Date: Fri, 17 Jan 1997 01:48:02 +0900 (JST) From: Fernando Rivadavia <ss69615@ecc-xs09.hongo.ecc.u-tokyo.ac.jp> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg218$foo@default> Subject: Utricularia humboldtii germination observations
To all,
Yesterday I went to Isao Takai's home, near Tokyo. Other than
having had a fantastic dinner prepared by his lovely wife, we also had a
great time discussing CPs. The main reason for my visit yesterday was to
see some of the CPs that Shibata-san brought back from her latest trip to
Venezuela. She was gonna go to Mt.Neblina (where H.tatei var.neblinae
plus the strange D.meristocaulis are endemic), but unfortunately there
was too much rain, and she ended up going to Akopan-tepui (a fantastically
beautiful spot, according to Shibata-san).
Among the live CPs she brought for Isao-san to cultivate were:
D.arenicola var.arenicola, D.roraimae, H.minor, H.sp. (with longer
pitchers and fewer hairs on the throat), B.reducta, B.hectioides, G.sp.,
U.quelchii "pink fl.", U.campbelliana, and U.humboldtii.
Seed pods of U.humboldtii were collected and the day after
Shibata-san returned to Japan she opened the pods and sowed the seeds on
petri dishes together with Isao-san. Of the 3 pods, 1 contained large
green seeds while the other 2 contained smaller whitish seeds (maybe
immature).
After they sowed the seeds, they went for lunch. Now the
interesting part is that 3h later when they looked at the petri dishes
again, they were covered with young seedlings which had apparently
"popped" open from their coats. These seedlings are very curious. They
have 6 arms in the shape of a 3D asterisk. At the tip of each of these 6
arms there is a further subdivision into 3 smaller arms.
Isao-san told me these seedlings were 2mm in diameter on the 9th.
When I saw them yesterday (15th) they were almost 5mm in diameter. Looking
at them today under a microscope, I noticed that from the center of each
seedling is emerging a small bud. These are also 3-tipped a are the
initial 6 arms. Yet these are not connected at the same point. First there
is one division, soon followed by the 2nd division. And together with this
first leaf is the first trap! A few seedlings already have 2 traps.
Isao-san offered a very interesting hypothesis for this quick
germination and the shape of the seedlings. They could be adaptations to
survival inside bromeliads. The quick germination may be necessary, since
rains could probably easily wash out any small particles floating on the
water in the leaf axils of the bromeliads. The many arms present on the
seedlings could thus serve as hooks to grab on to whatever organic
material may be lying inside the leaves of a bromeliad and assist in this
struggle to set a foot in the bromeliad before it is washed out by the
frequent rains in the region where it is native. While observing the
seedlings today, I notice that they truly are very good at "grabbing"
onto other objects.
Now I would like to make a parallel with the closely related
Brazilian U.nelumbifolia, which I found in Feb. of last year, right
before mving to Japan. This species also grows inside bromeliads and is
almost as large as U.humboldtii. Taylor does not mention it in his book,
but seeds of U.nelumbifolia are also drawn by him as transparent
sturctures inside which the embryo can be seen. Unfortunately I can not
follow personally and study closely the U.nelumbifolia introduced into
cultivation last year, but have heard a few reports from my friend Fabio,
who is apparently having great success in cultivating them back home.
His plants have flowered and even produced seeds (I don't know if
he had to hand-pollinate them or not - the scapes we saw in the wild had
no fruit for some reason). He reported that the seeds sown on normal CP
compost did not germinate, while those sown in bromeliads did. Curiously,
U.nelumbifolia seems to be restricted to bromeliads, unlike U.humboldtii
which also occurs in swampy areas. I have no idea how fast the
germination was for the U.nelumbifolia seedlings nor if they look
like those of U.humboldtii. Fabio did send me some seeds, although these
unfortunately did not germinate in the bromeliads at the botanic garden
where my lab is. Maybe like U.humboldtii, the seeds of U.nelumbifolia are
also only viable while they are still green.
Best Wishes,
Fernando Rivadavia
Tokyo, Japan
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