ELECTRON MICROPROBE ANALYSIS OF SOUND AND PITTED TISSUES OF APPLE FRUIT AFFECTED WITH BITTER PIT

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ELECTRON MICROPROBE ANALYSIS OF SOUND AND PITTED TISSUES OF APPLE FRUIT

AFFECTED WITH BITTER PIT

A. Chamel, P. Bondoux, J. Bossy

To cite this version:

A. Chamel, P. Bondoux, J. Bossy. ELECTRON MICROPROBE ANALYSIS OF SOUND AND PITTED TISSUES OF APPLE FRUIT AFFECTED WITH BITTER PIT. Journal de Physique Colloques, 1984, 45 (C2), pp.C2-499-C2-501. �10.1051/jphyscol:19842113�. �jpa-00223781�

JOURNAL DE PHYSIQUE

Colloque C2, suppl6men.t au n02, Tome 45, f6vrier 1984 page C2-499

ELECTRON MICROPROBE ANALYSIS OF SOUND AND P I T T E D TISSUES OF APPLE F R U I T AFFECTED WITH B I T T E R P I T

A. Charnel, P . Bondoux* and J.P. Bossy

Laboratoire de BioZogie Ve'ge'taZe, De'partement de Reekerehe Fondamentale, Centre dfEtudes NueZdaires, 85 X, 38041 GrenobZe Cedex, Frmee

* s t a t i o n de PathoZogie Ve'ge'taZe, I.N.R.A., Beaueouze', 49000 Angers, France

Resum& - Les concentrations de K, Ca, Mg, P, S e t C1 o n t & t & compar@es dans l e s t i s s u s sains e t malades de 5 v a r i & t @ s de pommes, a t t e i n t e s de b i t t e r p i t . Mg, Ca e t a un moindre degre S e t a i e n t presents a des concentrations plus elev&es dans l e s zones malades par r a p p o r t aux zones saines. Les r e - s u l t a t s concernant l e s a u t r e s elements e t a i e n t v a r i a b l e s e t dependaient de l a v a r i @ t & .

A b s t r a c t - The concentrations o f t h e mineral elements K, Ca, Mg, P, S and C1 have been compared i n p i t t e d and sound t i s s u e s o f mature f r u i t s o f f i v e

apple c u l t i v a r s . Mg, Ca and t o a l e s s e r e x t e n t S a r e present i n h i g h e r con- c e n t r a t i o n s i n p i t t e d areas than i n n o n - p i t t e d ones. The r e s u l t s concer- n i n g t h e o t h e r elements vary and depend on t h e c u l t i v a r .

An e l e c t r o n microprobe was used t o compare the contents i n K, Ca, Mg, P, S and C1 of t h e p i t t e d and sound t i s s u e s of apple f r u i t s affected by p h y s i o l o g i c a l d i s o r d e r s ( b i t -

t e r p i t o r l e n t i c e l b l o t c h p i t ) (Chamel and Bossy (198l)). Small s l i c e s of mature f r u i t s s u p p l i e d by the P l a n t Pathology S t a t i o n o f Angers and containing b o t h sound and p i t t e d areas have been r a p i d l y excised and immediately frozen i n f r e o n 22 cooled w i t h l i q u i d n i t r o g e n then f i x e d w i t h Tissue Tek I1 O.C.T. (Lab. Tek. Products) on t h e p l a s t i c h o l d e r o f t h e microprobe, so as t o a l l o w surface a n a l y s i s along l i n e s c r o s s i n g e i t h e r sound o r p i t t e d areas, from the s k i n towards i n t e r n a l t i s s u e s . The samples t o be analysed have been smoothed i n a cryotom (model HRLM-SLEE, London), f r e e z e d r i e d i n a V i r t i s (model 10-010 TD) apparatus f o r 2 days a t -40°C and s t o r e d i n a d e s i c c a t o r u n t i l a n a l y s i s .

The same analyses have been c a r r i e d o u t d i r e c t l y on f r e s h m a t e r i a l .

Other analyses have been performed w i t h an e l e c t r o n microprobe CAMEBAX (CAMECA- France). They have been c a r r i e d o u t on samples coated w i t h aluminium on spots o f 37,5 x 37,5 urn2, along l i n e s extending from t h e sound o r p i t t e d f r u i t s k i n towards sound i n t e r n a l t i s s u e s , w i t h a step v a r y i n g from 150 t o 700 pm. Only p i t t e d areas i n which t h e c e l l w a l l s were apparently s t i l l i n t a c t have been analysed. C h a r a c t e r i s t i c

X-rays were recorded using a TAP c r y s t a l f o r Mg and P and a PET c r y s t a l f o r K, Ca, S

and C1 under the f o l l o w i n g c o n d i t i o n s : a c c e l e r a t i n g voltage, 10 Kev ; sample cur- r e n t i n t e n s i t y , 10 rrA ; m a g n i f i c a t i o n , 800 ; a n a l y s i s time, 20 s. For each sample, 3-9 a n a l y s i s axes have been considered, w i t h a t l e a s t 10 measurements along each.

The background values measured f o r each element near t h e peaks under c o n s i d e r a t i o n have been deducted from the values of t h e corresponding peak i n t e n s i t i e s . Compari- sons between sound and p i t t e d areas i n a given s l i c e have been e f f e c t e d w i t h t h e n e t p e a k - i n t e n s i t y values u s i n g t h e non-parametric Mann-Whitney U - t e s t (Sokal and Rohlf (1969)).

Results

V a r i a t i o n s i n t h e mineral contents between p i t t e d and n o n - p i t t e d areas have shown t o be depending on t h e element and on t h e c u l t i v a r (Tablie 1 ) .

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19842113

C2-500 JOURNAL DE PHYSlQUE

T a b l e 1 : Comparisons o f m i n e r a l c o n t e n t s between p i t t e d and sound areas ( t h e values correspond t o t h e r a t i o average i n t e n s i t y i n t h e p i t t e d area/average i n t e n s i t y I n t h e sound a r e a ) .

. ¹ t o 3 samples have been analyzed f o r each c u l t i v a r .

.

.

Cul t i v a r Elements

: K : C a : M g P S : c 1 :

-- --

: Akane.. ... ^{: 1.3 : 5.3::::} : 14.0:::: : 2.5:: : 2.8:: : 2.5:: : 1.3:: : 7.9::::: 12.8::::: 2.3::::: 2.4::::: 0.9 : : Re.ine des R e i n e t t e s . . . . .

: I d a r e d ... : 0.7:: : 3.4::::: 3.1::::: 0.9 : 3.1::::: 0.4:::::

: Granny Smith..

...

The c o n t e n t s o f Mg, Ca and S were always s i g n i f i c a n t l y h i g h e r i n p i t t e d t h a n i n non- p i t t e d t i s s u e s f o r t h e s t u d i e d c u l t i v a r s w i t h t h e e x c e p t i o n o f Ca i n Granny Smith.

The o t h e r considered elements were a l s o a f f e c t e d , b u t t h e r e s u l t s v a r y and depend on t h e c u l ti v a r .

I t s h o u l d be n o t e d t h a t analyses c a r r i e d o u t d i r e c t l y on f r e s h m a t e r i a l have g i v e n r e s u l t s s i m i l a r t o t h o s e o b t a i n e d w i t h f r e e z e d r i e d samples.

Recent analyses have been made on apple f r u i t s (Merton Knave), t h a t had been submit- t e d b e f o r e t h e h a r v e s t , t o t r e a t m e n t s w i t h 1 % SOqHg, which r e s u l t e d i n an i n c r e a s e o f t h e symptoms o f b i t t e r p i t (Bondoux e t Charnel ( u n p u b l i s h e d ) ) . The comparison bet- ween sound and p i t t e d t i s s u e s o f t h i s c u l t i v a r has c o r r o b o r a t e d t h e g r e a t e r Mg and Ca c o n t e n t s i n t h e p i t t e d areas ( T a b l e 2), b u t a l s o r e v e a l e d t h e i m p o r t a n t s u p e r f i - c i a l l o c a l i z a t i o n o f Mg i n t h e sound p a r t and a maximum c o n c e n t r a t i o n o f t h i s element i n t h e m i d d l e o f t h e p i t t e d area.

Table 2 : Comparisons o f Mg and Ca c o n t e n t s ( n e t peak i n t e n s i t i e s ) between p i t t e d Z d T E i n d areas, w i t h t h e c u l t i v a r Merton Knave.

.

Sound t i s s u e : P i t t e d t i s s u e

: D i s t a n c e f r o m t h e s u r f a c e :

(mm)

The v a r i a t i o n s observed u s i n g t h e e l e c t r o n microprobe i n t h e m i n e r a l c o n t e n t s o f t h e p i t t e d t i s s u e s add t o p r e v i o u s r e s u l t s ( P e r r i n g and P l o c h a r s k i (1975) ; H o p f i n g e r and Poovaiah (1979) ; Meyer e t a l . ( 1 9 7 9 ) ) . They suggest t h a t i m p o r t a n t p h y s i o l o g i c a l d i s o r d e r s o f f r u i t s such as b i t t e r - p i t i n apples a r e a s s o c i a t e d w i t h e x t e n s i v e n u t r i t i v e p e r t u r b a t i o n s a f f e c t i n g t h e i o n i c exchanges and consequently t h e c e l l u l a r p h y s i o l o g y .

References :

1. CHAMEL A., BOSSY J.P., S c i e n t i a H o r t i c .

15

2. HOPFINGER J.A., POOVAIAH B.W., Commun. S o i l S c i . P l a n t Anal. 10 (1979) 57-65.

3. MEYER B.R., PEISACH M., KOTZE W.A.G., S c i e n t i a H o r t i c - l O (1979) 57-61.

4. PERRING M.A., PLOCHARSKI W., J. S c i . Food A g r i c . - 26 (1975) 1819-23.

5. SOKAL R.R., ROHLF F.J., Biometry. The P r i n c i p l e s and P r a c t i c e o f S t a t i s t i c s i n B i o l o g i c a l Research (Freeman, San F r a n c i s c o ) 1969, p. 392.