DISCUSSION AND CONCLUS I ONS

Mean temp.

---

Minimum temperature

adaptation to treatments

···.

.. . .

: _{• •}

. _{_: ··}

_•

.• __ .::··-�=.

. ! :.

'···' \ _, \

_:

.. _.:

\

' _'

- Treatment effects on growt h developed in clone 14 ( p < 0 , 1 t , n = 16 each so i l ) and c lone 1 6 ( p < 1 t , n = 13 ) . Clone 133 showed a s l ight effect only in soil 1 ( p < 5 , 3 t , n = 8 ) .

- ANOVA t r eatment and a l s o between

(p < 5 % ) .

r evea l ed interac t i ons between c lone effects ( p < 5 't) and so i l and c l o ne effects Bes ides o bvi ous inf luences by the s i ngle factors t he stat i s t ical ana lys is also revea led interac t ions between two factors . Special emphas i s has to be g iven to the t reatment effect depending on s o i l condi­ t i ons as we l l as on c lonal character i st ics .

DISCUSSION AND CONCLUS I ONS

For t he f i r s t t ime a long t e rm experi-­

ment last ing mor e t han a year was perfor­ med in c l osed c hambers wi t h forest plant s : Young trees o f Norway spruce were condi­ t ioned for 10 weeks and treated for another 14 mont hs with l ow to med ium leve l s of ozone ( 50 ppb ⁺ event s of up to 170 ppb ) and acid mi s t ( pH 3 ) character istic for a i r pol lut ion at regions of forest decline i n Southern Germany . C l imat i c and fumigat ion cond i t ions , representat ive f o r the Bayerischer Wa ld i n Germany were s imulated and ent i r e ly cont rol­ led in c l imat i c chambers throughout the t reatment per iod .

frost hardening main treatments

.···

. ...

···•···•··· · ..

1986 1987

bud break in bud break

soil 1 soil 2 soil 1 2

-10---+-

^♦

'----'--

⁺

---+---4-lf---'

^{♦__,_♦ ____ --+--I}

\ 1

60 BO 170 110 90 90 80 70 60 ppb•episades of elevated • • • • N••• • • • • • •

ozone treatments

I

periods of lllist events:

+ 1986

• • • • •

60

•

^{60 60}

• •

1987

� 70 BO 70

.... . . _.

⁷⁰

• • • • • • • • • •• • •

80 100 110 120 120 130 90 155 140

• • ■ • • ■ • • • • • •

Time: May June July Aug Sept Oct Nov Dec �an Feb Mar Apr May June July Aug Sept Fig. 1 : Treatment protocol of t he 14-month-exposure of Norway s p ruce to ozone and acid

mist .

508

400 000

ppb • hrs

,:i "'

� Cl) C: 0 N

300 000

°

200 000

100 000

50 000

July Aug ^{Sept Oct} Abscissa: Time ( Months)

Nov Dec ^Jan

Ordinate: Accumulated Ozone loads (concentration •hours)

Chamber 2

/'"···"'

Chamber 3

Feb Mar Apr May June July Aug ^Sept

Fig . 2 : Ozone loads appl ied to t he dupl i cate t reatment and cont r o l groups of Norway s pruce exposed in four environmenta l chamber s for 14 months to ozone and acid mist .

The appl icat ion of 5 different c lones of No rway spruce adapted to two d i f ferent so i l s revea led the impor tance of genet ic factors as wel l as of envi ronmental fac t o r s . The dif ferent c lones exposed d i d not behave a l l the same ; only two to three out of f ive c lones were inf luenced by the exper imenta l a i r po l lut ion. This ind i cates a genet ic d i s ­ pos it ion o f the plant s wi t h regard to t heir suscept ibi 1 i ty to ozone and acid mist . Fur­

t hermore, there are interact ions between s o i l factors and po l lut ion ef fect s i nd ica­

t i ng environmenta l d i spos i t ions of t he p lant s . The resu l t s may help t o under s tand t he wide var iety of t ree dec l ine wi thin t he same canopy , where s o i l and genet ic d is po s i ­ t ions a r e supposed to cont r i bute t o ind i vi­

dua l dif ferences f rom tree to t ree wi t h re­

s pec t to their degree of damage.

The exper ience f rom this i nves t igat ion does not only po int out the s ignif i cance of longterm/ low- level t reatment s yield ing chro­

nic effects , but also the impor t ance of s o i l and genet ic factors which may determine t he s uscept ibil ity of Norway s pruce to a i r po l l ­ u t ion.

REFERENCES

Forschungs bei rat Wa ldschaden/Luftverunreini­

gungen der Bundesregierung , 2 . Ber icht , KfK Kar lsruhe, Mai 1986

Payer , H . D . , Blank , L .W . , Bosch, c . • Gnat z , G . , Schmo l ke, W . , Schramel , P . ( 19 8 6 ) : Water , Air , and So i l Po l l . ll, 4 8 5 - 4 9 1 Rehfuess , K . E . und Bosch, c . ( 19 8 6 ) : For s tw .

Cbl . 105 , 201-2 0 6

3.8 mm 3.4

3.0

� 2.6

-a

g_ ^2.2

,. ..

Cl) C:

2.2 2.6

Control plants

15/1

I ----

_14� ^14/2

1111

7�

^l

7 ^---i

_{• I} ^16/2

133/2

l I

16/1

3.0 3.4 mm 3.8

F i g . 3 : Growt h of Norway s pruce measured as inc rease of s t em width dur ing 14 months of exposure to ozone and acid mi s t : relat ion between t reated and cont r o l plant s . The 4 5^° angle l ine ind i cates t he no-effec t-level ; data wel l below t h i s l i ne indicate a growt h reduct ion by elevated loads of ozone. Clone/

s o i l number s are given for ident i f icat ion.

Bar s represent standard er ror s .

ACKNOWLEDGEMENTS

The technical cont r i but ions of D . Art­ hofer , W. Krat z l , G . Masur , J . Schock , R . Strobel , L . Weichinger , M. Z i s t ler are highly acknowledged . We are also gratefu l to Dr . G . Gnatz , Dr .

w.

Lehmacher , and W. Schmo l ke for extended sc ient i f i c suppo r t .

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

Proc. 14th Int. Meeting for Specialists in Air Pollution Effects on Forest Ecosystems, IUFRO P2.05, Interlaken, Switzerland, Oct. 2-8, 1988. Birmensdorf, 1989, p. 510-512.

PINE NEEDLE ULTRASTRUCTURE IN AN ACID RAIN TREATMENT Jaana Reinikainen and Satu Huttunen

Department of Botany , University of Oulu SF- 9 0 5 70 Oulu , Finl and

ABSTRACT

The ul trastructure of Scots pine ( Pinus sylvestris ) needles was examined in connection wi th an acid r ain experiment undertaken at Kevo resear ch stat ion in northern Finland dur ing the year s 1 986-1 9 8 7. The exper imen t included pH 3 , pH 4 , clean water and dry con trol treatments. The samples were col lected in May 1 9 8 6 , July 1 9 8 7 and October 1 98 7. The mesophy l l t i s sue of the needles treated with acid rain was seen to be partially disinte­

grated , espec ial ly near the hypodermis. Some al ter ations were al so observed in the phl oem.

The size of the mesophyll chl oropl asts varied considerabl y between the different needle years and on the differen t sampl ing dates , due to the s t ar ch grains which accumulate during summer , and which can as much as dou­

ble the s i z e of the chl oropl asts. The dry control and the pH 3 treated needles almost always exhibi ted the smal lest chloroplasts.

The dif ference between summer and autumn w as smal lest in the pH 3 and pH 4 needles , which may be l inked to their decreased abil ity to accumul ate s tarch in summer. The increase of lipid mater i al over the course of the time was evident in al l samples , and especial ly obvious in the acid rain treated needles.

I NTRODUCTION

The vegetat ion in northern areas is nat­

urally influenced by numerous biotic and abiotic factor s , and since air pol lutants nowadays provide an addit ional stress to the ecosystem , they c an lead to severe damage to , and change in , vegetation. During the most recen t year s the rainwater pH in nor thernmost Finland has been on average 4. 7 , and !2e yearly sulphur deposition 0.4-0.8 g m

( monthly reports of the Finnish Meteor ­ ological Institute 1 985-8 7 ) . These values can be considered to be well wi thin the range of values which induce long-term pol lution effects in the sensit i ve northern Finnish forests.

Conifers have been subjects of intens i ve research in central Europe , where the indi ­ cative value o f needle damage h a s been e valu­

ated in respe c t of the forest decline syndrome ( Fink 1 9 8 8 ) . Nevertheless , the ef fec ts of acid rain on the needle ultrastruc ture have not been spec if ied. The effect might be indirec t , resul ting from a disturbance in the nutrient bal ance , or the direc t effect of acidic water penetrat ing through the cut icle and stomata.

Acid rain has been obser ved to c ause a dec l ine in the survival rate ( Percy 1 9 8 6 ) and a

dimin i shing of the rate of photosynthesi s ( Nygren & al. 1 9 8 7 ) of conifer seedl ings.

Also , the leaching of nutrients from fol i age has been obser ved to result from exposure to acid fog ( Mengel & al. 1 9 8 7 ).

510

MATERIAL AND METHCDS

The acid rain treatment was performed in the Kevo Subarctic Re search Institute ,

northern Finl and ( subal pine bir ch forest re­

g ion where some i sol ated pine forests can al so be found ). The spr aying of acidi c wa ter was begun in August 1 9 85 , and continued during the fol lowing summers. Mature pine trees were spr ayed wi th acidif ied water ( H 2so4 : HN01=2 : l ) three times a week. The addit ional sulp��r loads during the exposure were ii 9 . mg m in the pH 3 treatmen t and 0.8 mg m in the pH 4 t�

2

atment , and t�z nitrogen loads were 1.7 mg m and 0.3 mg m , respectively.

Needles f rom the exposed trees were col­

lected and cut into the pr efixat ion media ( glutaraldehyde in pho sphate buffer : pH 7.0 ; 0.0 5 or 0 . 1 M ) . They were transported in a cold bag in to the l abor atory , where the post­

f ixat ion , dehydrat ion and embedding took place. Slices from the middle of the needle

( three needles per sampl e ) were t aken for l ight and elec tron microscopical examinat ions.

RESULTS

The most bad ly in jur ed mesophyl l cells were situated near the hypodermis ( Fig. l a , b ) . The injury wa s seen as a di sintegrat ing of the cells , as we l l as the total col lapse and pl asmolysi s of some cel ls. Some minor al terat ions were al so obser ved in the phloem

( Fig. le , d ) .

Figure l a. May - 8 6 , a pH 3 treated needle from the needle year 1 9 8 5. The mesophyl l tissue is intact , as wel l as the phloem and transfusion parenchyma. bar = 1 0 0 pm

Figur e l b. Oc tober -8 7 , a pH 3 treated needle from the needle year 1 98 5 . The mesophyll has disintegrated espec ial ly near the hypodermis

( H ) . bar = 100 pm , MP = mesophyll , EP = epidermis , HY = hypodermis , EN = endodermis , RD = re sin duc t , PH = phl oem , XY = xylem.

Figure l e. October -8 7 , a dry con trol needle f rom the needle year 1 9 8 5. The phl oem and xylem ar e in tac t and clear ly discernibl e . bar = 5 0 pm .

Figure ld. October -8 7 , a pH 3 treated needle f rom the needle year 1 9 8 5. The phl oem cel l s are con trac ted and poor ly discernible ( H i . Some dark stained mater ial i s accumul at ing into the cells. bar = 50 pm .

XY = xylem , PH = phl oem , A = album inous cell The si ze of the mesophy l l chloropl asts varied consider ably according to the dif­

f erent sampl ing dates . The largest chloropl asts were obser ved in July and a dramat ic change was vi sibl e when compar ing these wi th tho se of the May and October sampl e s ( Fig . 2) . Thi s i s due to t h e huge st arch grains , which accu­

mul ate during the summer and which c an as much as doubl e the volume of the chloropl ast s

( Fig. 3 a , b ) . The difference in the s i ze of the mesophyll chl or opl asts in tho se treated wi th ac id rain compared to the control trees wa s clear on al l sampl ing dates. The dry control and the pH 3 treated needles had the smal lest chl oropl ast s in almost every case . The youngest needles f rom the pH 4 and pH 3 treated trees showed the least difference in chl oropl ast si ze between summer and autumn.

This m ight be due to a decreased abil ity in the young chloroplasts to accumulate star ch when be ing irrigated with ac id rain .

□ m

J'tlLY 1887

■

OCTOBER 1987

DRY WJLTEJI pB<II pH 3 IGM NBEDLBS

Figure 2. The chl oroplast area (pm²) in dif­

f erent sampl ing dates and treatments in needle year s 1 98 5 , 1 9 8 6 and 1 9 8 7 . Dif ferences be ­ tween sampl ing dates are signif ic ant in al l but the youngest needle year in pH 3 and pH 4 treatments . var iat ion in the chloropl ast area between dif f erent needle year s i s al so signi­

ficant ( tests performed with ANOVA procedure ) .

Figure 3 a . May -8 6 , a pH 4 treated needle from the needle year 1 9 8 5. The star ch grains are smal l and chloropl ast shape regular. balr = 1 µm . Figure 3 b . July -8 7 , a dry control needle from the needle year 1 986 . Large starch grains have been accumulat ing in to the chloropl ast s . bar = 5 µm .

ST = s t arch , CH = chloropl ast , TA = t annin , N = nucleus , L = l i pid droplet .

A prom inen t ultrastruc tural feature ob­

served in the experiment was the incre ase and accumul at i on of lipid material ( Fig . 4 a , b ) . The amount of lipids was lowe st on the first sampl ing date , after which accumulations in­

creased continuously . In July consider abl e amoun ts of l i pids were seen surrounding and even in side the chloroplast s . The olde st needles had the greatest amount of lipids in their mesophy l l cells . In the pH 4 and pH 3 treated needles espec ially some lipid granules were seen accumulating between the pl asma membr ane and the cell wal l . Some dark-s t a ined mater ial wa s al so observed accumulat ing in the cytopl asm of the pH 3 and pH 4 exposed

needles .

Figure 4 a . October -8 7 , a dry con trol needle from the needle year 1 9 8 5 . Some lipid droplets have accumulated into t he cytoplasm during the hardening per i od . bar = 1 µm.

Figure 4 b . October - 8 7 , a pH 3 treated needle from the needle year 1 9 8 5 . Large areas of lipid mater ial appe ar in the cytopl asm . bar = 1 µm .

CH = chl or opl ast , N = nuc l eu s , M = mitochondri a , L = l ipid .

DI SCUSSION

The m ain target of the effects of air pol lutan ts is the mesophy l l t i s sue , where the ac tive met abol ic reaction s t ake pl ace . Ex­

po sure t o ac id rain was seen to af fect the mesophyll in part icular , although some consequences of thi s expo sure were vi sibl e al so in the transfusion t i s sue , and these c an be expl ained by indirec t effects on the nu­

trient bal ance . The exten t of the area of mesophy l l chl oropl asts c an be relat ed to photosynthe t ic ef ficiency , and is greatly inf luenced by envir onmen tal condit ions . The smal ler var iat ion of si ze of the chloroplast areas in the pH 3 and pH 4 treated need les from summer to autumn could indicate a sl ight ly decreased abi l ity t o assimil ate st arch dur ing summer t ime . Also the accumu­

lat ion of l ipid dropl e t s into the cytopl asm may be an effect of ac id r ain , even though it is al so a c onsequence of the ageing of the needles .

SUMMARY

The effects of ac id r a in on pine needle ultrastruc ture were obser vabl e in slightly disintegrated tran sfusion t i s sues , al terat ions in the mesophy l l chlor opl ast area and an increase of l i pid mater i al in the cells .

REFERENCES

Fink , S . 1 9 88 . Patho l og ic al anatomy to conifer needles subjec ted to gaseous air pol­

lutants or mineral def ic iencie s . in press in Aqu i la Ser Botanic a .

Mengel , K . , M . Th . Brein iger , and H . J . Lu t z .

512

1 98 7 . Effect of ac id fog on nutrien t leaching and needle condition o f P icea abies . I n : Proc . of a work shop jointly organ i sed by the CEC , the Swedish Univ . of Agricultural Sciences and the

Institute of Environmental Research , Lokeberg , 19-23 Oct . 1 9 8 6 . Direct effects of dry and wet depo s i tion on forest ecosy stems - in part icular canopy in terac t ions .

Nygren , P . , P . Hari , and E . Kor pi l aht i . 1 9 8 7 . The in teractive effec t of po tassium defic it and ac id water on photosynthe s i s o f Scot s pine seedlings . In : Acid Rain : Scientif ic and technical advances , ed . by R . Perry , R . M . Harrison , J . N . B . Bel l , J . N . Le ster . Publicat i ons Di vi sion , Sel per Ltd , London .

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. 51 3.

VISUALLY ESTIMATED DEFOLIATION CLASS VS . OTHER CONDITION

Im Dokument Air Pollution and Forest Decline Volume II (Seite 136-141)