Control
Moderate
deficiency
Severe
deficiency
133 ± 36
1.8 ± 0.2 a
7.0 ± 0.6
152 ± 51
3.6 ± 0.7 a
10.4 ± 2.3
128 ± 49
39.8 ± 9.2 b***
9.3 ± 1.4
43 ± 11 a
1.7 ± 0.2 a
9.8 ± 2.0 a
245 ± 99 b
11.6 ± 5.2 a
22.4 ± 4.2 b
108 ± 15 a***
61.1 ± 16.9 b**
19.2 ± 1.5 ab*
179 ± 4 a
152 ± 3 a
184 ± 2 a
167 ± 11 a
202 ± 5 b**
117 ± 3 b***
150 ± 7 a
120 ± 4 a
193 ± 6 b
132 ± 8 a
177 ± 4 b***
109 ± 1 b**
11 ± 0.4 a
8 ± 0.3
17 ± 1.7 b
7 ± 0.5
10 ± 0.8 a***
7 ± 0.9
6 ± 0.5 a
6 ± 0.3
10 ± 0.1 b
5 ± 0.4
6 ± 0.4 a**
6 ± 0.6
10 ± 0.8 ab
5 ± 0.3
13 ± 1.2 a
4 ± 0.4
7 ± 0.6 b**
4 ± 0.5
5 ± 0.3 a
3 ± 0.2
8 ± 0.8 b
3 ± 0.2
4 ± 0.3 a***
3 ± 0.4
Figure 4. Starch, sucrose, glucose and fructose concentrations in
2-year-old needles of Norway spruce trees adapted to Mg deficiency
(Experiment 1) (d controls, j moderate Mg deficiency, and . severe
Mg deficiency). Means of six samples ± SE are presented for each
month (significant differences between treatments: * = P < 0.05, ** =
P < 0.01, and *** = P < 0.001). Note the additional scale for the
October data.
posed sides of the needles than on the lower, shaded sides. This
pattern of deficiency symptoms continued throughout the 3year study and was not accompanied by tree mortality. Chlorophyll concentrations were reduced when the Mg
concentration of the needles was less than 0.5 mg g DW−1. This
value is between the threshold values of 0.7 mg g DW−1 reported
for Norway spruce seedlings (Ingestad 1962) and 0.3 mg
g DW−1 reported for older trees (Reemtsma 1986, Köstner 1989,
Schulze 1989). The differences in the threshold values might
be associated with tree age or with differences in nitrogen
nutrition (Ingestad 1979).
Figure 5. Diurnal course of temperature (d), relative humidity (j)
and light intensity (m) on August 22, 1991.
The observed diurnal and annual dynamics of carbohydrate
concentrations in the needles confirms earlier studies (Senser
et al. 1975, Ericsson 1979, Fink 1983, Forschner et al. 1989,
582
MEHNE-JAKOBS
Figure 6. Diurnal course of starch, sucrose, glucose and fructose
concentrations in current-year needles of Norway spruce trees under
short-term Mg-deficiency treatment (Experiment 2) (d controls, and
. severe Mg deficiency). Means of three samples ± SE are presented
for each month (significant differences between treatments: * = P <
0.05, and ** = P < 0.01).
Figure 7. Diurnal course of starch, sucrose, glucose and fructose
concentrations in 1-year-old needles of Norway spruce trees under
short-term Mg-deficiency treatment (Experiment 2) (d controls, and
. severe Mg deficiency). Means of three samples ± SE are presented
for each month (significant differences between treatments: * = P <
0.05, ** = P < 0.01, and *** = P < 0.001).
Einig and Hampp 1990, Einig et al. 1990, 1991). Similar
diurnal and annual fluctuations were observed in all treatments, but carbohydrate concentrations were influenced by the
Mg-deficiency treatments. Needles in both Mg-deficiency
treatments exhibited an increase in starch concentrations, especially during summer and autumn, and in the short-term
Mg-deficiency treatment. In addition, sucrose and, to a minor
extent, glucose and fructose concentrations increased in response to the Mg-deficiency treatments. Similar increases in
carbohydrates have been observed in leaves of Mg-deficient
herbaceous plants in association with decreases in the accumulation of assimilates in sink organs (Beringer and Forster 1981,
Fischer and Bussler 1988, Fischer and Bremer 1993). Fink
(1991) observed starch accumulation in the chloroplasts of
Norway spruce needles, suffering from experimentally induced Mg deficiency.
The accumulation of starch began before the reduction in
chlorophyll concentration occurred. Starch accumulation was
highest in needles exhibiting slight yellowing symptoms and
decreased again when yellowing became severe (Figures 1 and
2, Tables 2 and 3). The accumulation of carbohydrates leads to
reduced activities of Calvin-cycle enzymes (Krapp et al. 1991,
Stitt et al. 1991). Under high irradiance, a reduction in Calvincycle enzyme activities could result in an over-energization
CARBOHYDRATES IN MAGNESIUM-DEFICIENT NORWAY SPRUCE
and over-reduction of thylakoids and thus cause oxidative
stress. Evidence for this interpretation is provided by the finding that the activity of antioxidative systems in Mg-deficient
Norway spruce needles increased before reductions in chlorophyll concentrations occurred (J. Schittenhelm, S. Westphal,
E. Wagner and B. Mehne-Jakobs, unpublished results).
The accumulation of carbohydrates in Mg-deficient needles
could arise as a result of either a malfunction of phloem
loading, or a reduced demand for carbohydrates in growing
tissues that depend on assimilates such as roots, trunks or
developing shoots (Rufty and Huber 1983, Schaffer et al. 1986,
Sawada et al. 1987, Rufty et al. 1988). In Mg-deficient bush
beans (Phaseolus vulgaris L.), reductions in leaf area increment of developing leaves occur before sucrose and starch
accumulate in mature leaves (Fischer and Bremer 1993). In
trees, the interactions between assimilating leaves and growing
tissues are more complex, because spring growth is dependent
on stored carbohydrates assimilated during the preceding
growing season (Kozlowski et al. 1991). Nevertheless, early
growth reductions, especially in the roots, have been observed
in Mg-deficient Norway spruce (Ingestad 1959, 1979), indicating that carbohydrate accumulation in assimilating needles is
closely associated with reduced growth rates.
Acknowledgments
This research was supported by the Deutsche Forschungsgemeinschaft (DFG). The technical help of Rainer Baritz, Susanne Röske,
Julia Streif and Stefan Türk is gratefully acknowledged.
References
Baule, H. and C. Fricker. 1967. Die Düngung von Waldbäumen.
Bayerischer Landwirtschaftsverlag, München, 259 p.
Bergmann, W. 1988. Ernährungsstörungen bei Kulturpflanzen. G.
Fischer Verlag, Stuttgart, New York, 762 p.
Beringer, H. and H. Forster. 1981. Einfluss variieter Mg-Ernährung
auf Tausendkorngewicht und P-Franktionen des Getreidekorns. Z.
Pflanzenern. Bodenkd. 144:8--15.
Dekker, R.F.M. and G.N. Richards. 1971. Determination of starch in
plant material. J. Sci. Food Agric. 22:441--444.
Einig, W. and R. Hampp. 1990. Carbon partitioning in Norway spruce:
amounts of fructose-2,6-bisphosphate and of intermediates of
starch/sucrose synthesis in relation to needle age and degree of
needle loss. Trees 4:9--15.
Einig, W., P. Weidmann, B. Egger and R. Hampp. 1990. Diurnale
Änderungen im Gehalt an Intermediaten des Energie- und Kohlenhydrat-Stoffwechsels in Fichtennadeln. Kernforschungszentrum
Karlsruhe, KfK-PEF 61:311--321.
Einig, W., P. Weidmann, R. Hampp, Ch. Hagg, U. Rinderle and H.K.
Lichtenthaler. 1991. Tagesgänge der Photosyntheseaktivität in
Fichtennadeln: Gaswechsel, Energiehaushalt und Regulation des
Kohlenhydratstoffwechsels. Kernforschungszentrum Karlsruhe,
KfK-PEF 80:71--80.
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. 45:270--280.
Fink, S. 1983. Histologische und histochemische Untersuchungen an
Nadeln erkrankter Tannen und Fichten im Südschwarzwald. Allg.
Forstzeitschr. 38:660--663.
583
Fink, S. 1991. Structural changes in conifer needles due to Mg and K
deficiency. Fert. Res. 27:23--27.
Fischer, E.S. and W. Bussler. 1988. Effects of magnesium deficiency
on carbohydrates in Phaseolus vulgaris. Z. Pflanzenernähr. Bodenkd. 151:295--298.
Fischer, E.S. and E. Bremer. 1993. Influence of magnesium deficiency
on rates of leaf expansion, starch and sucrose accumulation, and net
assimilation in Phaseolus vulgaris. Physiol. Plant. 89:271--276.
Forschner, W., V. Schmitt and A. Wild. 1989. Investigations on the
starch content and ultrastructure of spruce needles relative to the
occurrence of novel forest decline. Bot. Acta 102:208--221.
Hampp, R. 1992. Comparative evaluation of the effects of gaseous
pollutants, acidic deposition, and mineral deficiencies on the carbohydrate metabolism of trees. Agric. Ecosyst. Environ. 42:333--364.
Hampp, R., W. Einig and R. Keil. 1987. Profile biochemischer Parameter in pflanzlichen Geweben und Zellen mit unterschiedlich
ausgeprägten Schadsymptomen. Kernforschungszentrum Karlsruhe, KfK-PEF 32:1--48.
Ingestad, T. 1959. Studies on the nutrition of forest tree seedlings. II.
Mineral nutrition of spruce. Physiol. Plant. 12:568--593.
Ingestad, T. 1962. Macroelement nutrition of pine, spruce and birch
seedlings in nutrient solutions. Medd. Statens Skogsforskn. 51:1-150.
Ingestad, T. 1979. Mineral nutrient requirements of Pinus sylvestris
and Picea abies seedlings. Physiol. Plant. 45:373--380.
Jones, M.G.K. and W.H. Outlaw. 1981. Enzymatic assay for sucrose.
In Techniques in Carbohydrate Metabolism. Ed. H.L. Kornberg.
B 302 Elsevier, Amsterdam, pp 1--8.
Köstner, B.M. 1989. Jahresverlauf der Chloroplastenpigmente von
ungeschädigten und chlorotischen Fichten an einem Waldschadensstandort im Fichtelgebirge in Abhängigkeit von Alter und Mineralstoffgehalt der Nadeln. Ph.D. Thesis. Bayerische JuliusMaximilians-University, Würzburg, 163 p.
Kozlowski, T.T., P.J. Kramer and S.G. Pallardy. 1991. The physiological ecology of woody plants. Academic Press, San Diego, 657 p.
Krapp, A., W.P. Quick and M. Stitt. 1991. Ribulose-1,5-bisphosphate
carboxylase-oxygenase, other Calvin-cycle enzymes, and chlorophyll decrease when glucose is supplied to mature spinach leaves
via the transpiration stream. Planta 186:58--69.
Laing, W.A. and J.T. Christeller. 1976. A model for the kinetics of
activation and catalysis of ribulose-1,5-bisphosphate carboxylase.
Biochem. J. 159:563--570.
Landoldt, W. and B. Krause-Lüthy. 1989. Nationales Forschungsprogramm 14+. ‘‘Waldschäden und Luftverschmutzung in der
Schweiz’’. Teilprojekt ‘‘Negativbegasung’’, WSL, CH-8903 Birmensdorf, pp 1--120.
Lange, O.L., R.M. Weikert, M. Wedler, J. Gebel and U. Heber. 1989.
Photosynthese und Nährstoffversorgung von Fichten aus einem
Waldschadensgebiet auf basenarmem Untergrund. Allg. Forstzeitschr. 44:55--65.
Lorimer, G.H., M.R. Badger and T.J. Andres. 1976. The activation of
ribulose-1,5-bisphosphate carboxylase by carbon dioxide and magnesium ions. Equilibra, kinetics, a suggested mechanism, and
physiological implications. Biochemistry 15:529--536.
Lichtenthaler, H.K. 1987. Chlorophylls and carotenoids: pigments of
photosynthetic biomembranes. Methods Enzymol. 148:350--382.
Marschner, H. 1986. Mineral nutrition of higher plants. Academic
Press, London, 674 p.
Mies, E. and H.W. Zöttl. 1985. Zeitliche Änderung der chlorophyllund Elementgehalte in den Nadeln eines gelb-chlorotischen Fichtenbestandes. Forstwiss. Centralbl. 104:1--8.
584
MEHNE-JAKOBS
Oren, R., E.-D. Schulze, K.S. Werk, J. Meyer, B.U. Schneider and H.
Heilmeier. 1988. Performance of two Picea abies (L.) Karst. stands
at different stages of decline. I. Carbon relations and stand growth.
Oecologia 75:25--37.
Outlaw, W.H. and J. Manchester. 1979. Guard cell starch concentration
quantitatively related to stomatal aperture. Plant Physiol. 64:79--82.
Reemtsma, J.B. 1986. Der Magnesium-Gehalt von Nadeln niedersächischer Fichtenbestände und seine Beurteilung. Allg. Forstund Jagdztg. 157:196--200.
Rufty, T.W., Jr. and S.C. Huber. 1983. Changes in starch formation and
activities of sucrose phosphate synthase and cytoplasmic fructose1,6-bisphosphatase in response to source--sink alterations. Plant
Physiol. 72:474--480.
Rufty, T.W., Jr., S.C. Huber and R.J. Volk. 1988. Alterations in leaf
carbohydrate metabolism in response to nitrogen stress. Plant
Physiol. 88:725--730.
Sawada, S., H. Kawamura, T. Hayakawa and M. Kasal. 1987. Regulation of photosynthetic metabolism by low-temperature treatment of
roots of single-rooted soybean plants. Plant Cell Physiol. 28:235-241.
Schaffer, A.A., K.-C. Liu, E.F. Goldschmidt, C.D. Boyer and R.
Goren. 1986. Citrus leaf chlorosis induced by sink removal: starch,
nitrogen, and chloroplast ultrastructure. J. Plant Physiol. 124:111-121.
Schulze, E.-D. 1989. Air pollution and forest decline in a spruce
(Picea abies) forest. Science 244:776--783.
Senser, M., F. Schötz and E. Beck. 1975. Seasonal changes in structure
and function of spruce chloroplasts. Planta 126:1--10.
Stitt, M., A. von Schaewen and L. Willmitzer. 1991. ‘Sink’ regulation
of photosynthetic metabolism in transgenic tobacco plants expressing yeast invertase in their cell wall involves a decrease of the
Calvin-cycle enzymes and an increase of glycolytic enzymes.
Planta 183:40--50.
Vogels, K., R. Guderian and G. Masuch. 1986. Studies on Norway
spruce (Picea abies (L.) Karst.) in damaged forest stands and in
climatic chamber experiments. In Acidification and Its Policy Implications. Ed. T. Schneider. Elsevier, Amsterdam, pp 171--186.
Ziegler, R. and K. Egle. 1965. Zur quantitativen Analyse der Chloroplastenpigmente. Beitr. Biol. Pflanz. 41:11--37.
Zöttl, H.W. 1985. Waldschäden und Nährelementversorgung. Düsseldorfer Geobotanisches Kolloquium 2:31--41.
© 1995 Heron Publishing----Victoria, Canada
The influence of magnesium deficiency on carbohydrate
concentrations in Norway spruce ( Picea abies) needles
BEATE MEHNE-JAKOBS
Institut für Forstbotanik und Baumphysiologie, Albert-Ludwigs-Universität, Bertoldstrass
e 17, D-79085 Freiburg, Germany
Received April 5, 1994
Summary Both short- and long-term effects of Mg deficiency on carbohydrate metabolism were investigated in
6-year-old clonal Norway spruce (Picea abies (L.) Karst.) trees
cultivated in sand culture with an optimal supply of nutrients,
except for Mg which was supplied at 0.203, 0.041 and
0.005 mM to provide optimal, moderately deficient and severely deficient Mg supply, respectively. Annual changes in
carbohydrate concentrations (starch, sucrose, glucose and fructose) were analyzed and diurnal changes were investigated on
a single day during the summer.
Older needles of trees in the moderate Mg-deficiency treatment developed tip-yellowing symptoms, whereas currentyear needles remained green. The severe Mg-deficiency
treatment led to pronounced yellowing symptoms in needles of
all ages. Increased carbohydrate concentrations were observed
before needle yellowing occurred. Diurnal and annual changes
in carbohydrates were similar in all treatments; however, carbohydrate concentrations were influenced by Mg supply. In
both Mg-deficiency treatments, starch concentrations increased in needles, especially during summer and autumn.
Starch accumulation was more pronounced at the beginning of
the Mg-deficiency treatments than at the end of the treatments.
Sucrose, and to a minor extent, glucose and fructose concentrations tended to increase in response to Mg deficiency. The
consequences of Mg deficiency on carbohydrate metabolism
are discussed with respect to reduced plant growth and decreased transport rates of carbohydrates to sink organs.
late autumn (Hampp et al. 1987, Einig and Hampp 1990).
Because interactions with environmental factors, such as
drought, acid deposition and air pollutants (e.g., Vogels et al.
1986, Landoldt and Krause-Lüthy 1989, Hampp 1992), may
alter the carbohydrate pools, the effects of Mg deficiency on
carbohydrate metabolism need to be studied under controlled
conditions.
A deficiency in Mg nutrition can affect carbon metabolism
in many ways causing reductions as well as accumulations of
specific carbohydrates. Because Mg is a constituent of the
chlorophyll molecule and is also a cofactor of a series of
enzymes involved in carbon fixation, it is essential for photosynthesis (Laing and Christeller 1976, Lorimer et al. 1976).
Magnesium is also required for ATP metabolism and is, therefore, essential for many metabolic processes, including carbohydrate metabolism and the synthesis of proteins, fats and
nucleic acids. It is also a key element in membrane transport
(Marschner 1986).
The main objective of this study was to test the hypothesis
that Mg deficiency results in the accumulation of carbohydrates in Norway spruce needles. We investigated short-term
and long-term effects of Mg deficiency on starch, sucrose,
glucose and fructose concentrations in needles, and we also
evaluated diurnal and annual changes in carbohydrates with
respect to Mg nutrition and needle age.
Keywords: carbohydrate metabolism, fructose, glucose,
growth, starch accumulation, sucrose.
Materials and methods
Plant material and study design
Introduction
There is evidence that, in Norway spruce (Picea abies (L.)
Karst.) needles from stands showing forest decline symptoms,
changes in pool sizes of carbohydrates are caused by Mg
deficiency. Accumulations of starch in yellowing needles of
declining Norway spruce trees have been observed by Fink
(1983), Oren et al. (1988) and Forschner et al. (1989); however,
Hampp and colleagues did not find any changes in starch
concentrations, perhaps as a result of the interactive effects of
other stress factors, although they did observe a longer retention of starch in yellowing needles than in green needles during
Two experiments, one long term (Experiment 1) and one short
term (Experiment 2), were conducted during the growing seasons of 1990 and 1991, respectively. In Experiment 1, 100
six-year-old Norway spruce trees of Clone 1382/113 (provenance Rothenkirchen 84011, Frankenwald, Germany) were
planted in an outdoor facility in spring 1988. In Experiment 2,
100 five-year-old Norway spruce trees of Clone 1213/113 of
the same provenance were planted in October 1990. In both
experiments, the nonmycorrhizal trees were cultivated in sand
culture in 70-liter pots and individually supplied with nutrients
by means of a continuously circulating solution, which was
replaced once a week. The nutrient solutions were adjusted to
achieve optimum growth according to the principles set out by
578
MEHNE-JAKOBS
Ingestad (1959, 1979). One liter of nutrient solution contained:
50 mg KNO3, 68 mg KH2PO4, 65 mg Ca(NO3)2⋅4H2O, 11.5 mg
(NH4)2HPO4, 90 mg NH4NO3, 50 mg MgSO4⋅7H2O, 5 mg
Fe-EDTA, 800 µg MnSO4⋅4H2O, 80 µg CuSO4⋅5H2O, 200 µg
ZnSO4⋅7H2O, 600 µg H3BO3, 17.5 µg Na2MoO4⋅1H2O plus
magnesium as specified. Magnesium was added to the nutrient
solutions to provide concentrations of 0.203 (optimal, Treatment 1), 0.041 (moderately deficient, Treatment 2) and 0.005
mM (severely deficient, Treatment 3). Sulfate in the Mg-deficiency treatments was supplied as Na2SO4⋅10H2O in concentrations corresponding to the deficiency treatments.
1 h (Dekker and Richards 1971). To remove free glucose, the
extract was incubated at 95 °C for 3 min, adjusted to pH 4.6
with 0.5 M acetic acid, and then centrifuged at 10,000 g for
5 min (Einig and Hampp 1990). Aliquots of 20 to 60 µl of the
supernatant were used for the enzymatic determination of
starch according to Outlaw and Manchester (1979).
Chlorophyll concentrations were determined after extraction in 80% acetone (Ziegler and Egle 1965), and calculated
according to Lichtenthaler (1987). Magnesium concentrations
of needles were analyzed by the AAS--AES flame technique
(Perkin Elmer 4000, Ueberlingen, Germany) after dry ashing
and digestion with HNO3-HCl.
Sampling conditions
In Experiment 1, current-year to 2-year-old needles were taken
from the fourth whorl between 0800 and 0930 h MET (MidEuropean Time) in May, June, August and October 1990, and
in March 1991 for carbohydrate analysis. In Experiment 2,
needles were taken from current-year and 1-year-old twigs of
the third whorl in July, August and September 1991 for carbohydrate analysis. Samples were collected between 1100 and
1230 h MET at high irradiance (> 1200 µmol m −2 s −1) after a
period of at least 2 days with bright sunshine. In both experiments, samples were taken from six trees per Mg treatment,
and all samples were taken from the sun-exposed, upper side
of the twigs. For the study of diurnal changes in carbohydrates,
needles from trees in the optimal-Mg treatment and the severe
Mg-deficiency treatment were sampled from current-year and
1-year-old shoots every 2 and 4 h, respectively, between 0400
and 2200 h MET on August 22, 1991, a day following a period
of high temperatures and high irradiance.
For the determination of Mg, needle samples were taken
from current-year to 2-year-old southerly exposed twigs of the
fourth whorl in October 1990 and 1991. Five samples of each
treatment and age class were combined to form one mixed
sample. Magnesium was assayed in two and five replicates of
the mixed samples in 1990 and 1991, respectively.
Temperature, relative humidity and solar irradiance, measured with a quantum sensor (Li-Cor Inc., Lincoln, NE), were
recorded at each sampling time.
The needle samples were immediately frozen in liquid nitrogen and stored at −80 °C. Frozen needle tissue was homogenized with a microdismembrator (Braun, Melsungen,
Germany), and the resulting powder was freeze-dried at
−25 °C and stored under vacuum at −20 °C.
Measurements
Concentrations of sucrose, glucose and fructose in the needles
were determined according to Einig and Hampp (1990). Two
mg of lyophilized needle homogenate was extracted in 1 ml of
65% (v/v) aqueous ethanol at 70 °C for 1 h. Activated charcoal
(2%, w/v) was used in order to reduce the blank reading. The
mixture was then centrifuged at 10,000 g for 5 min, and 20 to
200 µl aliquots of the supernatant were assayed according to
Jones and Outlaw (1981).
To determine needle starch concentrations, 2 to 6 mg
aliquots of needle homogenate were extracted with 0.5 ml of
0.5 M NaOH in Eppendorff vials at ambient temperature for
Statistical analysis
Means and standard errors (SE) were calculated separately for
each sampling time and each needle age class. Differences
among the treatments within each needle age class were evaluated by analysis of variance and Tukey’s test performed with
the SPSS-PC+ software package.
Results
After 3 years of adaptation to Mg deficiency, Mg concentrations in needles of Norway spruce trees closely paralleled the
nutrient regimes, with lowest values in the severe Mg-deficiency treatment (Table 1). Trees in the long-term moderate
Mg-deficiency treatment showed typical symptoms of Mg
deficiency, including tip-yellowing of the 1- and 2-year-old
needles. The current-year needles, which developed in May,
remained green throughout the growing season, and their chlorophyll concentrations did not differ from those of the controls
(Figure 1). In contrast, in the long-term, severe Mg-deficiency
treatment, needles of all age classes displayed pronounced
yellowing (Figure 1). The short-term Mg-deficiency treatments resulted in lower needle Mg concentrations than the
long-term Mg-deficiency treatments (Table 1). In the shortterm Mg-deficiency treatments, the first deficiency symptoms
became visible in July. One-year-old needles of trees in the
short-term, moderate Mg-deficiency treatment exhibited tipyellowing, whereas the current-year needles remained green
and had chlorophyll concentrations comparable to those of
Table 1. Magnesium concentrations (mg g DW−1) in current-year, and
1- and 2-year-old needles of Norway spruce trees subjected to longterm (Experiment 1, n = 2) or short-term (Experiment 2, n = 5)
Mg-deficiency treatments.
Needle age
Control
Moderate
deficiency
Severe
deficiency
Experiment 1
Current-year
One-year-old
Two-year-old
2.39
2.07
2.05
0.93
0.56
0.47
0.48
0.32
0.34
Experiment 2
Current-year
One-year-old
Two-year-old
1.33
1.07
1.20
0.59
0.46
0.46
0.24
0.33
0.28
CARBOHYDRATES IN MAGNESIUM-DEFICIENT NORWAY SPRUCE
579
Table 2. Chlorophyll concentrations (µg g FW−1) in current-year and
1-year-old needles of Norway spruce trees subjected to short-term
Mg-deficiency treatments (Experiment 2, means ± SE, n = 6). Significant differences between the treatments: ** = P < 0.01, *** = P <
0.001. Values followed by different letters differ significantly among
the treatments (Tukey’s test, P < 0.05).
Sampling
Figure 1. Chlorophyll concentrations in current-year, and 1- and 2year-old needles of Norway spruce trees adapted to Mg deficiency
(Experiment 1) (d controls, j moderate Mg deficiency, and . severe
Mg deficiency). Means of nine samples ± SE are presented for each
month (significant differences between treatments: * = P < 0.05, ** =
P < 0.01, and *** = P < 0.001).
control needles (Table 2). In the short-term, severe Mg-deficiency treatment, yellowing symptoms were most pronounced
among the current-year needles. Throughout the growing season, chlorophyll concentrations of needles in the short-term
severe Mg-deficiency treatment were significantly lower than
those of control needles (Table 2).
As a consequence of long-term Mg deficiency, starch concentrations increased in the current-year needles after their
maturation from August onward (Figure 2). In addition, the
Mg-deficiency treatments resulted in higher sucrose and fructose concentrations in the current-year needles in August 1990
and March 1991, respectively, than in the corresponding con-
Control
Moderate
deficiency
Severe
deficiency
Current-year needles
July
1730 ± 48 a
August
2013 ± 108 a
September
2020 ± 71 a
1731 ± 56 a
1777 ± 75 ab
1981 ± 52 a
1343 ± 117 b**
1347 ± 179 b**
1431 ± 140 b***
One-year-old needles
July
2334 ± 79 a
August
2463 ± 119 a
September
2662 ± 130 a
1859 ± 111 b
1537 ± 215 b
1870 ± 131 b
1702 ± 125 b**
1672 ± 188 b**
1471 ± 81 b***
trol needles. One-year-old Mg-deficient needles exhibited a
decrease in starch accumulation in May, when the development of new shoots started (Figure 3), and this was accompanied by increased concentrations of glucose and fructose in
May and June. Significant increases in sucrose concentrations
occurred in 1-year-old needles in the moderate- and severe
Mg-deficiency treatments in May and October, respectively.
As observed in current-year needles, the Mg-deficiency treatments caused increases in starch concentrations of 2-year-old
needles in August and October and increases in sucrose concentrations throughout the measuring period (Figure 4). The
well-known annual changes in starch, glucose and fructose
concentrations, which generally reflect growth and developmental processes in the trees, were observed in all treatments.
The accumulation of starch in the short-term Mg-deficiency
treatment was even more pronounced than in the long-term
experiment, especially in 1-year-old needles (Table 3). The
needles in the moderate Mg-deficiency treatment exhibited
peak concentrations of glucose and fructose in July. A significant increase in sucrose concentration also occurred in July in
both current-year and 1-year-old needles of the severe Mg-deficiency treatment and in 1-year-old needles of the moderate
Mg-deficiency treatment. However, in August, sucrose concentrations decreased in both needle age classes of the severe
Mg-deficiency treatment in parallel with large increases in
starch concentrations.
In August 1991, diurnal changes in carbohydrate concentrations were followed in samples from trees in the control and
severe Mg-deficiency treatments after a period of high temperatures and intensive irradiance. During daytime, the temperature reached 35 °C, and relative humidity declined to
about 20% (Figure 5). As a consequence of the hazy sky,
photosynthetically active radiation (PAR) was saturating for
photosynthesis for only a few hours around noon. Starch concentrations of the current-year control needles showed only
minor alterations during daytime, whereas starch concentrations in the severe Mg-deficiency treatment decreased
throughout the day (Figure 6). Although chlorophyll concentrations were reduced in current-year needles of the severe
580
MEHNE-JAKOBS
Figure 2. Starch, sucrose, glucose and fructose concentrations in
current-year needles of Norway spruce trees adapted to Mg deficiency
(Experiment 1) (d controls, j moderate Mg deficiency, and . severe
Mg deficiency). Means of six samples ± SE are presented for each
month (significant differences between treatments: * = P < 0.05, and
** = P < 0.01). Note the additional scale for the October data.
Mg-deficiency treatment, starch accumulation was five times
greater than that of the control needles. Sucrose concentrations
rose in the morning and then remained constant throughout the
day. Treatment-related increases in sucrose concentration were
only observed in the morning. In the evening, glucose and
fructose concentrations increased in the Mg-deficiency treatment. Short-term Mg deficiency also resulted in increased
starch concentrations in 1-year-old needles, but values varied
greatly (Figure 7).
Figure 3. Starch, sucrose, glucose and fructose concentrations in
1-year-old needles of Norway spruce trees adapted to Mg deficiency
(Experiment 1) (d controls, j moderate Mg deficiency, and . severe
Mg deficiency). Means of six samples ± SE are presented for each
month (significant differences between treatments: * = P < 0.05, ** =
P < 0.01, and *** = P < 0.001). Note the additional scale for the
October data.
Discussion
Symptoms of Mg deficiency in Norway spruce typically occur
as tip-yellowing in older needles, whereas the current-year
needles remain green (Baule and Fricker 1967, Zöttl 1985,
Bergmann 1988). A similar pattern of symptoms was observed
in trees in the short-term, moderate Mg-deficiency treatment;
however, even current-year needles developed severe chlorosis
in the short-term, severe Mg-deficiency treatment. As observed
in the field (Mies and Zöttl 1985, Lange et al. 1989), the
yellowing symptoms were more intense on the upper, sun-ex-
CARBOHYDRATES IN MAGNESIUM-DEFICIENT NORWAY SPRUCE
581
Table 3. Starch (nmol glycosyl units mg DW−1), sucrose, glucose and
fructose concentrations (nmol mg DW−1) in current-year and 1-year-old
needles of Norway spruce subjected to short-term Mg-deficiency
treatments (Experiment 2, means ± SE, n = 6; for further explanations,
see Table 2).
Sampling
Starch
Current-year
July
August
September
One-year-old
July
August
September
Sucrose
Current-year
July
August
One-year-old
July
August
Glucose
Current-year
July
August
One-year-old
July
August
Fructose
Current-year
July
August
One-year-old
July
August
Control
Moderate
deficiency
Severe
deficiency
133 ± 36
1.8 ± 0.2 a
7.0 ± 0.6
152 ± 51
3.6 ± 0.7 a
10.4 ± 2.3
128 ± 49
39.8 ± 9.2 b***
9.3 ± 1.4
43 ± 11 a
1.7 ± 0.2 a
9.8 ± 2.0 a
245 ± 99 b
11.6 ± 5.2 a
22.4 ± 4.2 b
108 ± 15 a***
61.1 ± 16.9 b**
19.2 ± 1.5 ab*
179 ± 4 a
152 ± 3 a
184 ± 2 a
167 ± 11 a
202 ± 5 b**
117 ± 3 b***
150 ± 7 a
120 ± 4 a
193 ± 6 b
132 ± 8 a
177 ± 4 b***
109 ± 1 b**
11 ± 0.4 a
8 ± 0.3
17 ± 1.7 b
7 ± 0.5
10 ± 0.8 a***
7 ± 0.9
6 ± 0.5 a
6 ± 0.3
10 ± 0.1 b
5 ± 0.4
6 ± 0.4 a**
6 ± 0.6
10 ± 0.8 ab
5 ± 0.3
13 ± 1.2 a
4 ± 0.4
7 ± 0.6 b**
4 ± 0.5
5 ± 0.3 a
3 ± 0.2
8 ± 0.8 b
3 ± 0.2
4 ± 0.3 a***
3 ± 0.4
Figure 4. Starch, sucrose, glucose and fructose concentrations in
2-year-old needles of Norway spruce trees adapted to Mg deficiency
(Experiment 1) (d controls, j moderate Mg deficiency, and . severe
Mg deficiency). Means of six samples ± SE are presented for each
month (significant differences between treatments: * = P < 0.05, ** =
P < 0.01, and *** = P < 0.001). Note the additional scale for the
October data.
posed sides of the needles than on the lower, shaded sides. This
pattern of deficiency symptoms continued throughout the 3year study and was not accompanied by tree mortality. Chlorophyll concentrations were reduced when the Mg
concentration of the needles was less than 0.5 mg g DW−1. This
value is between the threshold values of 0.7 mg g DW−1 reported
for Norway spruce seedlings (Ingestad 1962) and 0.3 mg
g DW−1 reported for older trees (Reemtsma 1986, Köstner 1989,
Schulze 1989). The differences in the threshold values might
be associated with tree age or with differences in nitrogen
nutrition (Ingestad 1979).
Figure 5. Diurnal course of temperature (d), relative humidity (j)
and light intensity (m) on August 22, 1991.
The observed diurnal and annual dynamics of carbohydrate
concentrations in the needles confirms earlier studies (Senser
et al. 1975, Ericsson 1979, Fink 1983, Forschner et al. 1989,
582
MEHNE-JAKOBS
Figure 6. Diurnal course of starch, sucrose, glucose and fructose
concentrations in current-year needles of Norway spruce trees under
short-term Mg-deficiency treatment (Experiment 2) (d controls, and
. severe Mg deficiency). Means of three samples ± SE are presented
for each month (significant differences between treatments: * = P <
0.05, and ** = P < 0.01).
Figure 7. Diurnal course of starch, sucrose, glucose and fructose
concentrations in 1-year-old needles of Norway spruce trees under
short-term Mg-deficiency treatment (Experiment 2) (d controls, and
. severe Mg deficiency). Means of three samples ± SE are presented
for each month (significant differences between treatments: * = P <
0.05, ** = P < 0.01, and *** = P < 0.001).
Einig and Hampp 1990, Einig et al. 1990, 1991). Similar
diurnal and annual fluctuations were observed in all treatments, but carbohydrate concentrations were influenced by the
Mg-deficiency treatments. Needles in both Mg-deficiency
treatments exhibited an increase in starch concentrations, especially during summer and autumn, and in the short-term
Mg-deficiency treatment. In addition, sucrose and, to a minor
extent, glucose and fructose concentrations increased in response to the Mg-deficiency treatments. Similar increases in
carbohydrates have been observed in leaves of Mg-deficient
herbaceous plants in association with decreases in the accumulation of assimilates in sink organs (Beringer and Forster 1981,
Fischer and Bussler 1988, Fischer and Bremer 1993). Fink
(1991) observed starch accumulation in the chloroplasts of
Norway spruce needles, suffering from experimentally induced Mg deficiency.
The accumulation of starch began before the reduction in
chlorophyll concentration occurred. Starch accumulation was
highest in needles exhibiting slight yellowing symptoms and
decreased again when yellowing became severe (Figures 1 and
2, Tables 2 and 3). The accumulation of carbohydrates leads to
reduced activities of Calvin-cycle enzymes (Krapp et al. 1991,
Stitt et al. 1991). Under high irradiance, a reduction in Calvincycle enzyme activities could result in an over-energization
CARBOHYDRATES IN MAGNESIUM-DEFICIENT NORWAY SPRUCE
and over-reduction of thylakoids and thus cause oxidative
stress. Evidence for this interpretation is provided by the finding that the activity of antioxidative systems in Mg-deficient
Norway spruce needles increased before reductions in chlorophyll concentrations occurred (J. Schittenhelm, S. Westphal,
E. Wagner and B. Mehne-Jakobs, unpublished results).
The accumulation of carbohydrates in Mg-deficient needles
could arise as a result of either a malfunction of phloem
loading, or a reduced demand for carbohydrates in growing
tissues that depend on assimilates such as roots, trunks or
developing shoots (Rufty and Huber 1983, Schaffer et al. 1986,
Sawada et al. 1987, Rufty et al. 1988). In Mg-deficient bush
beans (Phaseolus vulgaris L.), reductions in leaf area increment of developing leaves occur before sucrose and starch
accumulate in mature leaves (Fischer and Bremer 1993). In
trees, the interactions between assimilating leaves and growing
tissues are more complex, because spring growth is dependent
on stored carbohydrates assimilated during the preceding
growing season (Kozlowski et al. 1991). Nevertheless, early
growth reductions, especially in the roots, have been observed
in Mg-deficient Norway spruce (Ingestad 1959, 1979), indicating that carbohydrate accumulation in assimilating needles is
closely associated with reduced growth rates.
Acknowledgments
This research was supported by the Deutsche Forschungsgemeinschaft (DFG). The technical help of Rainer Baritz, Susanne Röske,
Julia Streif and Stefan Türk is gratefully acknowledged.
References
Baule, H. and C. Fricker. 1967. Die Düngung von Waldbäumen.
Bayerischer Landwirtschaftsverlag, München, 259 p.
Bergmann, W. 1988. Ernährungsstörungen bei Kulturpflanzen. G.
Fischer Verlag, Stuttgart, New York, 762 p.
Beringer, H. and H. Forster. 1981. Einfluss variieter Mg-Ernährung
auf Tausendkorngewicht und P-Franktionen des Getreidekorns. Z.
Pflanzenern. Bodenkd. 144:8--15.
Dekker, R.F.M. and G.N. Richards. 1971. Determination of starch in
plant material. J. Sci. Food Agric. 22:441--444.
Einig, W. and R. Hampp. 1990. Carbon partitioning in Norway spruce:
amounts of fructose-2,6-bisphosphate and of intermediates of
starch/sucrose synthesis in relation to needle age and degree of
needle loss. Trees 4:9--15.
Einig, W., P. Weidmann, B. Egger and R. Hampp. 1990. Diurnale
Änderungen im Gehalt an Intermediaten des Energie- und Kohlenhydrat-Stoffwechsels in Fichtennadeln. Kernforschungszentrum
Karlsruhe, KfK-PEF 61:311--321.
Einig, W., P. Weidmann, R. Hampp, Ch. Hagg, U. Rinderle and H.K.
Lichtenthaler. 1991. Tagesgänge der Photosyntheseaktivität in
Fichtennadeln: Gaswechsel, Energiehaushalt und Regulation des
Kohlenhydratstoffwechsels. Kernforschungszentrum Karlsruhe,
KfK-PEF 80:71--80.
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. 45:270--280.
Fink, S. 1983. Histologische und histochemische Untersuchungen an
Nadeln erkrankter Tannen und Fichten im Südschwarzwald. Allg.
Forstzeitschr. 38:660--663.
583
Fink, S. 1991. Structural changes in conifer needles due to Mg and K
deficiency. Fert. Res. 27:23--27.
Fischer, E.S. and W. Bussler. 1988. Effects of magnesium deficiency
on carbohydrates in Phaseolus vulgaris. Z. Pflanzenernähr. Bodenkd. 151:295--298.
Fischer, E.S. and E. Bremer. 1993. Influence of magnesium deficiency
on rates of leaf expansion, starch and sucrose accumulation, and net
assimilation in Phaseolus vulgaris. Physiol. Plant. 89:271--276.
Forschner, W., V. Schmitt and A. Wild. 1989. Investigations on the
starch content and ultrastructure of spruce needles relative to the
occurrence of novel forest decline. Bot. Acta 102:208--221.
Hampp, R. 1992. Comparative evaluation of the effects of gaseous
pollutants, acidic deposition, and mineral deficiencies on the carbohydrate metabolism of trees. Agric. Ecosyst. Environ. 42:333--364.
Hampp, R., W. Einig and R. Keil. 1987. Profile biochemischer Parameter in pflanzlichen Geweben und Zellen mit unterschiedlich
ausgeprägten Schadsymptomen. Kernforschungszentrum Karlsruhe, KfK-PEF 32:1--48.
Ingestad, T. 1959. Studies on the nutrition of forest tree seedlings. II.
Mineral nutrition of spruce. Physiol. Plant. 12:568--593.
Ingestad, T. 1962. Macroelement nutrition of pine, spruce and birch
seedlings in nutrient solutions. Medd. Statens Skogsforskn. 51:1-150.
Ingestad, T. 1979. Mineral nutrient requirements of Pinus sylvestris
and Picea abies seedlings. Physiol. Plant. 45:373--380.
Jones, M.G.K. and W.H. Outlaw. 1981. Enzymatic assay for sucrose.
In Techniques in Carbohydrate Metabolism. Ed. H.L. Kornberg.
B 302 Elsevier, Amsterdam, pp 1--8.
Köstner, B.M. 1989. Jahresverlauf der Chloroplastenpigmente von
ungeschädigten und chlorotischen Fichten an einem Waldschadensstandort im Fichtelgebirge in Abhängigkeit von Alter und Mineralstoffgehalt der Nadeln. Ph.D. Thesis. Bayerische JuliusMaximilians-University, Würzburg, 163 p.
Kozlowski, T.T., P.J. Kramer and S.G. Pallardy. 1991. The physiological ecology of woody plants. Academic Press, San Diego, 657 p.
Krapp, A., W.P. Quick and M. Stitt. 1991. Ribulose-1,5-bisphosphate
carboxylase-oxygenase, other Calvin-cycle enzymes, and chlorophyll decrease when glucose is supplied to mature spinach leaves
via the transpiration stream. Planta 186:58--69.
Laing, W.A. and J.T. Christeller. 1976. A model for the kinetics of
activation and catalysis of ribulose-1,5-bisphosphate carboxylase.
Biochem. J. 159:563--570.
Landoldt, W. and B. Krause-Lüthy. 1989. Nationales Forschungsprogramm 14+. ‘‘Waldschäden und Luftverschmutzung in der
Schweiz’’. Teilprojekt ‘‘Negativbegasung’’, WSL, CH-8903 Birmensdorf, pp 1--120.
Lange, O.L., R.M. Weikert, M. Wedler, J. Gebel and U. Heber. 1989.
Photosynthese und Nährstoffversorgung von Fichten aus einem
Waldschadensgebiet auf basenarmem Untergrund. Allg. Forstzeitschr. 44:55--65.
Lorimer, G.H., M.R. Badger and T.J. Andres. 1976. The activation of
ribulose-1,5-bisphosphate carboxylase by carbon dioxide and magnesium ions. Equilibra, kinetics, a suggested mechanism, and
physiological implications. Biochemistry 15:529--536.
Lichtenthaler, H.K. 1987. Chlorophylls and carotenoids: pigments of
photosynthetic biomembranes. Methods Enzymol. 148:350--382.
Marschner, H. 1986. Mineral nutrition of higher plants. Academic
Press, London, 674 p.
Mies, E. and H.W. Zöttl. 1985. Zeitliche Änderung der chlorophyllund Elementgehalte in den Nadeln eines gelb-chlorotischen Fichtenbestandes. Forstwiss. Centralbl. 104:1--8.
584
MEHNE-JAKOBS
Oren, R., E.-D. Schulze, K.S. Werk, J. Meyer, B.U. Schneider and H.
Heilmeier. 1988. Performance of two Picea abies (L.) Karst. stands
at different stages of decline. I. Carbon relations and stand growth.
Oecologia 75:25--37.
Outlaw, W.H. and J. Manchester. 1979. Guard cell starch concentration
quantitatively related to stomatal aperture. Plant Physiol. 64:79--82.
Reemtsma, J.B. 1986. Der Magnesium-Gehalt von Nadeln niedersächischer Fichtenbestände und seine Beurteilung. Allg. Forstund Jagdztg. 157:196--200.
Rufty, T.W., Jr. and S.C. Huber. 1983. Changes in starch formation and
activities of sucrose phosphate synthase and cytoplasmic fructose1,6-bisphosphatase in response to source--sink alterations. Plant
Physiol. 72:474--480.
Rufty, T.W., Jr., S.C. Huber and R.J. Volk. 1988. Alterations in leaf
carbohydrate metabolism in response to nitrogen stress. Plant
Physiol. 88:725--730.
Sawada, S., H. Kawamura, T. Hayakawa and M. Kasal. 1987. Regulation of photosynthetic metabolism by low-temperature treatment of
roots of single-rooted soybean plants. Plant Cell Physiol. 28:235-241.
Schaffer, A.A., K.-C. Liu, E.F. Goldschmidt, C.D. Boyer and R.
Goren. 1986. Citrus leaf chlorosis induced by sink removal: starch,
nitrogen, and chloroplast ultrastructure. J. Plant Physiol. 124:111-121.
Schulze, E.-D. 1989. Air pollution and forest decline in a spruce
(Picea abies) forest. Science 244:776--783.
Senser, M., F. Schötz and E. Beck. 1975. Seasonal changes in structure
and function of spruce chloroplasts. Planta 126:1--10.
Stitt, M., A. von Schaewen and L. Willmitzer. 1991. ‘Sink’ regulation
of photosynthetic metabolism in transgenic tobacco plants expressing yeast invertase in their cell wall involves a decrease of the
Calvin-cycle enzymes and an increase of glycolytic enzymes.
Planta 183:40--50.
Vogels, K., R. Guderian and G. Masuch. 1986. Studies on Norway
spruce (Picea abies (L.) Karst.) in damaged forest stands and in
climatic chamber experiments. In Acidification and Its Policy Implications. Ed. T. Schneider. Elsevier, Amsterdam, pp 171--186.
Ziegler, R. and K. Egle. 1965. Zur quantitativen Analyse der Chloroplastenpigmente. Beitr. Biol. Pflanz. 41:11--37.
Zöttl, H.W. 1985. Waldschäden und Nährelementversorgung. Düsseldorfer Geobotanisches Kolloquium 2:31--41.