Aldrovanda Cultivation

[Apoplast]

Hi Richard - I can't answer where you can get plants in Oz, sorry. But given the fantastic environment you live in (I'm simply green with envy!), and other utric you may consider is U. reflexa from Africa. I'd heard that it can develop quite large traps under the right conditions, and thank to Bob's CP photo finder I've found a shot that suggests what I had been told was true. I'm not sure if where you live might get too cool or not, but at the very least I thought you might be interested. Good luck!

[adamcross]

Richard, I'd suggest your best bet is probably trying to source some U. vulgaris seed from one of the European societies- it germinates fairly readily in my experience and will grow from seedling to choking a cultivation tank in a matter of a few short months. Apoplast has a good point with U. reflexa; if you have the opportunity to get your hands on this species or any of the other tropical aquatics then snatch the chance!

Keep me posted as to how your Aldrovanda growing goes, I'd be interested to hear how you fair! Drop me a line if there's anything I can help you with in regards to the cultivation.

[adamcross]

Another update on the Aldrovanda: despite nearing the end of the growing season, and heading into winter, most of the tanks still have plants flowering and setting seed. Exemplifies the bumper season we've had- over 2,000 flowers and nearly 4,000 seeds. Things are starting to look a little scrappy as the weather cools and the day length shortens, but the plants don't look like producing turions for at least another month or so yet.

[meadowview]

Hi Folks:

And we're all looking forward to Adam discussing Aldrovanda cultivation at our symposium, Crossfest 2013!, on June 29 at the Town Hall in Bowling Green, VA. See our website for details at www.pitcherplant.org and don't forget to register.

Sincerely,

Phil Sheridan
Meadowview

[adamcross]

Another quick update: these are the seeds I've so far harvested from my plants this year (first half of the fruiting season; around 2,400). I'd be expecting about the same amount still to come. As far as I'm aware (from the published literature), that Petri dish contains the largest single collection of Aldrovanda seeds to date, worldwide- though if I'm wrong and there's anyone out there who has harvested similar amounts, I'd love to hear from you!

These will all go towards completing an ongoing study of seed ecology and germination biology in A. vesiculosa.

[Apoplast]

Hi Adam - Congrats on a fantastic seed harvest! Thanks for sharing a shot of it too. Were these seeds the sum total from all of your location types? If so, are they all open pollinated? I'm wondering if out-crossing might increase seed set or viability given the fairly low genetic diversity in the species. Or is there so little difference between locations that it's unlikely to matter? Good luck with your research! I look forward to reading the published results, and very much appreciate you sharing with us here!

[adamcross]

Hi Apoplast,

All of these seeds originate from the SE Australian population, which is now extirpated (a road was built through the middle of the swamp). Other populations are kept separate and produce only limited seed, however pollination is not an issue: the flowers fit no pollination syndrome (insects/wind/water etc), are obligately autogamous, and only the curved style morph leads to fruiting success. I've spent time around my plants for hours virtually every day over the last few years, particularly over the flowering period, and I have never observed any visitation by a pollinating organism. Pollinator exclusion trials have confirmed that even if any exist, they are unlikely to play a significant role.

In regard to outcrossing: seed/maternal genetics support obligate autogamy, and the genetic variation both within and between populations is so limited that outcrossing essentially achieves the same result as self-pollination.

[Apoplast]

Hi Adam - Thanks for the response! I'm learning a ton about this species by corresponding with you here. It's much appreciated! It sounded from your response like the SE Ozzie population (which is sadly extirpated) has a fairly good seed set compared with other locations. Does that mean that the SE Oz population has more of the the curved style morph?

I know you said that hand pollination has shown limited success, but other obligately autogamous species can be hand crossed. For Aldrovanda, is the seed set just so low it is not worth it, or does it really invariably fail? Regardless, this all seems to add up to one species (and genus) that is in a lot of trouble.

[adamcross]

The seed set appears most dictated by environmental conditions and prey factors- all of the seeds harvested from my plants this year come from two cultivation tanks, while plants growing side-by-side in otherwise identical cultivation tanks abort to produce no seed. In previous years, the tanks that are now producing buckets of seed have produced none, and vice versa for the tanks producing none this year. From what I can tell in the literature, the curved style morph exists in equal proportions across the globe, with the ratio of successful:aborted fruit around the 60:40 level throughout Europe and Australia.

Seed set is equally comparable, and equally influenced by external factors- natural seed set in Europe varies from a mean of 2 to a mean of 8 seeds per fruit, and in my cultivation the mean usually swings between around 5-8. Seed viability is then another confounding issue, as generally speaking only 30-50% of seeds produced are actually filled.

So, essentially, the plant has numerous mechanisms in place to limit sexual reproduction where possible. Yes, it is true that cross-pollination may increase the success of fruit development, and the number of successfully fertilised ovules (several studies have examined this). However, habitat factors influence seed development, and even in optimal conditions the development of seeds does not guarantee that many of those seeds will contain a viable embryo. Then comes seed dormancy and all the subsequent mechanisms regulating the germination of those seeds.

The lack of seed production (and therefore sexual reproduction) isn't doom and gloom in itself though. Aldrovanda has evolved to perpetuate a stable and persistent genotype capable of exploiting a specific ecological niche, and achieves this through a high vagility of asexual propagules. If the worldwide decline of wetland habitats were to cease today, and the habitat and biotic linkages of remaining sites were to be restored to pre-European quality, Aldrovanda would likely flourish. Sadly, that scenario is entirely wishful thinking- even conservative estimates suggest that on current trajectory we are likely to witness its extinction in the wild within the next 50 years.

[meadowview]

Hi Apoplast:

Why don't you come to Crossfest 2013 and examine all these interesting Aldrovanda issues with us? Our Aldrovanda is pollinated by small bees and sets seed so we are very excited to look at this when Adam visits in late June.

Sincerely,

Phil Sheridan, Ph.D.
Director
Meadowview Biological
Research Station

[Apoplast]

Hi Adam - Thanks for so patiently and thoroughly responding to my constant barrage of questions! You detailed responses have increased my appreciation of this species. I think after your last post I have a better idea of what's happening with this species vis-à-vis reproductive biology. It's interesting that Phil noted visitation by small bees in North America. I wonder, given the rather large geographic extent of the native range of this species, if there might be differences in pollinator efficacy. It just gets more interesting all the time.

Hi Phil - Thanks for the suggestion. I certainly would attend if I could. I have no doubt that a discussion between you and Adam would be worth the airfare alone, and I'm sure there will be others there who would make the discussion even more engaging. I hope it all goes well, and I hope you post a summary and photos on the "Meeting Announcements and Reports" board here. It promises to be fun and I am sad I will miss it, but at least with a good report here I can have a virtual review of the meeting.

[adamcross]

On that topic, for anyone interested and attending, I will be bringing seeds of the Esperance population with me which will be available at the Meadowview event.

[pearldiver]

Hi,

Do you perchance know of a US based source for red Aldrovanda, Australian or Hungarian? I am drawing blanks except for overseas orders with lots of extra difficulty. I am growing green (not sure of the original locality) in a couple of water features with lots of companion plants and they do quite well. Just want to branch out some and it seems to be like unobtainium. Thoughts, ideas? Thanks.

Paul

[adelea]

Hi Adam, I'd love to organise a trade, but as trade/purchases are not permitted on this forum please email me at
[e-mail]
or
[e-mail]
I am in Au so freight is not a real problem.