Gee... I should have gone ahead with the message I typed in and then
aborted yesterday, in regard to Kathleen's question. But Gary wrote
before I posted. And I started wrong, as we shall see.
Anyhow... Jon wrote:
>>I had the impression from Esau's plant anatomy text that juice sacs
>>are only 1 or 2 huge cells.
and Gary returned:
>I had the same impression from somewhere, probably not from Esau, which I
>don't have. I even told students they were one giant cell and had them
>measure them for comparison to other cells, but I later read up in Fahn's
>Plant Anatomy (an older text that I happen to still have) and it indicated
>"a number of large juice cells" in the sac or vesicle. I dissected one sac
>under the dissecting scope and it seems to be about a hundred cells, not
>counting the epidermis. If memory serves aright (and my memory of
>measurements is atrocious) they were about 0.5 mm across.
Yesterday, I nearly said to Kathleen that those juice sacs would be
ideal. THEN I decided I'd better check with my favorite days-of-yore
colleague, Katherine Esau. On page 588 of her 1953 edition I find:
"The juice sacs develop as multicellular hairs. The distal part
of each hair becomes enlarged, then the interior cells break down,
and the cavity becomes filled with juice. The basal part of the hair
develops into a stalk supporting the juice sac."
There's room for interpretation there, it seems to me. Although
it develops from a multicellular hair, the juice-filled cavity
is not divided into individual cells. So, Kathleen, you can
present that one any way you like!
(bill)
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