Reduktion der S02-Immissionen innerhalb des letzten Jahrzehnts (abrupte Regenerationen der S02-empfindlichen

nium Smelter based on the content of fluori

INTERPRETATION UND HYPOTHBSBN Folgende Hypothesen konnen fur die Brklarung der

4. Reduktion der S02-Immissionen innerhalb des letzten Jahrzehnts (abrupte Regenerationen der S02-empfindlichen

Tanne Altersbereich 70

... I

^"'·' Tanne Altersbereich 1 1 0

1 640 1 670 1 900 1 930 1 960 1 990

Jahr

Abbildung: Zeitdiagramme der mittleren Jahrringbreiten (gleitendes Mittel mit Streuungsbandern) for Buchen, Eschen, Fichten und Tannen im Sihlwald bei den physio

logischen Altersbereichen:

1 1 bis 30 Jahre (Altersbereich 30 ), 5 1 bis 70 Jahre (Altersbereich 70) und 9 1 bis 1 1 0 Jahre (Altersbereich 1 1 0).

464

Buchen und Eschen mit verlichteten Kronen (bis SO Prozent Laubverlust) weisen die selben mittleren Jahrringbreiten auf, wie solche ohne Laubverlust. Fichten

mit mehr als 25 Prozent Nadelverlust entwickeln von jeher geringere Jahrringbreiten. Tannen die heute keine oder geringe Nadelverluste zeigen, entwickeln 1 0 bis 20 Jahre nach den massiven Zuwachseinbussen von 1 956, breitere Jahrringe als diejenigen mit grosseren Nadelverlusten, jedoch ohne den zu erwartenden Zuwachs wieder zu erreichen.

Baume mit hOherem Blatt- bzw. Nadelverlust scheinen (bei gleichem physiologischem Alter und von jeher) sensi

tivere Jahrringbreitenkurven zu entwickeln als solche, die heute einen geringeren oder keinen Verlust aufweisen. Die Sensitivitat einer Jahrringkurve gibt an, wie gross die Veranderungen zwischen je zwei sich folgenden Jahrring

breiten sind. Die Sensitivitat ist an okologisch einheitlichen Standorten einerseits ein Mass fur die Anderung der jahrlichen Umweltbedingungen und andererseits ein Mass for die Bmpfindlichkeit des Einzelbaumes.

INTERPRETATION UND HYPOTHBSBN Folgende Hypothesen konnen fur die Brklarung der Zuwachssteigerungen herangezogen bzw. nicht ausgeschlossen werden:

1 . Zunehmend intensivere Bewirtschaftungsformen (Standraumvergrosserung der einzelnen Baume). Der nachenbezogene Volumenzuwachs muss dabei nicht steigen.

2. Bodenregeneration durch die seit der Jahrhundert

wende ausbleibende Streunutzung. Der Bffekt ist mit demjenigen einer Dongung vergleichbar.

3. Dongung durch NOx und C02 aus der Atmosphare. Der flachenbezogene Volumenzuwachs worde dabei steigen.

(Hierbei ist zu beachten, dass durch unkontrollierte Dongung verursachte Zuwachssteigerungen Schaden nach sich ziehen kOnnen wie BrschOpfungssymptome, vorzeitiges Altern der Baume und Stabilitatsverluste der Bestande.)

Die Hypothesen 1., 2. und 3. konnten mit zusatzlichen Studien Ober das Hohenwachstum der Baume OberprOft werden (Standraumvergrosserungen ( 1 .) fuhren gegenober

"Dongungen" (2. und 3.) nicht zur Steigerung des HOhenwachstums).

4. Reduktion der S02-Immissionen innerhalb des letzten Jahrzehnts (abrupte Regenerationen der S02-empfindlichen Tannen).

Zuwachsverminderungen konnen durch samtliche phytotoxisch wirkenden Immissionen entstehen. Im Falle der Zuwachseinbussen der Tannen konnen Obrige, im Zusammenhang mit dem "Tannensterben" diskutierte Hypothesen nicht ausgeschlossen werden.

Systematiscbe Veranderungen eimelner Witterungs

faktoren kommen sowohl fOr die Erklarung von Zuwachs

steigerungen als aucb von Zuwacbseinbussen kaum in Frage:

Die innerhalb dieser Studie als jahrringbreitenbestimmend erkannten WitterungseinflOsse erklaren die Zuwachs

veranderungen im Sihlwald nicht. Ausserdem reagieren verschiedene Baumarten, trotz unterschiedlicben

okologischen Ansprochen, gleichzeitig und in ilhnlicher Art und Weise.

W itterungse1treme konnen aber sehr wohl als Ausloser ror bestimmte Veranderungen im Zuwachsverha^lten wirken: Die massiven Zuwachseinbussen der Tannen werden beispielsweise, wie in weiten Teilen Mitteleuropas, vor allem im Spatfrostjahr 1 956 ausgelost.

Deutlicbe Zusammenhange zwischen Jahrringbild und Kronenzustand konnen nur beschrankt festgestel^lt werden.

Die Scbadendefinition von Nadel- bzw. Blattverlusten muss offensichtlich nach Baumarten und Standorten unter

schieden werden.

Schadigungen oder Regenerationen lassen sich nic^bt im mer gleichzeitig bei Jahrringbild und Kronenzustand feststellen: Aus den Untersuchungen von Kontic und Winkler -Seifert ( 1 986) wissen wir, dass sicb Regener ationen bei T annen, Fic^bten und Fohren, um Jahre froher im Jahrringbild m anifestieren als im Kronenzustaⁿd. Massive W aldscbadigungen kOnnen auch unvermittelt auftreten. Aus Untersuchungen an Buchen (Z'Gr aggen 1 98 6 ) wissen wir, dass diese Bau me eine hohe Resistenz gegenober unterschiedlichen Stressfakto^ren haben und erst nacb Oberscbreiten eines Schwellenwertes innerhalb kurzer Zeit ab sterben.

FOLGERUNGEN

Mit den verwendeten Methoden der Jahrringanalyse und der Kronenansprache konnen nur bedingt Schlosse Ober die Vitalittt der Baume gezogen werden. Blatt- und Nadelverlu

ste kOnnen nur bedingt mit Vitalitatsverlusten und Zu

wachssteiger ungen nur bedingt mit Vitalitatssteiger ungen in Zusammenhang gebracht werden.

Erklarbar wird dies, wenn man bedenkt, dass die in unserer Zeit auf den Wald wirkenden "Storfaktoren " sowohl von wacbstumsfordernder als auch von wachstums

hemmender Wirkung sind. Nicht nur im Sihlwald sondern auch im Obrigen mitteleuropaiscben Raum werden sowohl Zuwacbssteigerungen als auch Zuwacbsreduktionen an unterschiedlicbsten Standorten und bei diversen Baumarten festgestellt (Kontic 1 987).

Die Beobachtungsnetze (Monitoring) des "Waldsterbens"

bezw. der "weitraumig auftretenden Vitalⁱtatseinbussen"

mossen deshalb neu oberdacht und erweitert werden.

Beispielsweise sollte die Beobac^btung weiterer Vitalitats-Merkmale, einheitliche und differenzierte

Erfassungsmethoden der Zwangsnutzungen und die Messung diverser lmmissionskomponenten in die bestehenden Beobachtungsnetze aufgenommen werden.

LITERATUR

Kontic, R., Winkler-Seifert, A., 1 986: Comparitive studies on the annual ring pattern and crown condition of conifers (the Valais, Switzerland ). International Symposium on Ecological Aspects of Tree-Ring Analysis. Palisades, New York.

Z'Graggen, S., 1 986: Die Buchenrindennekrose in Basel und Umgebung. Schweiz. Z. Forstwes., 1 37 ( 1 986) 9: 76 1 -776.

Kontic, R., 1 987: Comparitive studies on the annual ring pattern and crown cond ition of conifers. The situ ation in Switzerland and Southern Germany: General conclusions.

Proceedings of the workshop held in Krakow, Poland:

Forest Decline and Reprod uction: Regional and Global Consequences, I I ASA, 236 1 La1enburg, Austria.

Air Pollution and Forest Decline (J.B. Bucher and I . Bucher-Wallin, eds. ) .

Proc. 1 4th Int. Meeting for Specialists in Air Pollution Effects on Forest Ecosystems, IUFRO P2. 05, Interlaken, Switzerland, Oct. 2-8 , 1 988 . Birmensdorf, 1 989, p. 466-469.

DOSE-DEPENDENT BIOCHEMICAL REACTIONS OF NORWAY SPRUCE TO OZONE FUMIGATION c . Langebart e ls , G . Ffihrer , B . H�ckl , W . Heller , M . Kloos

H . D . Payer , R. Schmit t and H. sandermann, J r . Ins t itut ffir Biochemische Pf lanzenpatho logie

GSF Mfinchen, Ingolstadter Landst r . 1 , D-8042 Neuher berg, F . R . G .

ABSTRACT

Four-year-old plants of Picea abies CL . ) Karst . were exposed t o eight ozone concentrat ions ranging from 0 . 01 to 0 . 8 ppm. The plant s were fumigated for 36 d ( 7 h . d-1 ) in control led environment cham

bers in the fal l of 1987 . Only s l ight chlo

rot ic injury developed dur ing t he fumigat ion per iod . Ozone exposure , however , r esulted in changes in protein band ing pat t erns , and dose-dependent increases were found for pu

t resc ine levels and c innamyl alcohol dehy

drogenase act ivity. The concent rat ion of total as we ll as of several s pec if ic mono

terpenes decreased l inear ly between 0 . 01 and 0 . 6 ppm ozone . On subsequent outdoor culti

vat ion dur ing winter and spr ing in ambient air , the treated plant s deve loped vis i ble symptoms on the previous year ' s need les . The degree of necros is and chlorophyll loss cor

related wit h the o3 dose appl ied . The re

sul ts indicate that ozone fumigat ion leads to several metabo lic changes in Norway spruce , but symptom development may be de

layed unt il the following year . INTRODUCTION

Norway spruce , the dominant forest tree in Central Europe , ranks among t he relat ive

ly ozone-tolerant conifer species (Davis and Wood , 1972 ) , when only vis i b le injury is as

sessed . Exposure to 0 . 07 5 ppm ozone for 48 days resulted in chloros is of t he cur rent year ' s needles and higher concentrat ions led to changes in photosynthesis and t ranspira

t ion (Krause , 1987 ) . In long- term fumiga

t ions over 27 weeks , Kel ler and Has ler ( 1987 ) noted a depress ion of co2 uptake at o. 15 ppm 03 , but observed no signs of vi

s ible injury. Recent ly , there is increas ing informat ion on ' latent ' biochemical effects fol lowing ozone exposure of Norway spruce.

Changes in metabo l i t e pools and enzyme act i

vit ies were found aft er chronic fumigat ion wit h this pol lutant (Bender et al . , 1986 ; Krause , 1987 ; Pel l , 1988 ) .

In the exper iment s reported here , re

act ions of young Norway spruce plants to var ious ozone levels were s tudied in order to determine mechanisms of ozone t oxicity.

The concent rat ions ranged from ambient to acute doses supposed to produce vis ible symptoms . Previous �ose-response studies have been performed wit h forest t r ee species

466

f rom t he United States (Reich, 1987 ) , but informat ion on Norway spruce was not avai

lable . Several biochemical parameters were assayed which may indicate injury or repair processes at t he cel lular level . Delayed effects were recorded af ter post -cul t ivat ion of t he fumigated plant s for ten months under outdoor condit ions . Generat ive and c lone p lants from the same locat ion wer e studied s imultaneous ly in order to compare the degree of var iat ion in response to ozone fumigat ion.

MATERIAL AND METHODS

Clonal stocks of Norway spruce ( c lone 2 9 0 ) and spruce seed l ings , bot h from Schon

gau , Bavaria, were grown under uniform cul

ture condit ions . The plant s wer e pot t ed into a peat /soil mixture nut r if ied wit h a s low

r e l ease fer t i l izer (Plantacote M 8 ) . Four

year-old plant s ( s ix clone and six genera

t ive plants per repl icate ) were t r eated with ozone . Ful l deta i l s of materials and treat

ments wi l l be r epor t ed elsewhere .

Fumigat ion was performed in fall of 1987 in cont ro l led environment chambers ( Payer et al . , 1986 ) . o3 was generated by passing Oz by a UV l ight ozone generator ( F ischer ) and was bled into the f i ltered air s t r eam by mass f low meters . Ozone was ana

lyzed wit h a CSI 1700 analyzer (Messer

Gr ieshe im) . Plants were fumigated for 36 consecut ive days with the fol lowing ozone concent rat ions : f i ltered air ( <0 . 01 ppm;

control ) , 0 , 1 , 0 . 2 , 0 . 3 , 0 . 4 , 0 . 5 , 0 . 6 , and 0 . 8 ( + 5 % ) ppm, 7 h dai ly ( 7 . 30 - 14 . 30 h) . C l imate parameters ( day/night ) wer e : 20/13^°

±. 1 ° c , 60/70 + 5 % R.H. , 13 h photoper iod ( 6 . 00 - 19 . 00 h) , 800 uE . m-2s-1 (max . ; 8 . 00 - 17 . 00 h) , 2 . 5 air changes min-1

Trees wer e sampled direct ly after the o3 t reatment , accommodated to reduced tem

perature and photoper iod wit hin 4 weeks in a greenhouse . Photosynthetic capac ity, chloro

phyll content and needle injury were deter

mined direct ly af ter fumigat ion and after furt her cult ivat ion for 10 months on the previous year • s ( fumigated ) and t he current yea r ' s shoots .

I n vivo pulse label inq. Cur r ent year ' s s hoots from clonal plants were detached and labeled with [ 3 5s ] methionine for 5 h . So

luble needle pro t e ins were extracted in

c i t r ic acid buffer ( pH 2 . 8 ) and separated by SDS polyacrylamide gel electrophoresis followed by autoradiography.

Cinnamyl alcoho l dehydrogenase (CAD) . For biochemical test s , shoots f rom the se

cond and third whorl were harvested and shock frozen in l iquid nit rogen. Needles

we r e str ipped off t he branches under nit ro

gen cooling and then stored at -80^°C . CAD act ivity was measured in need le ext racts using coniferyl alcohol as a subst rate

(Wyrambik and Gr isebach, 197 5 ; modif ied ) . Monoterpenes . Needles wer e homgenized in l iquid nit rogen and were ext racted with pentane . The concentrate was analyzed by cap i l lary gas chromatography ( CP-SiL5 ; 10 m X 0 . 3 2 mm; 3 5 to 250^°C ; FID; N2 l ml min- 1 ) . Hexadecane was added as an

internal standard .

Clone

800

0 600

<...

a. Cl -"'

0 0.2

Q C

0.4 0.6

Ozone 0.8

[ppm]

F ig. 1 Effect of increas ing ozone concentra

t ions on c innamyl alcoho l dehydrogenase ac

t ivity. Data having the same let ter are not s ignif icant ly (P<0 . 05 ) different ( letters for clone 290 plant s are under l ined ) . o-o generat ive Norway spruce ; •-• c lone 290 .

Polyamines . Need les were ext racted with 10% HCl04 and extracts were hydrolyzed with 6 N HCl ( 16 h, 110^°C) . Soluble free and conjugated polyamines were dansylated for 16 h and then separated by r eversed phase HPLC (ODS 5 um; 250 x 4 mm; 6 5 - 9 5 % MeOH;

2 0 min; 1 ml min-1 . Fluorescence emiss ion was measured at 510 nm ( exc itat ion 360 nm) .

Chlorophyl l content . Homogenized needles were ext racted in dimet hylformamide , and chlorophylls a and b were determined by spect rophotomet ry at 646 and 663 nm

(A. Steiger and C . Ltitz , in prep . ) .

Photosynt hetic capac ity per gram dry mat ter at saturat ing co2 pressure and saturat ing l ight condit ions was determined as described (Lange et al . , 1986 ) .

Stat ist ics . Values given are means + S . E . ( n = 6 ) . Response to ozone was analyzed us ing Duncan ' s mult iple range test .

:;,=: 1.0

0, QJ .c VI

!: QJ 0, 0, E

Total monoterpenes Camphene

1 '

^rt

-1

2 - -

-oi-Pinene

f ^Bornyl 0 2 , 6 8 (ppm.10-11

acetat e Borneo!

➔

-ft _Camphor

�

nf"

0 2 � 6 8 0 2 , 6 8 0 2 , & a o z , & 8 0 2 , & 8

Ozone [ ppm • 10-'l ] F ig. 2 Ozone ef fect s on monoterpene .. contents of current year ' s need les of clone p lant s .

RESULTS

Ozone effects immed iately af ter fumigat ion De novo protein synthesis . Pu l s e labe

l i ng of current year ' s shoots of c lone 290 plant s revealed act ive incor porat ion of [ 3 5s ] methionine into proteins in cont rol and ozone- treated plant s _ Exposure to 0 . 4 and 0 . 8 ppm ozone resulted in c hanges in the band ing pat t erns . Protein bands of mole cu lar we ight 16 kD , 23 kD , 50· kD a nd 60 kD

we r e ted plant s and were only s l ight ly vis i ble or prominent in needles of all o3-trea

absent in cont r o l s ( data not shown) .

Cinnamyl alcohol dehydrogenase (CAD> The act ivity of CAD which is invo lved in l ignin biosynt hesis was elevat ed t hree to fourfold at ozone concent rat ions above 0 . 2 ppm (Fig. 1 ) . This increase was s imi lar for c lone and generat ive plants . S i gnificant (P<0 . 05 ) changes were found beginning at 0 . 5 ppm (c lone 290 ) and 0 - 6 ppm ozone (gene rat ive plant s ) , respect ively.

Monoterpenes . The content s o f total monoterpenes and of the dominant compounds camphene , OC-pinene , bornyl acetat e , borneo l and camphene are shown in Fig. 2 . Toget her wit h l imonene ( data not shown) , t hese com

pounds amount t o 70 - 80 % of t he monoter

penes in current year ' s need les of Norway spruce . In need les from clone plant s , cam

phene , o< -pinene , bornyl acetate and borneol as we l l as total monoterpenes ( i nsert of Fig. 1) were decreased by 40 t o 7 0 % when ozone concent rat ions were elevated up to 0 . 6 ppm. Camphor content , on the other hand , was increased by 80 % . Simi lar resu l t s were obtained for generat ive plant s but var iances were markedly higher t han in clone 2 9 0 (data not shown) .

...

600

·.; � l.00

,::.

111 QI L 01

l ___

b ^G_^en_^.

^l

--- ^T

T

^{Clone �}

I �

0 C)

� 200

1/ :

0 0.2 0.4 0.6 0.8

Ozone (ppm) Fig. 3 ozone effects on t he levels of free and conjugated put resc ine in current year ' s need les .

Polyamines . Free and conjugated putres

cine levels were increased 2. 5 ( clone 290 ) to 3 . Sfold ( generat ive spruce ; Fig. 3 ) . In

duct ion was maximal at 0 . 4 ppm ozone and was not further elevated by an ozone dose twice as high ( 0 . 8 ppm; equiv. to 200 ppm. h) . Spermidine levels were · a1so elevated to some extent whi le spermine was unchanged ( data not shown ) .

Ozone effects after post - cult ivat ion

Symptom deve lopment . Exposure t o ozone concent rat ions up to 0 . 8 ppm in fall of 1987 had no signif icant (P<0 . 05 ) effects on pho

t osynthet ic capac ity and chlorophyl l content

X 3

-0 QI C:

>-L ::, 2

g

0 0.2 0.4 0.6

O zon e 0.8 [ppm]

Fig. 4 Effects of ozone fumigat i on in fall on needle injury after subsequent cul ture for ten months . Inser t : \ � rees showing sympt oms of chlorotic mot t l ing .

468

dur ing or d irect ly after the fumigat ion pe

r iod . At this t ime yellowing of needles was observed on less t han 10 \ of t he current year ' s shoot s of the generat ive plants , but not of the c lonal plant s (data not shown) . However , when the t rees were furt her cult i

vat ed outdoors in winter , a l l t rees deve

loped extens ive vis ible symptoms start ing in Apr i l of t he fol lowing year . Uniform brown necrosis on the ( fumigated ) previous year ' s needles increased l inear ly wit h ozone con

cent rat ion in clone 290 and above 0 . 2 ppm ozone in generat ive spruce (Fig. 4 ) . Chloro

t ic needle mot t l ing of these branches was separately assessed and was increased in a l l plant s at ozone concent rat ions above 0 . 3 ppm ( inser t of Fig . 4 ) .

I I I

-I I

0 0.2 O.l

O zon e 0.6

[ppm] 0.8 F iq. 5 Effects of ozone fumigat ion on chloro

phyll a and b content s af ter further cul t i vat ion.

Photosynthet ic capaci ty and chlorophyl l content . Needles which had been exposed to mor e t han 0 . 5 ppm o3 in 1987 showed a decreased photosynt hetic capac ity ( 20 to 40 \ reduct ion) while the newly developed needles from 1988 were not affected ( data not shown) . The dose-dependent decrease of chlorophyl ls a and b in t he previous year ' s needles correlated with needle injury (Fig. 5 ) . The chlorophyl l contents of c lone plants were decreased by 40 \ and t hose of generat ive plants by 50 \ at 0 . 8 ppm ozone compared to controls .

DISCUSS ION

Ozone fumigat ion of Norway spruce led to a number of dose-dependent effects on metabolite levels and enzyme act ivi t ies . Alt ered protein pat terns occurred wit h seve

ral protein bands being induced by t he pol

lutant treatment . These changes in protein biosynthes is as measured by pulse labeling exper iments were detect·ed after f ive weeks of fumigat ion. Long- term exposure to ambient ozone concent rat ions also led to newly syn

t he t ized proteins (R. Schmit t and H. Sander

mann, unpubl . ) or t o changes i n proteins of t he ext racel lular space (Cas t i l lo , 1988 ) .

Cinnamyl alcoho l dehydrogenase act ivity ( CAD) is invo lved in t he synthe s i s of l ignin polymers . CAD ac t ivity was l inear ly in

c r eased 3 - to 4-fold wit h t he po l lutant dose . Ozone may t herefore t r i gger spec i f i c par t s of l ignin biosynt hesis as is t he case for microbial infect ions (Vance et al . , 1980 ) . The cont ent s of mono t e r penes were l inear ly reduced between 0 . 01 and 0 . 6 ppm ozone wi th camphor as one except ion. Clone p lant s showed s ignif icant ly less var iat ion t han generat ive plant s . I t i s unc lear at present whet her t he reduct ion of monoterpene contents may be caused by an increased emiss ion of vo lat i le compounds by t he plant s . Po lyamines have been used a s ind i cators of cel lular repa i r processes f o l lowing seve

ral st ress t r eatment s inc lud ing so2 fumi

gat ion ( Smit h , 1985 ) . Put resc ine and spermi

d ine leve l s in bar ley plant s were e l evat ed by ozone exposure (Rowland et al . , 1988 ) , and an induct ion of free and conjugated put resc ine by ozone was recent ly shown for tobacco (C. Langebar tels , unpub l . ) . In Nor

way spruce , bot h , f ree and conjugat ed put  resc ine leve l s increased and maximum levels were reached at 0 . 4 ppm in generat ive plant s whi le induct ion was not complete at 0 . 8 ppm ozone in c lone 2 9 0 .

Photosynt het ic capac ity and chlorophyll content were not s igni f i cant ly alt ered by t he ozone t r eatments before cul t ivat ion du

r ing winter . Symptoms were f ound on t he previous year s ' s need les fumigat ed in fal l of 1987 . Need le necros is corre lated wi t h t he loss of chlorophyl ls a and b . These data support the view that ( 1 ) Norway spruce p lants wit h ful ly developed need les are re

lat ively tolerant to ozone doses be ing acute ly toxic for young need les .

( I I ) Ce l lular damage which may be mani

fested in the biochemical parameters de

s c r i bed above proceeds dur ing further cul

t ivat ion and leads to highe r sens it ivity against winter f rost or des iccat ion. Frost hardiness of the ozone-t reated t r ees .was r educed by ea. 50 % ( - 3 0^°C f o r controls ; - 15^°C for plant s t r eated wi th 0 . 8 ppm o3 ; Senser and Payer , 1988 ) , but t emperatures dur ing outdoor cult ivat ion did not fal l be l ow the l imi t s even of the fumigated t rees . ( 1 1 1 ) Vis ible symptoms on previous year ' s need les may therefore occur as a re

sult of ozone exposure the year before . This agrees wi th the resul t s of Barnes and Davi

son ( 1988 ) who also found vis i b l e injury in pr evious year ' s needles when Norway spruce p lant s were fumigated wit h 0 . 12 ppm ozone f o r 70 days , rapidly hardened and t hen sub

j ected to f reez ing temperatures between -6^° and -18^°C .

The ear ly biochemical r eac t ions ob

served are cons ist ent wi th t he hypothes is t hat pr ior to vis ible symptoms ozone changes t he phys io logical d i spos it ion of t he plant ( sensu Gaumann , 1 9 5 1 ) to induced resis tance o r pred ispos it ion for subsequent s t resses .

REFERENCES

Barnes , J . D . and A . W . Davison . 1988 . New Phyt o l . 108 : 159-166 .

Bender , J . , H . -J . Jager , G . Seufe r t and u . Ar ndt . 1 9 8 6 . Angew. Botanik 6 0 : 4 6 1-479 .

Cas t i l lo , F . J . 1988 . Proceedings of t he 15th IUFRO meet ing ( t his vo lume ) . Davis , D . D . and F . A . Wood . 1972 . Phyt o

pat ho logy 6 2 : 14-19 .

Gaumann , E . 195 1 . Pf lanz l iche I nfekt i ons

lehr e . Bir khauser , Basel .

Krause , G . H . M. 1987 . In: Air po l lu t i o n and ecosys t ems . P . Mat hy ( ed . ) . D . Re ide l , Dordrecht , pp . 168-2 1 6 . Ke l ler , T . and R . Has ler . 1987 . Trees l :

129-133 .

Lange , o . L . , G . Fuhrer and J . Gebe l . 1986 . Trees l : 7 0-77 .

Payer , H . -D . , L . W . B lank , C . Bos c h , G . Gnat z , W . Schmo l ke and P . Schrame l . 19 8 6 . Wat er Air S o i l Pol lut . 3 1 : 4 8 5- 4 9 1 . Pel l , E . J . 1988 . I n : A i r Po l lut ion and Plant

Metabo l ism. S . Schulte-Hos t ede et al . ( eds . ) . Elsevier , London , pp . 2 2 2- 237 . Re ich, P . B . 1987 . Tree Phys io l . 3 : 6 3 - 9 1 .

Im Dokument Air Pollution and Forest Decline Volume II (Seite 92-98)