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The mission of the International Association of Bryologists (IAB), as a society, is to strengthen bryology by encouraging interactions among all persons interested in byophytes.

Tuesday, October 27, 2009

Re: BRYONET: Ventral surface of a leaf

BRYONET


Dear Bryologists,

The galaxy of eminent bryologists is deliberating largely for the
awaited explanation from the end of Des Callaghan. As he made queries
that why the upper surface of a leaf is termed the ventral side, yet
normally (e.g. a liverwort thallus) the 'ventral' side is the lower surface?

Of course the term ventral sense in the way of Des Callaghan, if
considered differentially for liverworts and mosses.

But in my opinion it applies well for the sense of it is termed and as
long as in practices. The upper and lower surface does not mean to
dissent organisms or part of it for consideration any of the surfaces
(ventral or dorsal).

It is only the substratum (suport) on which organisms or parts of it
withstand, that determines the surface orientation. The substratum (soil
or anything else) supporting growth of thalloid liverworts determines
its orientation of ventral or dorsal side. The surface facing towards
supporting substratum would always be ventral and opposite of it dorsal
one either in liverworts or mosses.

Similarly, in mosses, during growth and development the leaves are
attached to axis, therefore the surface closest to axis will be ventral,
however, the far surface as dorsal one.

As for as adaxial and abaxial terms are concerned, I am of the opinion
of David H. Wagner. As I mean the adaxial term seems to be combination
of two words (ad=adhering; axial=axis) and abaxial (ab=away; axial=axis).

Therefore, in the organisms of erect habit the adaxial and abaxial terms
have clear sense, but in prostrate habit organisms these terms does not
mean and explicate exactly. Therefore, I would be suggesting that these
terms shall be restraint to the plants of erect habit, however term
ventral and dorsal side shall be used to all the plants of prostrate habit.

I hope this little advice from my end would help Des Callaghan to better
understand the ventral and dorsal side in organisms of erect and
prostrate habit.

Sincerely

Dr. Ajit Pratap Singh
Scientist-C
Biodiversity and Conservation Biology Division
National Botanical Research Institute
2-Rana Pratap Marg, Lucknow-U.P.
Pin-226 001-India
Phone No.:+91-522-2297832-33(O)
Cell Phone:+91-9335736749;Fax No.:+91-522-2205836-39
Email:ajitpsingh2000@gmail.com;ajitpsingh2000@yahoo.com

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