Wonderous Seeds

Seeds are Wonderous Things - Especially AG white seeds???
CC: to Microscope, BioTeachers, Genetics Lists

When I was age 4 or 5, I was watching Mon wash dry beans for cooking.
She gave me the discolored beans and said, "Plant these and they will
come up." I planted them in the red clay piled up against the outside
cellar steps and in a few days a half dozen bean seedlings were
goosenecking up out of the loose clay. Few events in my life were so
joyous and wonder-filled. Soon I was planting peach seeds, appleseeds,
etc for fun pertending I had an orchard. During the Spring of my second
grade mye parents helped me plant the young trees. By the 8th grade I
had a two acre orchard. 
  During the last two days, 4 seeds of 133 Rivard 1998 (tan seeds) have
been goosenecking out of the soil. One carried its seed coat up and I
removed it today and took it to he lab to look at the empty hull because
I have been saying the white seeds seem to be missing a layer. 
  The brown seed coat has these layers beginning at the outside.
A - hairs on end - 6 units thick - tan color layer. 
B - semi-dense pith - 1/2 unit thick
C - very dense orange brown vessel - 1/2 U thick- like wood of tree
D - slightly greenish pith- huge cells, fragile walls - 2 units thick
E - thin green membrane which is the base of the cells of D 
F - thin smoky brown membrane which protects the embryo, but stays with
the spent shell.
  The total thickness of all these layers was exactly 1 mm. Thus, the
thickness of the erect fibers layer in AG is about 0.7 mm. No wonder the
tan seeds are thicker.
  Next step would be to plant some white seeds and hope for the same
thing. I couldn't wait and got a seed of 482 Welty 1997 (white seeds,
squash) and cut off the distal 1/4 of seed across the seed. 
  There was no external palisade layer of hairs standing on end in the
white 482 seed. No layer A!!
  Next I examined the white seed of a superb 85 lb C. pepo pumpkin
(white) seed sent by Barb Kincaid. All structures and color were the
same except no layer A. 
  I examined 561.5 Welty 1997 (tan seed, pumpkin). This is a spectacular
seed: plump, big, shiny, darkest brown I have seen. It was identical to
all other seeds and has the layer A. 
  CONCLUSION: Tan or brown seeds have an external layer of tightly
packed, perfectly straight, erect fibers which are fused at the tip to
make a hard shiny shell. It will be interesting to trace the origin of
this dominant genetic trait. The standing fibers completely surround the
seed but are 1/4 as long at the edges of the seed. Perhaps Fl would be a
good symbol if it proves to be dominant as shown so far. 
  Tan vs White: A few people have written they hope this tan vs white
study does not reignite the strong debate about whether tan or white
seeds grow the largest fruit. Here is the genetics situation. Assuming
tan is carried on one of the 12 chromosomes of Cucurbitia. Then if the
seeds are tan, the mother had a chromosome carrying the tan allele (the
embryo inside the seed may or may not carry one tan allele). Thus tan is
a marker of little value because it is one generation to early, unless a
thicker seed coat somehow makes bigger pumpkins. 
  
OTHER STRUCTURES of interest.
  There is a huge open air duct running around the edge of the seed and
it has a thin lining. This might help the seed split or move air during
germination. 
  I found no layer at the edge to aid separation of the seed. One might
postulate such a separation layer (leaves have them so leaf can fall off
tree). Or an enzyme might eat away at the edge aid splitting, but no
evidence of such because the pith was intact. 
  When I touched the cotyledons with slight pressure, lots of liquid was
released--perhaps oil. The cotyledons were without structure - no veins
or anything just two lumps of oily nutrition for the young plant. A vein
pattern was found on the surface of the cotyledons, but no veins. I used
15X and 25X. 

ROOTS
  I then examined a plant. It was still in the gooseneck stage and the
cotyledons had raised to 45 degree angle. This plant became visible at
the soil surface 12 hours earlier. 
  I used a camel hair brush to remove the sand. I found 1.5 inch (4 cm)
roots in every direction -- 15 roots. Two spades stuck out into the soil
just above the rooting zone.  As the gooseneck pushes down to lift the
cotyledons out of soil, the two spades keep the pencil pointed radicle
from spearing deep into the soil and tearing the roots off. AG seeds are
wonderous things. 

BIO
  During elementry school I was still interested in seeds and began
selling seeds I had grown to neighbors and made about 50 cents per year
(gross). I collected all sorts of seeds crop and weeds. I wrote that up
for the Westinghouse Science Talent search and got an honorable mention.
Purdue awarded me their 3rd largest scholarship that year. 
  Imagine the superior results you can hope for if you now get up and
give your child or grandchild a wonderous Atlantic Giant seed instead of
some moldy, damaged Navy beans as my moher did.  

THANKS
  The these people contributed seeds or data to this study in the order
mentioned. Barb Kincaid, Rock Rivard, Scott Armstrong, Doug Keel, Nic
Welty, and an unknown kid who threw a pumpkin in our driveway last
Halloween (the seeds had no hairy layer). 
-- 
Harold Eddleman Ph.D. Microbiologist.       i*@disknet.com 
Location: Palmyra IN USA; 36 kilometers west of Louisville, Kentucky
http://www.disknet.com/indiana_biolab/pk709.htm



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