21 Technique and Sample Preparation for Plant Tissue D. R. KREGER
Downloaded by TUFTS UNIV on November 22, 2016 | http://pubs.acs.org Publication Date: November 17, 1980 | doi: 10.1021/bk-1980-0141.ch021
Department of Plant Physiology, University of Groningen, Postbus 14, 9750 A A Haren (Gr.), The Netherlands
Methods were discussed to r e v e a l texture in plant materials in situ by X-ray diffraction. A uniform texture i n plant materials is generally confined to areas of microscopic dimensions, and the oriented materials are normally of poor crystallinity. S p e c i a l methods are therefore needed to obtain f i b r e d i f f r a c t i o n from such areas. They may be distinguished as microbeam techniques, artificial orientation of micro-areas, chemical methods improving crystallinity in oriented but poorly crystalline m a t e r i a l s , and combinations of these possibilities. The examples of a p p l i c a t i o n presented were taken from the authors personal experience. They concerned a microbeam technique in which the c o l l i m a t o r s and camera are adapted r e s p e c t i v e l y to produce X-ray beams down to about 10 microns diameter and registration of the diffraction on flat f i l m 10 mm diameter at distances down to 1 mm from the specimen (1, 2). This enabled f i b r e patterns to be obtained from wax coatings on plants (1) and a s i n g l e s t a r c h granule (3), in both instances l e a d i n g to new i n s i g h t s about the u l t r a s t r u c ture of these o b j e c t s . An example of a r t i f i c i a l o r i e n t a t i o n was the o r i e n t a t i o n a t t a i n e d i n c e l l w a l l s of cork t i s s u e by compression, which gives r i s e to o r i e n t a t i o n of the w a l l s i n a plane perpendicular to the d i r e c t i o n of pressure. I r r a d i a t i o n with the beam i n the plane of o r i e n t a t i o n r e s u l t e d i n a f i b r e pattern from which the o r i e n t a t i o n i n the w a l l s of the a l i c y c l i c wax component ( f r i e d e l i n ) could be determined Improvement of f i b r e d i f f r a c t i o n by chemical means was exampled by the r e s u l t s obtained with h y d r o l y t i c and other e x t r a c t i o n s of fungal t i s s u e , i n p a r t i c u l a r with reference to the (l-3)-/# -D-glucan component i n the fibrous m y c e l i a l ropes (rhizomorphs) of A r m i l l a r i a m e l l e a . The rhizomorphs i n the native s t a t e produce only one, oriented but diffuse and weak spacing a t t r i b u t a b l e to ( 1 - 3 ) - - D - g l u c a n . After the adequate chemical e x t r a c t i o n s they y i e l d e d a complete f i b r e 0-8412-0589-2/80/47-141-349$05.00/0 © 1980 American Chemical Society French and Gardner; Fiber Diffraction Methods ACS Symposium Series; American Chemical Society: Washington, DC, 1980.
FIBER DIFFRACTION METHODS 350 pattern o f the glucan. This l e d t o the derivation o f a t r i p l e h e l i c a l structure f o r t h i s g l u c a n c h a i n (j5) i n b o t h t h e h y d r a t e d a n d d r y p o l y m o r p h ( £ , 6), e s s e n t i a l l y s i m i l a r to t h e s t r u c t u r e o f (1-3)-/?-D-xylan (7).
Downloaded by TUFTS UNIV on November 22, 2016 | http://pubs.acs.org Publication Date: November 17, 1980 | doi: 10.1021/bk-1980-0141.ch021
Literature Cited 1. Kreger, D. R . : An X-ray study of waxy coatings from p l a n t s . Rec. Trav. b o t . néerl., 1948, 41, 603-736. 2. Kreger, D. R . : In Bouman, J., E d . "Selected Topics in X-Ray C r y s t a l l o g r a p h y " ; North-Holland P u b l i s h i n g Company: Amsterdam, 1951, p . 340-352. 3. Kreger, D. R.: The c o n f i g u r a t i o n and packing of the chain molecules of native s t a r c h as derived from X-ray d i f f r a c tion of part of a s i n g l e starch g r a i n . Biochim. Biophys. Acta,1951, 6, 406-425. 4. Kreger, D. R.: X-ray diffraction of stopper cork. J. U l t r a s t r u c t u r e R e s . , 1958, 1, 247-248. 5. Jelsma, J.; Kreger, D. R . : U l t r a s t r u c t u r a l observations on (1-3)-β-D-glucan from fungal cell w a l l s . Carbohydrate R e s . , 1975, 43, 200-203. 6. Jelsma, J.: " U l t r a s t r u c t u r e of Glucans in Fungal C e l l W a l l s " ; Thesis, U n i v e r s i t y of Groningen, 1979. 7. A t k i n s , E . D. T . ; Parker, K . D.: The helical s t r u c t u r e of a β-D-1,3-xylan. J. Polymer Sci.: C, 1969, 28, 69-81. RECEIVED May 28,
1980.
French and Gardner; Fiber Diffraction Methods ACS Symposium Series; American Chemical Society: Washington, DC, 1980.
