Re: [Aroid-l] Chirality

From: Bob Burns <bobburns61 at yahoo.com> on 2011.11.03 at 06:13:43(22259) Don't know if this is germane to a discussion of chirality in aroids, but palms are distantly related. When I was living in Bangladesh, where the coconut palm is common, I discovered that most (say 19 of 20 or so) were one handed...the easiest way being to look where the flowering stalk came in relation to the leaf stalk immediately below it...to the right or to the left. I was told that below the equator, in the Southern Hemisphere, the percentages reverse, and that this is due to the way the crown of the tree captures sunlight....one "handedness" being slightly more efficient in each hemisphere. It stands to reason then, that, at the equator (provided sufficient generations from seed had gone by to reduce origin influences....which would be quite a while in the case of a coconut palm), that the percentage would be about equal, varying more and more in either direction, the further one got north or south. I wonder if any exhaustive survey has been done on any plant about this issue, even with plants so extensively cultivated, and so obviously chiral, as the palms. Since many tropical aroids also span the equator, maybe something like this is going on with them as well... Bob Burns HTML +More From: Alistair Hay To: aroid-l@www.gizmoworks.com Sent: Wednesday, October 26, 2011 12:00 AM Subject: Re: [Aroid-l] Chirality It is presumably related to the direction of the phyllotactic spiral of the whole shoot. It is perhaps the same phenomenon as the scars on the trunks of Philodendron Sect. Meconostigma, which are shaped either like fat '6's or fat 'd's. > Date: Tue, 25 Oct 2011 12:59:25 -0500 > From: Thomas.Croat@mobot.org > To: aroid-l@www.gizmoworks.com > Subject: Re: [Aroid-l] Chirality > > Dear Ted: > > I was once convinced that the direction of opening was important but a > big survey we did with the way leaves opened proved that this appears to > be perhaps totally at random. > > Tom > > -----Original Message----- > From: aroid-l-bounces@www.gizmoworks.com > [mailto:aroid-l-bounces@www.gizmoworks.com] On Behalf Of Theodore Held > Sent: Monday, October 24, 2011 12:46 PM > To: Discussion of aroids > Subject: [Aroid-l] Chirality > > Dear List, > > Attached here (with luck) is a picture I made of a pair of blooms from > a Cryptocoryne griffithi (identity confirmed by Peter Boyce at the > recent IAS show). What's interesting to me is that the outer spathe > tip (called the flag for Crypts) of the plants twists to the left for > one and to the right for the other. These plants are vegetative kin. > > I have also seen the pairing of left-handed and right-handed > inflorescences on Cryptocoryne pontederifolia. > > Has anyone ever noticed mirror-image flower forms like this with any > other aroids? In chemistry differences involving only mirror images > are referred to as chiral isomers and originate with subtle > molecular-level geometry. In normal life this is called "handedness." > In a plant bloom, the differences may display as macroscopic > phenomena, but likely originate with early development, also perhaps > on a molecular level. > > Please enlighten me if anyone knows about this oddity. > > Ted Held. > _______________________________________________ > Aroid-L mailing list > Aroid-L@www.gizmoworks.com > http://www.gizmoworks.com/mailman/listinfo/aroid-l _______________________________________________ Aroid-L mailing list Aroid-L@www.gizmoworks.com http://www.gizmoworks.com/mailman/listinfo/aroid-l --4756291-119146891-1320300823=:43320-- --==============i88704096854445267==

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