Environmental and Experimental Botany 43 2000 253 – 265
Non-structural carbohydrate status in Norway spruce buds in the context of annual bud structural development as
affected by acidic pollution
Hana Svobodova´, Helena Lipavska´, Jana Albrechtova´
Department of Plant Physiology, Faculty of Science, Charles Uni6ersity, Vinicˇna´
5
, CZ-
128 44
Prague
2
, Czech Republic Received 14 August 1999; received in revised form 19 November 1999; accepted 20 November 1999
Abstract
The present study focused on changes in the annual dynamics of the contents of non-structural saccharides NSS of Norway spruce vegetative buds related to their structural development under the effect of acidic pollution during
the year 1995. Two types of material were analysed: 1 4-year-old trees treated for 2 years by simulated acid rain SAR; pH 2.9 and 3.9, and 2 40 – 60-year-old trees growing in natural mountain stands exhibiting different degrees
of macroscopic damage. Our study revealed that the dynamics of the NSS content reflected the major morphogenetic and developmental changes occurring during the annual bud developmental cycle. No systematic changes in the
annual dynamics of NSS content were observed in buds from both mountain sites, or as a consequence of the SAR. The total sugar content of bud tissues was composed of a combination of five main sugar components: sucrose,
glucose, fructose, raffinose family oligosaccharides RFO; combination of raffinose and stachyose, and a pinitol fraction PF probably of cyclitols with pinitol as a main member. The dynamics of individual sugar components also
reflected possible carbohydrate mediated bud frost protection. Interesting results were obtained from buds in dormant state. In dormant buds of the SAR experiment the higher value of the ratio PF:RFO of the pinitol fraction and
raffinose family oligosaccharides followed the higher dose of SAR treatment. When evaluating the ratio from both types of material we assumed that changes in PF:RFO ratio corresponded to early stages of damage or acute
metabolic reaction. Thus, we suggest the ratio PF:RFO as a possible non-specific metabolic marker of early bud stress reaction which is, among other stress factors, sensitive to increasing load of acidic pollutants. © 2000 Elsevier Science
B.V. All rights reserved.
Keywords
:
Acid rain; Picea abies; Pinitol; Raffinose; Starch; Sugars www.elsevier.comlocateenvexpbot
1. Introduction
Within the last 25 – 35 years air pollution has become a potential threat to forest production
world-wide. Sulphur dioxide and nitrogen oxides are known as major pollutants in industrial areas,
Corresponding author. Tel.: + 420-2-2195-3185; fax: + 420-2-2195-3306.
E-mail address
:
albrechtnatur.cuni.cz J. Albrechtova´ S0098-847200 - see front matter © 2000 Elsevier Science B.V. All rights reserved.
PII: S 0 0 9 8 - 8 4 7 2 9 9 0 0 0 6 2 - 3
primarily as causative agents of acid rain. The effect of acidic pollution expressed by anatomical
andor morphological changes is initially recog- nisable at the level of metabolic detection. Several
studies of Norway spruce have shown that distur- bances caused by SO
2
in the biochemical function Hampp, 1992 and the cell ultrastructure Ka¨ren-
lampi, 1986 of plants appear before visual symp- toms
or growth
reduction. To
enable the
necessary measures to be taken in time, metabolic markers for the detection of early damage are of
great importance for forest management. The carbohydrate status of plant organs is quite
a sensitive indicator of the physiological responses to natural and anthropogenic stresses, such as
dust pollution Mandre and Kloseiko, 1997, soil acidification and water availability Kleinschmidt
et al., 1998, acid mist and frost drought Esch and Mengel, 1998. In addition, the effects of
air-borne pollutants on the saccharide metabolism of coniferous needles have been investigated, how-
ever, the reported results were controversial. For example, a decrease in the contents of hexoses,
sucrose and starch was observed as a consequence of the simulated effect of SO
2
in combination with O
3
Hampp et al., 1990; Peace et al., 1995. In contrast Ku¨ppers and Klumpp 1988 reported
elevated levels of the contents of starch and sug- ars when needles were exposed to a similar stress
load. Data on the effect of indigenous acidic deposition on natural mountainous stands are still
scarce because of stand heterogeneity and interac- tions of acting abiotic and biotic factors. Oren et
al. 1988 analysed healthy, dark green needles and apparently yellowing ones macroscopically,
and found that yellowing needles contained a higher amount of total soluble saccharides when
compared with healthy needles, whilst differences in starch accumulation were not observed.
In conifer needles, changes in partitioning be- tween starch and sugars favouring the accumula-
tion of soluble sugars before the winter period were supposed to be involved in frost hardening.
These changes are an important contributor to the increased frost tolerance of conifers in winter
when sugars can act as cryoprotectants Kandler and Hopf, 1982; Hampp, 1992; Ogren, 1997;
Ogren et al., 1997. The increase in total sugar content during cold hardening, however, may not
to be of primary importance as the ratio between particular sugars might prove to be crucial for
cryoprotection Obendorf, 1997; Liu et al., 1998. For example, sucrose is known to be able to
retain the liquid-crystalline state of membranes under osmotic stress. Conifers frequently experi-
ence subfreezing temperatures as well as substan- tial water stress Tranquillini, 1979 which might
promote sucrose crystallisation and thus a loss of the cryoprotective effects of this sugar. Raffinose
is supposed to inhibit the tendency of sucrose to crystallise and therefore to conserve the protective
quality of sucrose Caffrey et al., 1988. Other substances from plant carbohydrate spectrum,
such as cyclitols, are also believed to have roles as cryoprotectants, desiccation protectants, and hy-
droxyl radical scavengers Obendorf, 1997; Nel- son and Bartels, 1998.
Bud apical meristems are very important sinks as they determine further growth and develop-
ment of tree species. Bud physiological state in- cluding saccharide metabolism will determine
their growth capacity, and thus the development of the whole crown architecture. Only limited
information is available about changes in the dynamics of non-structural saccharide NSS con-
tent in buds of Norway spruce under stress condi- tions Lux et al., 1997. According to our
knowledge nothing is known about the effect of acidic pollution. Thus, the aim of this study was
to determine the effect of acid rain on the content of NSS in buds of Norway spruce Picea abies
during 1 year of their development. We tested the hypothesis that changes in contents and composi-
tion of non-structural carbohydrates in buds of Norway spruce are indicators of early damage or
acute metabolic reaction caused by the effect of acid rain as a main stressor.
2. Materials and methods
