Genetic Effects of Air Pollutants in Forest Tree Populations: Proceedings of the Joint Meeting of the IUFRO Working Parties Genetic Aspects of Air Pollution Population and Ecological Genetics Biochemical Genetics held in Großhansdorf, August 3–7, 1987

196 Pages·1989·4.73 MB·English

by  Hans-Rolf Gregorius (auth.)

F. Scholz H.-R. Gregorius D. Rudin (Eds.)
Genetic Effects
of Air Pollutants
in Forest Tree Populations
Proceedings of the Joint Meeting of the IUFRO Working Parties
Genetic Aspects of Air Pollution
Population and Ecological Genetics
Biochemical Genetics
held in GroBhansdorf, August 3-7, 1987
With 34 Figures
Springer-Verlag Berlin Heidelberg New York
London Paris Tokyo Hong Kong
FLORIAN SCHOLZ
Bundesforschungsanstalt flir
Forst- und Holzwirtschaft
Institut flir Forstgenetik
und Forstpflanzenziichtung
Sieker LandstraBe 2
D-2070 GroBhansdorf 2
HANS-ROLF GREGORIUS
Georg-August UniversiHit Gottingen
Abt. flir Forstgenetik und
Forstpflanzenziichtung
Biisgenweg 2
D-3400 Gottingen
DAG RUDIN
Department of Forest Genetics
and Plant Physiology
S-90183 Umea
ISBN-13 :978-3-642-74550-8 e-ISBN-13: 978-3-642-74548-5
DOl: 10.1007/978-3-642-74548-5
Library of Congress Cataloging-in-Publication Data. Genetic effects of air pollutants in forest tree popula·
tions. Proceedings of the joint meeting of the IUFRO working parties Genetic Aspects of Air Pollution,
Population and Ecological Genetics, Biochemical Genetics, held in Grosshansdorf, August 3-7, 1987.
Includes index. 1. Trees-Effect of air pollution on-Genetic aspects-Congresses. 2. Forest genetics
Congresses. I. Scholz, Florian. II. Gregorius, H.-R. (Hans-Rolf), 1942-. III. Rudin, Dag. IV. IUFRO
Working Party "Genetic Aspects of Air Pollution." V. IUFRO Working Party "Ecological and Population
Genetics." VI. IUFRO Working Party "Biochemical Genetics." QK751.G381989 582.16'05222 89-11262
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Preface
The present volume reflects the recently increased awareness that air pollutants may
introduce selective effects which endanger the genetic multiplicity of forest tree species. The
communications are based on lectures given at a meeting on "Genetic Effects of Air Pollution
in Forest Tree Populations" held in 1987 in GroBhansdorf (Fed. Rep. Germany) and orga
nized by the working parties "Ecological and Population Genetics", "Geneti~ Aspects of Air
Pollutants", and "Biochemical Genetics" of the International Union of Forest Research Or
ganizations (IUFRO). In accordance their objectives, these working parties covered problems
of general significance, problems directly related to the topic, and methodical aspects.
During the preparation of this volume, it turned out that some of the methods of analysis
and interpretation applied might deserve more explanation in order to be accessible to a wider
audience. To serve this need, in Chapter 1 additional papers are included which refer to basic
methodical aspects of genetic research in forest ecosystems, and which also deal with genetic
implications in non-genetic research. Chapter 2 is dedicated to papers on phenotypic and
genetic variation in response to pollutants, thus describing and analyzing the basis on which
selection can operate. Papers on selection effects of pollutants are then collected in Chapter 3.
To provide means of comparison, particularly with short-lived plants, where selection can be
expected to proceed more rapidly than in forest tree species, this chapter also contains a paper
on Silene cucubalus. Since the selective forces exerted by air pollutants can endanger the
genetic multiplicity of populations and even whole species, a fourth chapter treats problems
of preservation of genetic resources. A concluding paper summarizes the discussions at the
meeting.
In many areas of non-genetic ecological research, the fundamental role played by the
amount and patterns of genetic variation within species in the preservation of their adapt
ability is still largely underestimated. Thus, in view of the global man-made changes caused
by CO increase, apparent tendencies towards recovery of polluted forests from deleterious
2
impacts may just be of a temporal nature, since the genetic changes caused by these impacts
may only in later generations prove to inhibit the persistence and re-establishment of viable
ecosystems. It is hoped that the present collection of papers will help to improve the under
standing of the importance of the genetic consequences of environmental pollution and, in
particular, air pollution.
The editors express their deep appreciation for the excellent work of the reviewers, and they
wish to thank all of those who contributed to the meeting and participated in the preparation
of the proceedings. The help of Sigrid Schmaltz in typesetting the manuscript on the computer
was invaluable.
GroBhansdorf, Gottingen, Umea., December 1988
The editors
Table of Contents
Chapter 1: Methods of sampling and genetic analysis
The attribution of phenotypic variation to genetic or environmental variation
in ecological studies. H.-R. GREGORIUS . . . . . . . . . . . . . . . . . 3
Isoenzymes, indicators of environmental impacts on plants or environmentally
stable gene markers? F. BERGMANN, H.-R. GREGORIUS, F. SCHOLZ 17
Chapter 2: Variation in response to pollutants
Variation in and natural selection for air pollution tolerances in trees.
D.F. KARNOSKY, P.C. BERRANG, F. SCHOLZ, J.P. BENNETT 29
Structure and first results of a research program on ecological genetics of
air pollution effects in Norway spruce. F. SCHOLZ, H. VENNE . . . .. 39
Response of Picea abies (L.) Karst. provenances to aluminum in hydroponics.
TH. GEBUREK, F. SCHOLZ ..................... 55
Variation in needle wax degradation in two silver fir provenances differentiated
by tolerance to air pollution. P. RADDI, C. RINALLO . . . . . . . . .. 67
Natural variation in sensitivity of reproductive processes in some boreal forest
trees to acidity. R.M. Cox ................... . 77
Effects of air pollutants on reproductive processes of poplar (Populus spp.)
and Scots pine (Pinus sylvestris L.).
H. VENNE, F. SCHOLZ, A. VORNWEG 89
Chapter 3: Selection effects of pollutants
Genetic studies in populations of Silene cucubalus occurring on various
polluted and unpolluted areas. J.A.C. VERKLEIJ, W.B. BAST-CRAMER,
P. KOEVOETS . . . . . . . . . . . . . . . . . . . . . . . . .. 107
Studies of Scots pine populations in polluted and clean areas.
L.E. MEJNARTOWICZ, B. PALOWSKI . . . . . . . . . . 115
Genetic implications of environmental stress in adult forest stands of
Fagus sylvatica L .. G. MULLER-STARCK . . . . . . . . . . 127
Selection effects of air pollution in Norway spruce (Picea abies)
populations. F. BERGMANN, F. SCHOLZ. . . . . . . . . . 143
Chapter 4: Preservation of genetic resources
The importance of genetic multiplicity for tolerance of atmospheric
pollution. H.-R. GREGORIUS. . . . . . . . . . . . . . . . . 163
Gene resources and gene conservation in forest trees: General concepts.
M. ZIEHE, H.-R. GREGORIUS, H. GLOCK, H.H. HATTEMER, S. HERZOG 173
Measures for the conservation of forest gene resources in the Federal
Republic of Germany. H.-J. MUHS . . . . . . . . . . . . . . 187
Implications of genetic effects of air pollution on forest ecosystems
- Knowledge gaps - D.F. KARNOSKY, F. SCHOLZ, TH. GEBUREK,
D. RUDIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Contributors
You will find the addresses at the beginning of the respective contribution
BAST-CRAMER, W.B. 107 MEJNARTOWICZ, L.E. 115
BENNETT, J.P. 29 MULLER-STARCK, G. 127
BERGMANN, F. 17,29,143 MUllS, H.-J. 187
BERRANG, P.C. 29 P ALOWSKI, B. 115
Cox, R.M. 77 RADDI, P. 67
GEBUREK, Th. 55,199 RIN ALLO, C. 67
GLOCK, H. 173 RUDIN, D. 199
GREGORIUS, H.-R. 3,17,163,173 SCHOLZ, F. 17,29,39,55,89,143,199
HATTEMER, H.H. 173 VENNE, H. 39,89
HERZOG, S. 173 VERKLEIJ, J.A.C. 107
KARNOSKY, D.F. 29,199 VORNWEG, A. 89
KOEVOETS, P. 107 ZIEHE, M. 173
Chapter 1: Methods of sampling and genetic analysis
The attribution of phenotypic variation to genetic or
environmental variation in ecological studies
HANS-RoLF GREGORIUS
Abteilung fur Forstgenetik und Forstpfianzenziichtung,
Georg-August Universitii.t Gottingen,
Biisgenweg 2, 3400 Gottingen, Fed. Rep. Germany
Abstract: In ecological studies the causal analysis of phenotypic variation in natural popu
lations is frequently based on either environmental or genetic variables only. This situation
requires specially adapted methods of sampling in order to detect environmental or genetic
effects, respectively, on the phenotypic variation. It is demonstrated that simple random
sampling is not an appropriate method since, as a rule, genetic types cannot be assumed to
be distributed at random over environments. A generally applicable alternative is provided
by 'pairwise sampling'. This structured sampling method is based on a decomposition of the
population into subpopulations within each of which random association of genotypes and
environments can reasonably be assumed. The procedure consists in sampling at random
an individual from the total population, and then, given the subpopulation to which this
individual belongs, sampling at random a second individual from the same subpopulation.
It is argued that in many situations sampling of nearest neighbours meets the requirements
of pairwise sampling. Sufficient conditions for inferring genetic or environmental effects,
respectively, on the phenotypic variation are derived.
Introduction
The basic causes to be considered in any analysis of phenotypic variation are of genetic
and/or environmental origin. With particular reference to the theme of the present volume,
namely the effects of air pollutants on forest decline, the necessity to consider both these
classes of causes was emphasized and demonstrated by Scholz (1988). In artificially founded
populations or controlled experiments such an analysis is usually performed with the help of
routine techniques of the analysis of variance, which requires, of course, that both classes of
causes be properly distinguishable in the experimental design.
A completely different situation arises when anaylses of phenotypic variation are to be
conducted in natural populations, in which the prerequisites of standard experimental design
are rarely realized. Moreover, in the vast majority of studies of natural populations, either
of the basic classes of causes, genetic or environmental, is not or cannot be included into the
observations. Hence, the anaylsis of phenotypic variation must rely on finding some type of
correlation either between phenotypes and environmental conditions or between phenotypes
and genetic types. The analysis of these situations is the topic of the present paper.
F. Scholz, H.-R. Gregorius and D. Rudin (Eds.)
Genetic Effects of Air Pollutants in Forest Tree Populations
© Springer-Verlag Berlin Heidelberg 1989
4
According to the above remarks three types of information must be distinguished in
studies of the genetic and/or environmental causes of phenotypic variation in natural popula
tions: (1) both genetic and environmental variables are explicitly included in the observations,
(2) genetic but not environmental variables, and (3) environmental but not genetic variables
are explicitly included. With respect to (1) problems of inference arise in the conventional
analysis of variance if genotypes and environments are not associated at random (which is
likely to be the rule in natural populations), however, such problems can be overcome by the
analysis of norms of reaction (Gregorius 1977, Suzuki et al. 1981, p.821ff and, in particular,
p.824). With respect to (2) and (3), where the detection of either only genetic or only envi
ronmental effects on the phenotypic variation are of concern, neither the analysis of variance
nor the analysis of norms of reaction are applicable since only one of the two basic causal
variables enters into the observations.
Even though the latter situation is very common in ecological studies, as was empha
sized above, its analysis appears still to be largely based on intuitive reasoning rather than
on conceptual rigour. For example, a frequently applied method of analysis of the effects of
an environmental variable on a phenotypic response variable consists in defining a 'control'
environment, within which the phenotypic variation is compared with that of the other en
vironments. If the distribution of phenotypes differs significantly among the environments,
i.e. if stochastic independence of environments and phenotypes is not realized, environmental
effects are inferred to participate in the generation of the phenotypic variation observed in the
population. It is recognized that the correctness of this conclusion may depend to some de
gree upon the mode of distribution of the members of the population over the environments,
yet, an assessment of this uncertainty is usually not made or cannot be made. Because of
the symmetry of the problem, analogous remarks apply to the analysis of genetic effects on
phenotypic variation if environmental factors are not explicitly considered.
Non-random associations among genotypes and environments, which are common in
natural populations, can arise due to various forces with the effect of feigning genetic or
environmental effects on phenotypic variation in random samples of individuals taken from
the total population. For example, strong correlations between phenotypes and environments
can be produced solely by genotypes at gene loci that affect two traits pleiotropically, where
one but not the other of the two traits is under observation. If the trait not under observation
is subject to local adaptations (thus creating non-random distribution of genotypes over
environments), this may imply a non-random distribution of the observed trait over the
environments. Herewith the expression of the observed trait may be completely unaffected
by the environmental conditions in question despite its strong statistical correlation with
these. For two genotypes gl, g2 in two environments C1, C2 this situation can be represented
by the following genotype-environment response function
gl g2
C1 t1 t2
C2 t1 t2
5
where t1 and t2 are the expressions of the trait under observation. Hence, in this example,
the phenotypic differences are solely due to genetic differences. Furthermore, assume that
(as a consequence of differential local adaptations for the non-observable and pleiotropically
controlled trait) within each environment the two genotypes occur in proportions specified in
the following table
gl g2
C1 q1 1-q1
C2 q2 1-q2
Clearly, among all individuals in environment C1, q1 specifies both the proportion of indi
viduals with phenotype t1 and the proportion with genotype gl. Similarly, q2 is both the
proportion of individuals with phenotype t1 and with genotype gl among all individuals in
environment C2. Hence, a study of the effects that the two environments C1 and C2 have on
the phenotypic variation represented by the types t1 and t2 would be concerned with the
estimation of the frequencies q1 and q2 of phenotype t1 in each of the environments C1 and C2.
A significant difference between these two estimates is then usually accepted as a sufficient
indication for the involvement of environmental effects in the phenotypic variation. This erro
neous conclusion emanates from the non-random association of genotypes and environments
implied by q1 f. q2, and it is inevitable as long as the inference is based on a simple random
sample taken from the total population without explicit consideration of the possibility of
the existence of genetic effects.
Analogous criticisms apply, of course, to the use of genotype-phenotype correlations as
means for the detection of genetic effects. Differences in the distribution of genotypes between
phenotypic classes found in random samples taken from a population may be solely due to
environmental effects combined with non-random associations of genotypes and environments.
At the other extreme, random associations of genotypes and environments may as well
complicate the detection of actually existing genetic or/and environmental effects on the
phenotypic variation. Again consider the situation of two genotypes gl, g2 and two envi
ronmental conditions C1, C2, where the phenotype t1 is now realized by both genotype gl
in environment C1 and genotype g2 in environment C2. Similarly, phenotype t2 is realized
by genotype gl in environment C2 and by genotype g2 in environment C1. The deterministic
genotype-environment response function is thus assumed to be as given in the following table:
gl g2
C1 t1 t2
C2 t2 t1
In this example the response functions of the two genotypes are completely different, and
the same is true of the response functions of the two environmental conditions. Hence, both
genetic and environmental effects on the phenotypic variation do indeed exist. Furthermore,
assume that the two genotypes are distributed at random over the two environments and
that equal numbers of individuals are exposed to each environment. Consequently, the dis
tribution of genotypes is the same within each of the two phenotypic classes. Not knowing
the underlying response function, the absence of genetic effects on the phenotypic differences