Ping theories

Barry Meyers-Rice (barry@as.arizona.edu)
Thu, 17 Mar 94 08:40:30 MST

Jan, before I left for California, I told you I had been developing a few
hypotheses about Pings. I had been struck by your interpretation of Ping
morphology, that the plant is a rosette of leaves, terminating in a long
*pedicel* (not peduncle) emerging from the rosette, at which point axillary
buds produce new growth and that is how the plant continues after flowering.

That is your stance, correct?

I had been thinking how this theory made sense, because occasionally
one of my Pings will develop two crowns in the rosette which may take a
few years to separate fully. This usually happens after flowering, presumably
when two axillary buds have been activated.

I had also been thinking about how boreal Pings produce hibernacula
(winter resting buds) and how at this time of the year they often
produce gemmae buds as well. I was thinking that I don't recall ever
having seen a plant produce these gemmae buds if the plant was grown from
seed and had not yet flowered for the first time. In other words, flowering
seems to be a prerequisite for gemmae production. Since gemmae buds
probably form from axillary buds, would it make sense that when a Ping
germinates, there is so much apical dominance from the auxin at the
apical meristem that there is no or little chance of gemmae production,
but then after flowering, apical dominance is lost, an axillary bud
starts up new rosette growth, and at the same time gemmae bud growth
is initiated.

This is a far more interesting idea to me than what is probably really
going on i.e. flowering and gemmae production are both symptoms of a
mature plant, and there is no further relationship between these two
activities.

I haven't had much experience with gemmae-forming Pings. Any Europeans
out there have data that can quench the flames of my flickering theories?

Barry

P.S. The tattered remains of my _P.leptoceras_ corolla fell off. I take
it as a good sign that, while I see no evidence of swelling capsule, at
least the pedicel has not withered.