Dave,
Off the cuff, without refs in front of me, if I were a secretory structure,
let's say a peltate glandular trichome (Steffi wanting to use trichomes in an
example????), and the plant leaf that I resided on has evolved to accumulate
particular lipids and other secondary compounds within myself and others that
happen to be toxic or deterrent to herbivores, I would think that I might
have evolved as well, to actively transport water out of me. I want the
concentration of that stuff high, not diluted by water. Now.... My first
question is, did Essau elaborate on the transport? I am starting to doubt my
initial thoughts.... Most secretory structures are basically groups of cells
surrounded by a cuticular layer. The compounds are manufactured in plastids
of the cells, and transported into the space between the cell walls and the
cuticle (sub-cuticular space I believe...). Where is the active transport of
water in all this? GOOD question. One I had not thought of. I will grab my
books, engage my neurons, and try to come up with something.
Steffi
