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Chromosome individuality and somatic pairing in Abies grandis Campbell, John Duncan 1949

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CHROMOSOME INDIVIDUALITY AND SOMATIC  PAIRING  IN Abies  grandis  J o h n Duncan  A Thesis the  Campbell  submitted i n p a r t i a l  fulfilment of  requirements f o r t h e degree o f MASTER  In  OP ARTS  t h e Department of  BIOLOGY a n d BOTANY  The U n i v e r s i t y  of British  April,  1949  Columbia  Chromosome I n d i v i d u a l i t y and in Abies by University  British  Pairing  grandis  J o h n Duncan  of  Somatic  Campbell  Columbia,  April,  1949  Abstract One studies  of  the  phenomena u n c o v e r e d  of Abies  grandis  LIndley,  the  existence of  pairing  of  the  v e r y young o v u l e s .  pairing  i s not  rare  properly recorded. study of the  the  the  in  cytological  Lowland White F i r ,  chromosomes i n s o m a t i c  Huskins  (1948) has  plant  I t was  thought n e c e s s a r y  morphology of  the  world, but  Individual  cells  shown t h a t  i n the  is  was of  somatic  seldom  to u n d e r t a k e  chromosomes  a  of  tree.  C o u n t s and  measurements were made on  the  chromosomes  r  in  several  cells,  percentage of  and  the  total  Positions  of  were a l s o  tentatively  The  the  lengths of  the  3,  10.6$  units;  7,  8.1# 5,5%  shaped  units;  chromosome l e n g t h  4, 8,  located  attachments or and  9.6$ 1,2%  12,  3.3$  ends w i t h o u t any  14.4$  r e c o r d e d as  units  units; units;  5, 9,  units.  long; 9.1$  6.4$ Two  constriction,  to  i n the  t w e l v e chromosomes i n t h e  Chromosome 1,  11,  measurements r e d u c e d  spindle-fibre  follows:  units;  the  2,  cell.  centromeres percentages. genome a r e  11.3$  units; units;  a  as  units;  6,  8.4$  units;  10,  6,1%  units;  chromosomes h a v e w h i l e f i v e have  clubsingle  - 2 -  t e r m i n a l knobs. and  One h a s t h r e e c o n s t r i c t i o n s ,  f o u r have b u t a s i n g l e  dicentric,  four are approximately  d i s t i n c t l y heteromeral,  Somatic pairing  that  cells  o f chromatin  examined. and  I t i s thought  isomeral, f i v e are  a n d two h a v e t e r m i n a l  studied,  the pairing  between c h r o m a t i n  apparent  t o be i n d i c a t i o n  i s so d i s t i n c t  threads  so s t r i k i n g  o f some s o r t o f r e d u c e d  The d i f f e r e n c e s between s o m a t i c  somatic  centromeres.  f r o m young o v u l e s showing  m e i o s i s a r e d i s c u s s e d and a l s o for  One chromosome i s  s t r a n d s a t e a r l y a n a p h a s e were  I n one c e l l  the s i m i l a r i t y  meiosis.  constriction.  one h a s two,  pairing  some t h e o r i e s  and t r u e  on t h e r e a s o n  pairing.  Some p r o b l e m s i n t e c h n i q u e o f c o n i f e r c y t o l o g y a n d t h e methods u s e d  i n this  study a r e s e t f o r t h .  Table o f Contents  I II III IV V VI  Introduction  1  Literature  1  Materials  a n d Methods  5  Chromosome M o r p h o l o g y  7  Somatic  Pairing  13  Discussion  VII  Appendix  VIII  Summary  - Cytological  Literature Table of  14 Technique  17 21  Cited Plates  A c k n o w l e d g emen t 3  I would l i k e o f f e r e d me Biology  by  and  Dr.  to  A.H.  Hutchinson of  Botany, U n i v e r s i t y  study of  t h i s problem.  material  and  store  Forestry, Brink of Columbia. am  deeply  He  the  h e l p f r o m Dr. University the To  of  G.S.  also  British  Department  of  Columbia,  in  s u g g e s t i o n s and  subject.  I have a l s o  A l l e n of  British  Department o f  of  the  incalculable  made a v a i l a b l e t o me  equipment, but  o f k n o w l e d g e on  valuable  acknowledge the  the  C o l u m b i a , and  to the  Campbell.  the  only vast  received of  f r o m Dr.  University  indebted.  J o h n D.  a  Department  Agronomy, U n i v e r s i t y  t h e s e p e o p l e and  not  help  of  V.C.  British  itself,  I  I  As coniferous  Introduction  p a r t o f t h e p r o g r a m o f c y t o l o g i c a l r e s e a r c h on trees proceeding  University of British was made o f v a r i o u s  u n d e r D r . A.H. H u t c h i n s o n a t t h e  Columbia, m i c r o s c o p i c a l  stages  Lowland White F i r , Abies  i n the reproductive  grandis  t i s s u e o f the maturing ovule  Lindley.  and  c y c l e o f the  I n the somatic  were s e e n a t l e a s t  d i v i s i o n s which appeared t o resemble m e i o s i s they  examination  a few c e l l  i n many ways;  seemed t o c o n t a i n p a i r e d chromosomes a t t h e m e t a p h a s e anaphase.  nature  I t was r e a l i z e d  o f these  t h a t any i n v e s t i g a t i o n o f t h e  d i v i s i o n s would r e q u i r e p r e c i s e  identification  o f t h e I n d i v i d u a l chromosomes i n t h e genome b y t h e i r morphological  appearance.  This  study  attempts to d e s c r i b e  i n a p r e l i m i n a r y way, t h e m o r p h o l o g y o f t h e chromosomes o f Abies  grandis  as w e l l as t h e i r apparent p a i r i n g .  II  Hutchinson i n Abies  Literature  (1915) i n a d e t a i l e d a c c o u n t  balsamea d e s c r i b e d  the p a i r i n g o f p a t e r n a l and  m a t e r n a l chromosomes, a n d t w i s t i n g o f t h e p a i r s , f o l l o w e d by t r a n s v e r s e  splitting  ant  d a u g h t e r chromosomes  and  Haupt  o f syngamy  and m i g r a t i o n  to the opposite  (1941) w o r k i n g on P i n u s  failed  poles.  a t syngamy,  o f the r e s u l t Beal  to confirm  (1934)  this, but  - 2 -  Chamberlain Allen  (1935) commenting o n t h e c y c a d S t a n g e r i a a n d  (1946) w o r k i n g  on P s e u d o t s u g a  e m b r y o l o g i c a l phenomena be  of their  both  suggest  r e s p e c t i v e genera  e x p l a i n e d by the o c c u r r e n c e o f post-syngamic  With regard to true meiosis i n Abies, (1945) w o r k i n g  on t h e m i c r o s p o r o g e n e s i s  that, while c e r t a i n heterochromatin  Recent Kodani be  can best  pairing.  Rattenbury  o f A, g r a n d i s  found  a l l the normal  s t a g e s were p r e s e n t i n a r e c o g n i z a b l e f o r m .  work u n d e r H u s k i n s  a t Wisconsin  (Huskins  1948,  1948) h a s shown t h a t p a i r i n g a n d even s e g r e g a t i o n c a n  induced i n somatic  m i t o s i s by treatment  salt of ribose nucleic large l i s t to  certain  d e t a i l s o f n u c l e o l u s development and  t r a n s f e r were p e c u l i a r ,  prophase p a i r i n g  that  Besides  of references giving  show t h a t n a t u r a l  of course,  acid.  the well  somatic  this,  Huskins  cites  a  evidence o f v a r y i n g c e r t a i n t y  pairing  established fact  chromosomes i n t h e s a l i v a r y g l a n d s Dipteran f l i e s ,  w i t h the sodium  can e x i s t ; he that  includes,  the giant  o f D r o s o p h i l a and o t h e r  are r e a l l y pairs of very c l o s e l y  synapsed  h o m o l o g o u s chromosomes.  One o f t h e b e s t d i s c u s s i o n s o n chromosome in  C o n i f e r s i s contained i n the paper  These workers determined of Conifers, relative the  morphology  b y Sax a n d Sax  (1933).  t h e chromosome number f o r 53 s p e c i e s  r e p r e s e n t i n g 16 g e n e r a ,  and then d e t e r m i n e d  the  l e n g t h s o f w h o l e chromosomes, a n d t h e p o s i t i o n o f  spindle-fibre  attachments  o r "centromeres".  They  - 3 -  classified  chromosomes a s " i s o m e r a l "  s i d e o f the centromere), arms), o r " t e r m i n a l " chromosome number", with  the exception  pairs  "heteromeral"  they  report,  Pinus...  and  i n Pseudolarix  arms on  "The b a s i c  " i s 12 f o r most Gymnosperms  o f the Gnetales....  In the Abietineae  i n P i c e a , Tsuga, A b i e s ,  12  Larix,  (and) C e d r u s . . . b u t i n P s e u d o t s u g a t h e r e a r e 13 t h e r e a r e 22 p a i r s o f chromosomes."  made c o u n t s on t h r e e  species o f Abies  A. c o n c o l o r , A. V e l t c h i i ) f i n d i n g  12 t h e h a p l o i d number i n  t h e chromosomes o f A.  and  I , below, i s d e r i v e d from t h e  A. c o n c o l o r .  Table  d i a g r a m s i n t h e p a p e r b y Sax a n d Sax, w i t h i n descending  order of t o t a l  6, P l a t e I I , a r e d i a g r a m m a t i c  They  (A. c e p h a l o n i c a ,  each; and they measured  arranged  either  (with obviously unequal  ( w i t h o n l y one a r m ) .  o f chromosomes a r e f o u n d  and  (with equal  cephalonica  chromosomes  length.  F i g u r e s 5 and  r e p r e s e n t a t i o n s o f t h e same  thing.  I t w i l l be seen f r o m t h e f i g u r e s and t a b l e s t h a t i n both  s p e c i e s , 5 chromosomes a p p e a r t o be d i s t i n c t l y  omeral, w h i l e isomeral.  the other  7 appear t o be a l l  heter-  approximately  - 4 -  Table  I  Chromosome Measurements b y Sax a n d Sax -  reduced  to percent  of total  (1935)  chromosome  length i n c e l l . Abies Chrom. No.  Whole Chrom.  Abies  cephaloniea Short Arm  Long Arm  concolor Long Arm  Short Arm  Whole Chrom.  1  12.00  4.59  7.43  10.16  4.40  5.75  2  10.25  4.59  5.65  9.83  4.40  5.75  3  9.90  4.59  5.30  9.83  3.39  6.44  4  9.55  4.59  4.94  9.49  4.40  5.42  5  9.19  3.88  5.30  9.49  4.06  5.42  6  8.48  3.88  4.59  9.15  4.06  5.08  7  8.48  3.88  4.59  9.15  3.72  5.42  8  6.71  2.12  4.59  9.15  3.72  5.42  9  6.71  1.77  4.94  6.44  1.36  5.08  10  6.71  1.41  5.30  5.76  1.36  4.40  11  6.36  2.12  4.24  5.76  1.68  4.06  12  5.65  1.41  4.24  5.76  1.36  4.40  Sax  a n d Sax a l s o d i s c u s s p o s s i b l e o r i g i n s o f  v a r i a t i o n s f r o m t h e b a s i c h e p l o i d number 12 f o u n d They suggest: result  i n Conifers.  ( 1 ) t h a t P s e u d o t s u g a . w i t h 13, may be t h e  o f the d u p l i c a t i o n  Cupressaceae, w i t h  o f one chromosome;  11, may r e p r e s e n t u n i o n  w i t h one o r more o t h e r s  (complete  (2) t h a t t h e  o f one chromosome  e l i m i n a t i o n o f one  - 5 -  chromosome i s u s u a l l y l e t h a l ) ; 22, may  that Pseudolarix,  probably  They c o n c l u d e d t h a t a l l o f t h e s e changes  been f o l l o w e d by p r o g r e s s i v e  by i n t e r c h a n g e  o f segments and by  Ill  young o v u l a t e  cones  Methods  around  the Gulf o f  Columbia  March, A p r i l ,  and May,  s m a l l amount o f q u i t e v a l u a b l e B.C.  female gametophyte m a t e r i a l  and  t h e same  1948,  by D r .  from and  the  i n the  San  Juan  I s l a n d s , Washington,  very  s c a n t y m a t e r i a l o f A b i e s l a s i o c a r p a came f r o m  Fixation, in  the Appendix.  Belling^  J u l y , 1948.  The  Lake  1921.  embedding and  staining w i l l  be  discussed  H e i d e n h a i n s I r o n Alum H e m a t o x y l i n  Iron-Aceto-Carmine  Drawings  June and  a  A.H.  Hutchinson) from a s i n g l e t r e e a t F r i d a y Harbour during  the  May,  and March, 1949;  Hammond) i n 1940;  (collected  of  Arboretum  staminate m a t e r i a l  ( c o l l e c t e d b y R.E.  Alberta i n  study  Georgia:  i n March, A p r i l ,  most o f the s t a m i n a t e cones f r o m  Victoria,  used i n t h i s  from a s i n g l e t r e e i n the Arboretum  University of B r i t i s h  tree during  have  r e d u c t i o n o f homology  of Abies grandis  came f r o m s e v e r a l l o c a l i t i e s  12  mutation.  M a t e r i a l s and  The m a t e r i a l s  Louise,  with  p o s s i b l y show d u p l i c a t i o n o f 10 o f i t s o r i g i n a l  chromosomes.  1948;  (3) a n d  and  were t h e most u s e f u l s t a i n s .  were made u s i n g  a Reichert  microscope  - 6 -  ( l O x o c c u l a r a n d lOOx o i l - i m m e r s i o n lucida  adjusted  Most o f t h e d r a w i n g s  reproduced i n t h e i r o r i g i n a l  size,  p h o t o g r a p h s were t a k e n on A n s c o roll-film  camera  to g i v e a c o n s t a n t t o t a l m a g n i f i c a t i o n  t h e d r a w i n g o f 1500x.  "120"  o b j e c t i v e ) and a  size,  Rattenbury  using  are here  e x c e p t where n o t e d .  p a n c h r o m a t i c Supreme  t h e same R e l c h e r t  Columbia Arboretum  The  Film,  microscope.  (1945), working w i t h m a t e r i a l from  University of B r i t i s h  on  tree,  the  has g i v e n  an  e x c e l l e n t calendar of events i n the process of microsporogenesis. A t U.B.C.  To  t h a t we  might add  the f o l l o w i n g  Arboretum:  1948  Male D i p l o t e n e and D i a k i n e s i s - Mar.  18  1948  Male  19  1948  Female  1948  Pollenation  At F r i d a y 1948  M e i o s i s complete  - Mar.  Meiosis occurred r a p i d l y  - Apr.  - May  Harbour,  San  Juan I s l a n d ,  Fertilization  A t U.B.C.  data:  23-24  6-14  Washington: - July  4  Arboretum:  1949  Male  D i a k i n e s i s and f i r s t  1949  Male F i r s t  1949  Male T e t r a d s  1949  Pollen  M e t a p h a s e - Mar.  T e l o p h a s e a n d Second Anaphase  fully  formed  - Mar.  10  - Mar.  11  - Mar.  20.  9  - 7 -  IV  Chromosome  Morphology  Prom t h e c o n s i d e r a b l e amount o f c o l l e c t e d f o u r c e l l s were c h o s e n f o r i n t e n s i v e morphology. Cell  These  I - P o l l e n Mother  - Aceto-carmine  Cell,  first  Cell,  - from V i c t o r i a , - Paraffin  Cell  Cell  I I I - Somatic  cell  tree,  first  Mar.  section,  cut into  two  18,  Cell  IV - S o m a t i c  These c e l l s  arranged 4).  alum h e m a t o x y l i n  Washington,  i r o n alum h e m a t o x y l i n entirety  correlation  1948. stain.  metaphase.  J u l y 6,  i n Plates  t h e i r chromosomes a r e shown  seen,  anaphase.  J u l y 6,  f r o m f e m a l e gametophyte,  section,  stain.  sections.  i n descending order of length i n Plate  As c a n be  definite  and  metaphase o f m e i o s i s .  Washington,  iron  a r e shown i n t h e i r  (Figs. 8 - 1 3 )  1949.  1940.  serial  - from F r i d a y Harbour, - Paraffin  9,  from f e m a l e gametophyte,  section,  cell  Mar.  of meiosis.  i r o n alum h e m a t o x y l i n  - from F r i d a y Harbour, - Paraffin  anaphase  smear.  I I - P o l l e n Mother  -  s t u d y o f chromosome  were:  - f r o m U.B.C. A r b o r e t u m  Cell  material,  1948. stain. I I I and  individually, I  (Figs.  individuality  among t h e f o u r c e l l s .  T a b l e ..II, below,  In m i l l i m e t e r s  and  reduced to p e r c e n t a g e s o f the t o t a l  of  lengths  1 -  t h e y show r e c o g n i z a b l e  shows t h e l e n g t h s their  IV  chromatin i n the g i v e n  cell,  and  o f t h e chromosomes as drawn,  and a l s o  the  average  length  - 8 -  p e r c e n t a g e - l e n g t h f o r each.  Table I I  L e n g t h o f Whole Cell  Cell II  I  mm. P e r mm. P e r on cent on cent drawdrawing ing  No.  Chromosomes Cell  Cell III mm. Peron cent drawing  IV  mm. Peron cent drawing  Average Percei  1  35  14.28  31  14.40  28  15*73  32  : 13.05  14.4  2  25  10.20  25  11.61  22  12.37  27  11.01  11.3  3  25  10.20  21  9.77  21  11.80  26  10*60  10.6  4  24  9,81  20  9.32  17  9.56  24  9.80  9.6  5  23  9.40  20  9.32  15  8.44  23  9.39  9.1  6  22  8.99  19  8.85  13  7*31  21  8.58  8.4  7  21  8*58  18  8.38  12.5  7*03  21  8.58  8  18  7.36  15  6.99  12  6.75  19  7.77  7.2  9  16  6.55  14  6.52  11-  6.18  16  6.54  6.4  10  15  6.14  13  6.06  10.5  5.91  15  6.13  6.1  11  14  5.73  12  5.59  10  5.62  12  4.91  5.5  12  7  2.85  7  3.26  6  3.37  9  3.67  Total  245  215  The determined  e x a c t p o s i t i o n o f t h e c e n t r o m e r e c o u l d n o t be i n a l l the c e l l s .  on d e t e r m i n a b l e d i m e n s i o n s ,  m i l l i m e t e r s o f t h e drawn chromosome percentage and  245  178  f o r a l l chromosomes  below, b a s e d  3.3  o f the t o t a l  percentage  average.  shows l e n g t h s i n  arms, l e n g t h s r e d u c e d t o  length o f chromatin  i n the given  N o t i c e t h a t chromosome  c e n t r o m e r e s and c o n s e q u e n t l y ,  Table I I I ,  cell,  1 h a s two  three distinguishable  parts.  - 9 -  Table I I I Chromosome Arm A.  Short  Lengths.  Arms:  Chrom. Cell II No. mm. % 1 3.68 ~9~ 2 3 8 3.36 4 12 4.91 5 10 4.08 6 9 3.68 7 10 4.08 8 2.04 5 9 2.45 6 10 0 0 11 4 1.68 12 0 0 Cell T o t a l 245  .  C e l l. I I mm. % ,  Cell III mm; % 7.5 4.22 5.62 10  Cell mm.  10 9 8 8 6  4.18 3.72 3.72 2.79  8 6  4.49 3.37  4 4 0  2.25 0  0  0  2.25  IV  %  4.08  11 4.50 8 3.36 8.5 3.47 5  2.04  272  0  0 1.4 0  2.5 1.19 215  •  0  178  245  Cell III mm. %  Cell mm.  Average % 3.9 5.3 3.7 4.7 4.0 3.6 3.7 2.4  B. L o n g Arms: Chrom. Cell No. mm. 1 2 3 4 5 6 7 8 9  10  11  12  Cell Total  14~ 17  12  13 13 11 13  10  15  10  7  12 245  Cell II mm.  5.72 6.95 4.91 5.32  5.32  4.56  5.32  4.08 6.13 4.08 2.85  11  12 11 11  10  9  5.12  5.12 4.65  4.18  9 9  6.75 5.06 5.06  10.5 6  4.49 3.93  16  6.54  12  4.91  5.11  TT?  5.31  11  4.50  9  3.68  5.91 3.37  Average % 5.9 6.5 6.7 4.9 5.1  12.5  9.5 4.42  %  6.19  13 8 7  IV  215  178  245  Cell II mm. %  Cell III mm.  C e l l IV mm. Jo  572"  4.7 4.2 6.1 4.2 3.3  Arm:  Chrom. Cell No. mm. Cell Total  i  245  C. T h i r d  1  I  I  4.91  9.5 215  178  5.33  Average j 5.1  245  - 10 -  The  a v e r a g e p e r c e n t a g e measurements o f t h e  chromosomes o f A b i e s  grandis  a r e shown d i a g r a m m a t i c a l l y  P l a t e I I , P i g . 7, a l o n g w i t h f o r Abies  cephalonica  given i n  (1935).  a v a i l a b l e i n f o r m a t i o n about  chromosomes may now  ( P i g s . 5 and 6)  a n d A. c o n c o l o r b a s e d on d a t a  t h e p a p e r b y Sax a n d Sax The  s i m i l a r diagrams  on  be g a t h e r e d  the i n d i v i d u a l  together:  Chromosome 1: - 14.4 p e r c e n t - u n i t s dividing  i t into  3.9, 5.9, 5.1  centromeres  three d i s t i n g u i s h a b l e p a r t s :  units.  - has a p p a r e n t l y ing  i n l e n g t h ; h a s two  three v i s i b l e  a v e r y d e e p one p r o d u c i n g  knob o n t h e 5.1  constrictions a large  includ-  terminal  arm.  Chromosome 2: - 11.3 p e r c e n t - u n i t s  i n l e n g t h ; arms 5.3 a n d  6.5  units; -  the longer well  arm t e r m i n a t e s  i n a small but very  d e f i n e d knob.  Chromosome 3: - 10.6 p e r c e n t - u n i t s  I n l e n g t h ; arms 3.7 a n d  6.7  units; - a slight  c o n s t r i c t i o n midway a l o n g  t h e s h o r t e r arm.  Chromosome 4: - 9.6  p e r c e n t - u n i t s i n l e n g t h ; arms 4.7 a n d 4.9  units;  - 11 -  - a large well-separated  knob t e r m i n a t e s  t h e 4.9  arm. Chromosome 5: -  9.1 p e r c e n t - u n i t s  i n length;  arms 4.0 a n d 5.1  units; - The 4.0 (The  end i s c l u b - s h a p e d w i t h  c e n t r o m e r e shows up w e l l  no  constriction.  i n Cell IV).  Chromosome 6: - 8.4 p e r c e n t - u n i t s  i n length;  arms 3.6  a n d 5.2  i n length;  arms 3.7 a n d 4.7  units; Chromosome 7: - 8.1 p e r c e n t - u n i t s units; - a .distinct  constriction  i n t h e m i d d l e o f e a c h arm.  Chromosome 8: -  7.2 p e r c e n t - u n i t s  i n length;  arms 2.4 and  4.7  units. - apparently of  moves t o t h e a n a p h a s e p o l e s  the other  well  ahead  chromosomes.  Chromosome 9: - 6.4 p e r c e n t - u n i t s  i n length;  arms 2.2 a n d 4.2  units; -  t h i c k l y c l u b - s h a p e d a t t h e 4.2 end.  Chromosome 1 0 : - 6.1 p e r c e n t - u n i t s terminal separated  i n length;  i n position;  centromere  a s m a l l knob  quite  distinctly  b y a c o n s t r i c t i o n a t t h e end  opposite  - 12 -  the  centromere.  Chromosome 1 1 : *  - 5.5 p e r c e n t - u n i t s  i n length;  arms 1.4 a n d 4.2  units; -  t h e s h o r t e r arm i s l i t t l e  b e t t e r than a l a r g e knob.  Chromosome 12: - 3.3 p e r c e n t - u n i t s terminal; The w h i c h was  and  a stout short regular  one v e r y  seemed t o a g r e e w i t h  Some o f t h i s  information  l e n g t h f r o m 14.4 down t o 3.3; t h e y  microns 1500x). cell to  is  on A b i e s vary  vary  The v a r i a t i o n  i n size  grandis in  ends w i t h o u t  t e r m i n a l knobs.  dicentric,  percentage-unit  t o 23  is a  constant to  on d r a w i n g o r f r o m 23 m i c r o n s  One h a s t h r e e  Two  chromosomes h a v e  while  f i v e have  constrictions,  constriction.  four are approximately  d i s t i n c t l y heteromeral  be  i n millimeter-on-  any c o n s t r i c t i o n ,  and f o u r h a v e b u t a s i n g l e  may  o f chromosome 1 f r o m c e l l  19 m i c r o n s on t h e a c t u a l chromosome.  two,  two c e n t r o m e r e s  to 4 microns s i n c e the m a g n i f i c a t i o n  club-shaped  lasiocarpa,  f r o m 35 t o 6 ( w h i c h i s e q u i v a l e n t  i s o n l y f r o m 35 t o 28 mm.  single  chromosome.  than any o f the o t h e r s .  Whole chromosome l e n g t h s  drawing l e n g t h s  quite  A. g r a n d i s i n  l a r g e chromosome" w i t h  one chromosome much s m a l l e r  summed u p .  centromere  s m a l l amount o f m a t e r i a l o f A b i e s  examined,  possessing  i n length;  One  isomeral,  a n d two h a v e t e r m i n a l  one h a s  chromosome  five are  centromeres.  - 13  V  In  Somatic  -  Pairing  the m a t e r i a l of young o v u l a t e cones c o l l e c t e d  t h e U.B.C. A r b o r e t u m i n t h e  s p r i n g o f 1948,  several  somatic  c e l l s were s e e n i n w h i c h t h e chromosomes a p p e a r e d t o paired;  a l l such c e l l s  young o v u l e  or o v u l i f e r o u s b r a c t  gynospore m e i o s i s . a loosely parallel  a not  less  very  easily  j u s t about the  I n many c e l l s ,  the  elaborate coincidence.  e x p l a i n e d away, n o t a b l y  P i g . 14  c e l l was  u n f o r t u n a t e l y s e c t i o n e d by  - 17,  and  But  meiosis.  to those  F i g u r e s 15  and  chromosome 2)  cell  V,  17  are  two  cells  portrayed and  were in  26.  The so  impossible.  But  (chromosomes) i n  fairly  apparent p a i r s of  close pairing.  shows a s t r i k i n g paired  e s p e c i a l l y between t h e p a i r o f i d e n t i c a l close pairing  a t metaphase because t h e s e  15  visual  chromosomes, knobs, and  there i s  the knobs.  the d a u g h t e r  chromosomes a r e  to the p o l e s .  Figure  degree o f  a t the base of  c a n n o t r e p r e s e n t mere s e p a r a t i o n o f  are already going  caused  the microtome k n i f e  of chromatin  s i m i l a r i t y between t h e a p p a r e n t l y  a particularly  merely  seen about d i p l o t e n e i n a normal  chromosomes w h i c h e x h i b i t (probably  of  metaphase  P l a t e V I I I , P i g . 25  t h e r e were s t r a n d s  similar  time  a few  t h a t c o m p l e t e a n a l y s i s o f t h e chromosomes was  pairs  growing  a p p e a r a n c e c o n c e i v a b l y c o u l d be  P l a t e V,  throughout,  be  " p a i r i n g " was  a r r a n g e m e n t o f p r o p h a s e and  chromosomes; s u c h an by  were i n t h e v e r y r a p i d l y  in  This  chromatids  i n anaphase.  They  I f t h e p a i r e d chromosomes  -  14  -  a r e d a u g h t e r chromosomes, t h e a n a p h a s e must be of  homologues;  ipso  in  the  fact  the o v u l a t e  For occurring included  pairing  somatic  i n P l a t e VI,  usual  be  pointed  type  pairing  t i s s u e of Abies  out  F i g . 19 are  of  d e s c r i b e d by  best  The  is  P l a t e V I I I , F i g . 27.  direct  evidence  from the  Here,  It  this of  is  the  pairing  Sax  and  Sax  species are  chromosomes, number 1 i n A b i e s  grandis  The  and  two  three f i g u r e s  diagrammatically i n the  grandis  s p e c i e s , and  study,  cephalonica  (1935).  examining the  c h i e f d i f f e r e n c e s are  b e i n g much s h o r t e r t h a n  on  seen i n the p r e s e n t  chromosomes o f A.  be c ompared b y  t h a n number 1 i n t h e o t h e r  observations  t h e chromosomes o f A b i e s  l a s i o c a r p a ) as  P l a t e I I i n which three  portrayed.  VI)  Discussion  c o n s i d e r a b l y from the  r e p o r t s can  cell  i n c o n c l u s i v e or wanting.  chief point arising  c o n c o l o r as  occur  only.  (and p o s s i b l y o f A.  A.  (designated  and  chromosome m o r p h o l o g y i s t h a t  differ  therefore  i n some f o r m does  t h a t even i n o v u l a r t i s s u e ,  VI  The  must  a more o r l e s s n o r m a l m i t o s i s  of mitosis; c e l l s with  are occasional  We  then  grandis.  scale cell  appearances of p a i r i n g should  i s occurring.  t h a t somatic  comparison,  in a  separation  i f t h e p a i r e d chromosomes a r e h o m o l o g u e s ,  f a c t o , somatic  accept  a  being  length  greatly longer  number 12  i t s counterpart;  and  of  i n A.  i n the  grandis  position  - 15 -  of  t h e c e n t r o m e r e s , number 1 b e i n g  and  12 b e i n g  terminal.  Since  chromosome i s p r i m i t i v e ,  dicentric,  i t i s unlikely  a n d numbers 10 that a  the c o n d i t i o n suggests  a segment f r o m number 12 t o number 1 i n c l u d i n g a  dicentric  a transfer of a portion of  centromere. In t h i s  connection,  Longley  (1941) r e v i e w i n g t h e  c y t o g e n e t i c s o f Zea s t a t e s t h a t i n f r a g m e n t a t i o n  of a  chromosome, a n y f r a g m e n t c o n t a i n i n g a c e n t r o m e r e s u r v i v e s , b u t a fragment l a c k i n g a centromere d i e s u n l e s s itself  to another  irradiation forming tence  chromosome.  On t h e o t h e r h a n d ,  i s known t o h a v e c a u s e d  two f u n c t i o n a l  o f two f r a g m e n t s .  i t can a t t a c h  a split  X-ray  i n a centromere  centromeres and a l l o w i n g the p e r s i s The s e c o n d c e n t r o m e r e i n chromosome  1 o f Abies  g r a n d i s may be s u c h a c e n t r o m e r e f r a g m e n t  to  chromosome.  another  On t h e o t h e r h a n d t h e r e  i s another  possibility.  o u t l i n e o f t h e chromosomes s e e n i n t h e p o l l e n m o t h e r division  i s very i r r e g u l a r with obvious  constrictions.  This, coupled with  seen i n the " r e s t i n g " n u c l e u s  four.  (See R a t t e n b u r y  that  sense) r e - s h u f f l i n g  1945 a n d a l s o t h a t : (a) t h e  on a b a s i c  number  ( b ) The c o n s t r i c t i o n s a r e  p o i n t s o f weakness w h i c h a l l o w f a i r l y ical-time  cell  t h e h i g h number o f n u c l e o l i  h a p l o i d number 12 i s a c t u a l l y a p o l y p l o i d t h r e e o r more l i k e l y  The  knobs and  P l a t e V I , P i g . 18) h a s l e d t o t h e s u g g e s t i o n  of  attached  "frequent"  ( i na  geolog-  o f t h e i n t e r v e n i n g segments so  t h e a c t u a l m o r p h o l o g y o f t h e chromosome i s v a r i a b l e t o a  - 16  degree though i m p o s s i b l e A t any and  by  r a t e the  -  Longley  for  chromosomes r e t a i n  s t r u c t u r e t h r o u g h m i t o s i s as m e i o s i s  examined i n t h e t o be  level  and  events  - events  The all  any  matter of p a i r i n g , I t i s not  them.  d i f f e r e n c e s seem  We  are d e a l i n g  long  one  apparent cases  cell  ago.  Processes  very  s u c h as  evidence  Two  i n true meiosis;  that this  c r o s s i n g - o v e r may  separate  explanation  the  i s that the  form a m o d i f i e d  been  is a partial  other V;  meiosis  to t r u e m e i o s i s ,  present  but  reduction. there i s  segregation.  themselves f o r  physiological.  and  no  and  Cell  take p l a c e , but  other  ovule  been  ( c ) most o f t h e  of genetic  explanations  historical,  not  shortened  achieving true  t o assume a c h i e v m e n t  phenomenon, one  together  t h e r e has  (b) chromosomes a r e n o t  seldom, i f ever,  in a l l  (a) t h e r e h a s  showing v a r y i n g degrees o f a p p r o x i m a t i o n probably  Yet  as  containing a haploid  Three f a c t s :  suggest  continues  g o o d example s u c h  o f p a i r i n g were even more l a x t h a n  three f a c t s  with  species  however, a p p a r e n t l y  common, b u t  sporophyte somatic  t h i c k e n e d a s much a s  first  in a l l cells The  i t i s not a normal m e i o s i s ;  r e d u c t i o n proven;  identity  w h i c h c a u s e d i f f e r e n c e s on a  number o f chromosomes.  these  inside  their  V i s enough t o i n d i c a t e i t s e x i s t e n c e .  probability found  grand!s.  w h i c h must h a v e o c c u r r e d  the time.  Cell  species Abies  between s p e c i e s , n o t  processes  no  Zea.  The  ovuliferous scale  sporangium which once  contained  this  - 17  numerous s p o r e m o t h e r c e l l s . were r e d u c e d  i n the p r o c e s s  progressive  sterilization  t h a n by a s o r t encroaching t i s s u e may  be  Now  i f actual  fertile  o f e v o l u t i o n t o one  tissue  c e l l by  the  o f once r e p r o d u c t i v e t i s s u e ,  of squeezing  sterile  -  tissue,  i n of reproductive t i s s u e the p a i r i n g s  v e s t i g i a l meioses,  seen  evidences  of  i n the  rather by  ovule  incomplete  sterilization.  On (Huskins  t h e o t h e r hand,  1948,  K o d a n i 1948)  instances at least, right  chemical  experiments  by  seem t o p r o v e  Huskins  et a l  that, i n c e r t a i n  m i t o s i s c a n become m e i o s i s when  stimulus i s given.  t h e r e i s some a g e n c y ,  chemical  I t may  be  or p h y s i c a l ,  the  presumed t h a t present  i n or  a b o u t t h e megaspore m o t h e r c e l l w h i c h s t i m u l a t e s i t t o u n d e r go m e i o s i s .  Since the observed  occur i n areas adjacent seems l i k e l y  totic  i n Abies  grandis  to the megaspore mother c e l l , i t  t h a t they represent a spreading  an o u t w a r d d i f f u s i o n quantity  pairings  of t h i s  of i n f l u e n c e or  s t i m u l a t i n g agency i n  t o c a u s e weak i m i t a t i o n s o f m e i o s i s  sufficient  i n normally  mi-  cells.  VII  For  Appendix - C y t o l o g l c a l  this  study over  t h a n 40 were o f a n y experimentation conifers.  value.  to determine  There are  500  Technique  s l i d e s were made b u t  Much o f t h e w a s t e was suitable  technique  fewer  used  up  f o r the  several d i f f i c u l t i e s peculiar  to  that  in  - 18  group o f  -  plants: (1)  L a r g e q u a n t i t i e s o f w a t e r p r o o f r e s i n and  sclerenchyma i n a l l outer  layers preventing  penetration  aqueous f i x a t i v e s ,  hindering (2)  e s p e c i a l l y by  reproductive  tree,  b o d i e s and  making  and  (3)  Low  (4)  C e l l s small  inaccessibility  of  rigidity  time  of  the  i t almost impossible  experiment w i t h  large,  rapid  careful dissection.  Large s i z e of  calendar  hard  the  living  s u r v i v a l rate of so  that  the  to c o n t r o l  or  plant.  egg  cells  in nature.  chromosomes, w h i l e  seldom have a chance t o  spread  out  quite for  examination. (5) Difficulties spot  P r o t o p l a s m damaged by 3,  4,  and  of l a r g e q u a n t i t i e s of m a t e r i a l  chromosomes a c c i d e n t a l l y  For  studying  have whole c e l l s separated  to  sections.  much s u p e r i o r  to  examine r a t h e r For  used,  at p a r a f f i n melting badly.  To  that  there  the  is a  r i g h t stage with  chromosome m o r p h o l o g y ,  this  than  (as  r e a s o n smears  i t i s best in cell (as  w h e r e v e r smears c a n  i t has  plasm's i n t o l e r a n c e o f h e a t  very  i n the  so  on  better the  visible.  sections  embedding must be  heating.  5 make n e c e s s a r y c o l l e c t i o n  chance of f i n d i n g normal c e l l s  ion  moderate  been found  causes long  temperatures  overcome t h e  two  be  that  II)  in cell  I)are  made.  Where  the  periods  of  protoinfiltrat-  to p l a s m o l y s e the  d i f f i c u l t i e s of  to  resin  cells  - 19 -  waterproofing was  and heat p l a s m o l y s i s ,  a special rapid  developed which produced f a i r l y  chief features  technique  satisfactory results.  Its  were: (a) c u t t i n g i n t o s m a l l p i e c e s , (b)  Carnoy's f i x a t i v e , (c) Benzene c l e a r i n g , and (d) speed. The  schedule i s : Carnoy's f i x . : 3 p a r t s 2 parts  Abs.  "Meth. A l e .  Chloroform  1 part Glacial Acetic -  1-2 h r s . (no  Absolute  Alcohol  " 25$  "  -  20 m i n .  -  20 m i n .  B e n z e n e - 75% Abs.  50$  "  - 50$  Alcohol  "  "  -  20 m i n .  -  20 m i n .  P u r e Benzene Chips o f cooled on  Cold  20 m i n . Paraffin Froth  Benzene u n t i l  More c h i p s until  floating  dissolved -  Paraffin Froth  30 m i n .  on Warm B e n z e n e  B e n z e n e more o r l e s s s a t u r a t e d  Warm t o o v e n temp. Pure m e l t e d  longer)  - 20 m i n .  (52°C.) -  5 min.  Paraffin -  20 m i n .  "  "  "  20 m i n .  "  "  "  20 m i n .  Embed. Total  about 5 o r 6 h o u r s .  T h i s was f o u n d q u i t e sporophyte  s u c c e s s f u l f o r a l l young  t i s s u e a n d f o r g a m e t o p h y t e t i s s u e t h a t was embedded  immediately.  S t o r a g e i n 70$ o r 8 0 $ a l c o h o l a f t e r C a r n o y ' s  - 20  fixative  seemed t o h a r d e n  plasmolysed  the c e l l ;  tissues  so t h a t  subsequent  s t o r a g e i n Carnoy's f l u i d  p l e t e breakdown o f a l l c e l l for  -  contents.  The  embedding  caused  b e s t method  found  p r e s e r v a t i o n i s embedding i n p a r a f f i n .  The cells  hardest c e l l s  terrifically  c r e n a t e d and  I I , an a c e t o - c a r m i n e  their  treatment.  aceto-carmine  Cell  I and  cell  Cell  smear; b o t h c e l l s  s w e l l s the c e l l  a  are  i n t h e c e l l ) and  long  the drawing  typical  quite probable  proportionate  lengths of  r a t h e r l a r g e presumption justified  by  itself,  t h e e x p e r i e n c e o f many  Three  s t a i n s were u s e d  chromosomes: H e i d e n h a i n ' s sections;  i t does n o t  t h e chromosome. by  Peulgen's  (23  Very  mm.  little  seems t o h a v e t a k e n p l a c e .  presumed t h a t no m a t t e r  s h r i n k s o r s w e l l s the c e l l ,  greatly.  I I i s 31  i n the c e l l ) .  s h r i n k a g e o f chromosomes, i f any, must be  of  that  l o n g on t h e d r a w i n g  Chromosome 1 i n c e l l  (20 m i c r o n s  of  little.  I i s 35 mm.  microns  is  i s o n l y o n e - t h i r d the diameter  I t i s , of course,  Chromosome 1 i n c e l l  i t still  II,  I , embedded i n p a r a f f i n ,  However, t h e chromosome s i z e does n o t v a r y  on  mother  t h e same s t a g e o f d e v e l o p m e n t , a r e drawn t o  t h e same m a g n i f i c a t i o n .  cell  o f a l l t o embed a r e p o l l e n  because they always p l a s m o l y s e .  approximately  But  com-  how  change  treatment the  This i s actually  but i t i s apparently cytologists.  f o r the study o f  I r o n Alum H e m a t o x y l i n  on  Abies paraffin  Leucobasic Fuchsin with Light-Green i n  a  - 21  alcohol  (Semmens and  B h a d u r i 1941)  Belling's  Iron Aceto-Carmine  and  Green,  Light  differentiation n o t as u s e f u l  -  on p a r a f f i n  smears.  while providing of i n t e r n a l  The  beautiful  structures  as H e m a t o x y l i n  to use  see and  sheath a s o l i d  smears a r e s u p e r i o r  besides providing  t h e chromosomes, chromosomes a n d other  slides  and  careful  i n s t u d y i n g g r o s s chromosome Hematoxylin  blue-black that  f o r c o n t i n u a t i o n o f t h i s work.  because,  Leucobasic-Fuchsin  stains  i s easy  to d e s c r i b e ; L e u c o b a s i c - F u c h s i n i s the s t a i n  Aceto-Carmine  and  i n chromosomes, i s  structure for a preliminary description. b o t h chromonema and  sections,  F o r p o l l e n mother to a l l s e c t i o n i n g  a fairly  to cells,  methods  good s t a i n e d o u t l i n e  t h e y show t h e w h o l e c e l l t h e y do n o t p l a s m o l y s e  of  with a l l i t s  the c e l l  a s do a l l  treatments.  VIII  One  Summary  o f t h e phenomena u n c o v e r e d  studies of Abies grandis Lindley, the e x i s t e n c e o f p a i r i n g t h e v e r y young o v u l e s . pairing  i s not rare  properly recorded.  in cytological  t h e L o w l a n d W h i t e F i r , was  o f chromosomes i n s o m a t i c Huskins  (1948) h a s  shown t h a t  i n the p l a n t world, but i s I t was  thought  cells  somatic  seldom  necessary to undertake  study o f the morphology o f the i n d i v i d u a l  of  chromosomes o f  a the  tree.  C o u n t s and measurements were made on  t h e chromosomes  -  In  several  age of  of  cells,  the  the  total  and  the  lengths of  measurements r e d u c e d t o a  chromosome l e n g t h  located the  and  Chromosome 1,  3,  10.6$  units;  7,  8.1$  units;  5.5$  4, 8,  units;  14.4$  7.2  knobs.  and  have but  dicentric,  four  are  Somatic of  examined.  that  the  units;  10,  units.  Two  as  units;  6.4$  8.4$ 6.1$  c o n s t r i c t i o n , w h i l e f i v e have three c o n s t r i c t i o n s , One  approximately isomeral, two  one  five  showing  The  differences  d i s c u s s e d and  for  pairing.  indication of  so  also  some s o r t  some t h e o r i e s  i n t h i s study are  set  on  conifer forth.  distinct  striking of  between s o m a t i c p a i r i n g  Some p r o b l e m s i n t e c h n i q u e o f methods u s e d  i s so  threads  is  apparent  the  pairing  two,  centromeres.  In  studied,  single  are  e a r l y a n a p h a s e were  cell  club-  chromosome  have t e r m i n a l  f r o m young o v u l e s  units;  has  chromatin strands at one  units;  chromosomes h a v e  single constriction.  cells  11.3$  9,  meiosis are  the  2,  $ units;  s i m i l a r i t y between c h r o m a t i n  somatic  genome a r e  6,  i t i s t h o u g h t t o be  meiosis.  long;  also  The  units;  d i s t i n c t l y h e t e r o m e r a l , and  pairing  percentages.  9.1$  has  a  Positions  5,  3.3$  One  units  cell.  units;  ends w i t h o u t any  four  the  percent-  c e n t r o m e r e s were  r e c o r d e d as  9.6$  12,  terminal  and  In  t w e l v e chromosomes i n t h e  follows:  shaped  -  s p i n d l e - f i b r e attachments or  tentatively  11,  22  reduced  and  the  true  reason  cytology  and  Literature Allen,  Beal,  G.S.,  Cited  1946, "Embryogeny a n d D e v e l o p m e n t Meristem o f Pseudotsuga, I " Jour.Bot.33:666  J.M., 1934, "Chromosome B e h a v i o r i n P i n u s following F e r t i l i z a t i o n " Bot.Gaz.95:660  o f the A p i c a l  bankslana  Chamberlain,  C . J . , 1935, "Gymnosperms, S t r u c t u r e a n d E v o l u t i o n " Chicago, U n i v e r s i t y P r e s s .  Haupt,  1941, " O o g e n e s i s a n d F e r t i l i z a t i o n l a m b e r t i a n a a n d P. m o n o p h y l l a " Bot.Gaz.l02:482  A.W.,  Huskins,  C.L., 1948, " S e g r e g a t i o n a n d R e d u c t i o n Tissue, I" Jour.Hered.39:311  i n Somatic  Hutchinson,  A.H., 1915, " F e r t i l i z a t i o n Bot.Gaz.60:457  Kodani,  1948, "Sodium R i b o s e - N u c l e a t e a n d M i t o s i s " Jour.Hered.59:327  Longley,  M.,  i n Abies  i n Plnus  A.E., 1941, "Chromosome M o r p h o l o g y Relatives" Bot.Rev.7  Rattenbury,  i n Maize and i t s  J.A., 1945, " N u c l e o l a r a n d C h r o m a t i n C y c l e s i n Abies" M.A. T h e s i s , U n i v . B . C .  Semmens, C . J . a n d P.N. B h a d u r i , 1941, " S t a i n i n g Stain.Tech.16:119 Sax, K a r l ,  balsamea"  the Nucleolus"  a n d Sax, H.J., 1933, "Chromosome Number a n d Morphology i n C o n i f e r s " Jour.Arn.Arb.14:356  Table of Plate  I.  Plates  Chromosomes o f A b i e s g r a n d ! s a r r a n g e d i n d e s c e n d ing  order of  length.  P i g . 1 - Prom C e l l anaphase  I - P o l l e n mother c e l l - Aceto-Carmine  P i g . 2 - From C e l l  at  smear.  I I - P o l l e n mother c e l l  m e t a p h a s e - I r o n Alum H e m a t o x y l i n Fig.  3 - From C e l l  I I I - Female  a t anaphase Fig.  4,-  From C e l l  first  at  section.  gametophyte  somatic  - I r o n Alum H e m a t o x y l i n  IV - Female  gametophyte  II.  Diagrams  o f chromosome l e n g t h s  Fig.  5 - Abies cephalonlca  - modified  Fig.  6 - A. c o n c o l o r - m o d i f i e d  Fig.  7 - A.  cell  section.  somatic  a t m e t a p h a s e - I r o n Alum H e m a t o x y l i n Plate  first  cell  section.  i n Abies. f r o m Sax a n d  f r o m Sax and  Sax.  Sax.  g r a n d i s - averages from C e l l s I, I I , I I I ,  and  IV.  Plate I I I . Pig. 8 - Cell Plate  I i n entirety.  IV.  Pig. 9 - Cell  I I - upper  Pig.  10 - C e l l  Fig.  11 - C e l l I I I .  P i g . 12 Fig. P l a t e V.  I I - lower h a l f .  - Diagram  13 - C e l l Cell  half.  o f chromosomes i n C e l l I I I .  IV.  V showing  A somatic c e l l  Somatic  Pairing at early  on t h e t i p o f a r a p i d l y  anaphase. expanding  ovuliferous Iron  s c a l e a t the time of female  Alum H e m a t o x y l i n  P i g . 14  - upper  P i g . 15  - two  P i g . 16  - lower h a l f .  P i g . 17 - two Plate VI.  closely paired  closely paired  chromosomes i n u p p e r  scale  VI - Somatic  ovuliferous mitosis  Pig.  a t " r e s t i n g " s t a g e i n young showing  scale  - Iron  cell  I.  - Cell  I I - upper  P i g . 22  - Cell  I I - lower h a l f .  half.  P i g . 23 - C e l l I I I . 24  Plate VIII. P i g . 25  - Cell  IV.  Microphotographs; - Cell  V - upper  half.  P i g . 26 - C e l l  V - lower h a l f .  Pig.  VI.  27 - C e l l  a t anaphase i n young more o r l e s s  Alum H e m a t o x y l i n  P i g . 21  Pig.  numerous n u c l e o l i ,  section.  showing  Microphotographs.  20 - C e l l  half.  chromosomes i n l o w e r h a l f .  I r o n Alum H e m a t o x y l i n  Plate VII.  two.  cells.  somatic c e l l s  ovuliferous  P i g . 19 - C e l l  cut i n  half.  Normal somatic  P i g . 18 - Two  section - Cell  meiosis.  normal  section.  PLATE  FIG.I  I  1500 X  FIG.2  I500 X  Fl G . 3  1500 X  FIG. 4  I 500  X  n  PLATE  FIG.  5  FIG.  6  FIG. 7  P L A T E EE  PLATE  W  F I G . 13  1500 X  PLATE  FIG.16  1500 X  FIG.17  7500 X  PLATE  in  4*  PLATE  Vil  FIG,23  500 X  •  FIG.20  500 X  ¥ 1 FIG.21  500X  %i w  FIG. 22  500 X  FIG.24  500X  PLATE  FIG.25  FIG.26  500X  FIG.27  500X  500X  

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