vegetative reproduction (advanced question)

[altum]

Hi there, eh;

I have asked the questions following of some extremely knowledgable people with limited success. If we have a plant biologists or aquatic plant professionals, I would be ecstatic if you would contact me. To save time, I will simply copy my original email & answer leaving out specific names.

I am finishing off a series of lectures which I am presenting to a number of different clubs shortly & would like some clarification on several questions, if you don't mind too much.

1/ scientific literature is vague & contradictory on the specific differences amongst bulbs, corms &
tubers. Many authors seem to lump everything under bulbs but the Aponogetons, by definition,
can not fit into this category. To me, they present like tubers being able to produce multiple plants
from many different eyes. Any help here would be appreciated.

2/ asexual reproduction in Echinodorus can be accomplished in several ways. However, every author
that I've read so far calls the long, plantlet-bearing 'stems? inflorescences?', stolons. Stolons, again by definition,
only produce plantlets at the apex. Echinodorus produce multiple plantlets on these stems? inflorescences? . Could
you please clarify this for me?

I know that most audiences don't know or care about these differences, but I don't want to
disseminate incorrect information anyway. Of course, I also want to know just for me!

Thank you for considering a response.

TTFN, eh

Jim Robinson

And a response.

According to Christel Kasselmann (Aquarium Plants, p. 74), species of Aponogeton are the only aquatic plants producing tubers. However, she says that they are incapable of producing brood tubers. This suggests to me that one plant produces one tuber that produces one plant. Here's where you may need to write her for further clarification.

As to Echinodorus, "the formation of adventitious plants on the inflorescences, leaves, petioles, and roots of the parent plant are well-known" (Kasselmann, p. 73). Indeed, my Echinodorus (E. major, E. bleheri) routinely form multiple baby plants on the inflorescence stem. This stem with many baby plants lies along the water surface. The same E. bleheri also produces a thicked rhizome. If I cult this rhizome into 2 cm segments with a razor blade, the segments will also produce adventitious plants.

Hope this helps. If you have further questions, I would suggest writing to Ms. Kasselmann or the more knowledgeable folks at Tropica.

If anyone does have Christel Kasselmann's email address, would you please be so kind as to send it directly to my email ( [email protected] ) rather than through this forum.
Again folks, I would appreciate any help you can give me!!!
TTFN, eh
Jim Robinson

 

[Tom Barr]

Kasslemann is glaringly mistaken suggesting that only Aponogeton produces "tubers", the world's worst and most studied submersed aquatic weed, Hydrilla vertilicillata forms dormant "tubers".

She's welcomed to explain what these are:
http://plants.ifas.ufl.edu/wthhydtub4.jpg

And they are the worst thing in the world to remove!
1000's per m^2!

So do many pondweeds in the Potamogeton.

My old job and dept:
Hydrilla

More precisely, what is a tuber?
Do not use the term "bulbs", use tubers or rhizomes.
Corms are

Turions ("buds" in some of the leaf axils). we see these in Utricularia vulgaris here in CA, a pretty alpine plant.

Subterranean turions ("tubers"), are yellowish, potato-like, attached to the root tips in the hydrosoil.

Hydrilla tubers may have multiple meristems.

And that's just here in CA/USA.
These do not originate from the rhizome or root, rather, are borne from the adventerous shoot that points downward typically(unlike a turion) starting late Aug in the N hemisphere till around the end of Oct/Nov(now).

Think Potatos vs Yams, one's a swollen stem technically and the other is "root" tuber.

Both are tasty though.

There may be other plants
Taro is a corm. Another very commonly studied plant anyone can look up on line under Google scholar and find a large amount of research on.
Corm - Wikipedia, the free encyclopedia


Kasslemann came here and showed a mountain of evidence about the oligotrophic nutrient free essentially water column parameters that Echinodorus live in and how she travels to these natural habitats to study them.

I asked her if she measured pore or sediments: No".
Aquatic plants are opportunistic, they will take from wherever they can get the nutrients, a simple water column test shows these genus grows rapidly, as do Aponogeton and most all species, without any nutrients in the sediments.
Natural systems typically show the same pattern with sediments.

You need to measure both locations for nutrient sources.
Not just one if you plan on doing any research or ecology on aquatic plants.
Otherwise you miss important data that's very relevant to the plant's ecology.
I like her passion, really good work in some areas.

Some good reference materials for the questions:

IFAS aquatic weed site.
Google scholar
Sculthorpe's Biology of aquatic plants, a good book for hobbyists a very well written.
Hutchison's Treatise on Limnology, Book 3, Aquatic Botany.

FYI, Lace plants are well studied as well.
And they have multiple meristems coming from the tuber.
I am not an expert on Aponogeton however, I believe one in the genus has a rhizome, not a "bulb"(A rigidifolius?).

http://www.rbgsyd.nsw.gov.au/__data/assets/pdf_file/73129/Tel8Hel007.pdf

If a plantlet is formed from the "peduncle", is now a stolon as well I would argue.
http://links.jstor.org/sici?sici=00....0.CO;2-I&size=LARGE&origin=JSTOR-enlargePage

also:
Echinodorus peduncle - Google Scholar

So use "peduncle" as the term to talk about the structure that bears the "daughter plantlets". Why make seeds when things are good in a spot and stable? Seeds are produced when times are tough and ........drying out. Not like our aquairums. Easier to make daughter colons and take over a good area.
Aquatic plants are popular because they can be reproduced easily via colons/asexually.

I've yet to see any daughter plants formed from the leaves, or petioles of Echinordous. the pedunlce, yes, the Rhizome, yes, but not these other structures.
This might be due to poor translation, rather than her.
Cut a leaf off ands see if you can grow a planlet, or a leaf stem(petiole) from any species in the genus.

Good luck.

Here's some more:

Bulb - Wikipedia, the free encyclopedia

Hope this helps and I did not make too many mistakes

Tom Barr

 

[altum]

Thanks Tom, eh;
Kasslemann is glaringly mistaken suggesting that only Aponogeton produces "tubers", the world's worst and most studied submersed aquatic weed, Hydrilla vertilicillata forms dormant "tubers".
You are absolutely right on this point!

And they are the worst thing in the world to remove!
1000's per m^2!


At one time these were illegal to import or even own, in Canada. They have now eliminated all aquatic plants from the restricted list, even Myriophyllum

You need to measure both locations for nutrient sources.
Not just one if you plan on doing any research or ecology on aquatic plants.
Otherwise you miss important data that's very relevant to the plant's ecology.

Again, absolutely right! In any experiment of any value at all, one MUST control ALL of the variables & test multiple times. These results must also be reproducable by independant research

Turions ("buds" in some of the leaf axils). we see these in Utricularia vulgaris here in CA, a pretty alpine plant.

also in the genera Potamogeton, Aldrovanda and Utricularia.
Are they not produced in response to unfavourable conditions such as decreasing day-length or reducing temperature?


I am not an expert on Aponogeton however, I believe one in the genus has a rhizome, not a "bulb"(A rigidifolius?).

Again, absolutely correct. A. rigidifolius also will reproduce using gemmiparus reproduction.

If a plantlet is formed from the "peduncle", is now a stolon as well I would argue.

Hmmm. The definition of stolon though is ' horizontal stems which grow at the soil surface or below ground forming new plants at the ends or at the nodes & is similar to a rhizome, but instead of being the main stem of the plant, which is what a rhizome is, a stolon sprouts from an existing STEM and has long internodes and generates new shoots at the end.

So use "peduncle" as the term to talk about the structure that bears the "daughter plantlets".
That's great info. There were absolutely NO references to be found for this info.
I've yet to see any daughter plants formed from the leaves, or petioles of Echinordous. the pedunlce, yes, the Rhizome, yes, but not these other structures.
Are you referring to the carrot-like appendage at the base of the crown, a rhizome? I always thought that this was a tuber too. To me, they present like tubers being able to produce multiple plants
from many different eyes & also by gemmiparus means.
Once again Tom, THANK YOU!!
ttfn, EH
Jim Robinson