In the November, 2008, issue of WGI Online, Ana Veler provided us with the most information ever assembled on the fascinating population of Nymphaea lotus growing in hot springs in Romania. Her hope was that the article would generate interest from others to help answer the questions she asked. Review that article here -
Nymphaea lotus up north, naturally

Update on the Romanian population of Nymphaea lotus: 


N. lotus at Oradea
Photo by Balázs A. Lukács

A Result from
nrITS Sequencing

Research by Gábor Sramkó and Balázs A. Lukács
Reported by Ana Veler, Romania

Gábor Sramkó
University of Debrecen, Hungary 

Balázs A. Lukács
Hortobagyi National Park Directorate, Hungary 

     

In the first installment of this story of a small population of Nymphaea lotus growing in Eastern European hot springs, I asked whether the population is substantially distinct from N. lotus elsewhere. Results are in.

Molecular data (nrITS-sequencing) obtained by Dr. Gábor Sramkó showed no distinction between samples of N. lotus collected by Mr. Lukács from Petea, Romania, and the Nile Delta, and others received from South Africa. This is still work in progress. A summary by Gábor Sramkó of the early results gives a taste of the start:

“The nrITS sequences of two plants from each of the three geographic regions were 676 bp long, and they could be aligned unambiguously. Additionally, no indication of intra-individual sequence paralogy in this biparentally inherited marker was observed, which could have undermined the direct comparison of nrITS sequences. The direct comparison of the aligned matrix showed the sequences were identical, so this DNA region does not separate the accessions from the three locations.

“This information alone would only allow us to draw limited inferences about this similarity. But if we regard the fact that nrITS exhibits one of the highest known substitution rates among plants [II] and we also take the results of Löhne et all [III] into consideration (as extrapolated from their molecular clock calibrated phylogram in Fig. 5., the isolation of Nymphaea petersiana from the N. pubescens – N. lotus sister species can be dated back to approximately 5.1 Mya), we can conclude that the absence of differences in this fast evolving marker serves as hard evidence that the Oradea plant was not isolated from the rest of the populations long ago. Certainly not as long as the onset of the Quaternary era (approximately 2.5 Mya), when the glaciations swept through the subtropical vegetation of the Central European region.

“Moreover, if we compare our sequences to the nrITS sequence of N. pubescens retrieved from GenBank, we find notable dissimilarity in terms of sequence divergence (31 point mutations separate N. pubescens (FJ198406) from our samples). Thus, if so many mutations have accumulated after the isolation of N. pubescens from N. lotus, the lack of difference between N. lotus samples might be indicative of recent intra-specific isolation and/or recent expansion of the species. So, this preliminary result of molecular phylogenetic study suggests the relatively recent introduction of Nymphaea lotus population into the thermal springs of Oradea.

“In order to test the scenario, albeit unlikely, that introduction [I] was recent by migratory animals during the Holocene or human introduction in historical times, more samples of N. lotus would need to be analyzed with high resolution molecular marker systems.”

It must be said that the familiar appearance of the plants and the track record of pre-war academic debate -- alternatively proposing and doubting their identity as a distinct variety of N. lotus, is accommodating the present result all too well.

The small size and isolation of the population may have had slowed its changes over time, at least while such conditions persisted given climate and geologic conditions. “While it may be easy to prove that this has been isolated there for many years,” writes Carlos Magdalena, “it may be impossible to disprove it. What about this plant propagating itself clonally […]? Low variability in a population that is isolated and has no external pressures may lead to not a great deal of change?” [VI]

Such questions are about to be addressed, and the results will add to the interest of the small ecosystem and its floating showpiece. On the side, there is the story of how science was made and minted around these plants, and that’s bound to be worth telling these days. Overall, tropical waterlily pads amid winter snow make their own stories on sight. And where there is curiosity, questions tend to come out …

It may be worth mentioning at this point that one taxonomic revision is not necessarily big news. Although getting names right might appear as an essential foundation of just about any further work, the task of getting ALL names right is anything but [IV] and its assignment provides a fair share of interesting twists to the history of science. Only a few large scale studies find practical need for such a broad perspective [III], and even those may not feel the sting of slight imperfections in the big picture such as this case of taxonomic uncertainty. Unless they do.

If what does happen to an isolated, self-sustaining population of a few thousand N. lotus has any significance, there is still work to be done around Petea lake.

Certainly, the possibility remains that Petea is holding not the last N. lotus to have cheated its way out of the last European Ice Age, but the oldest water garden around those parts. Even as the unintended consequence of some ambitious gardening cca. 1740 [V], the place beckons. What is a good recipe to make a water garden keep itself interesting for two hundred years?

REFERENCES

[I] Geologic dating suggests an age of the geologic formation supporting the lotus population of less then twenty thousand years. Sources cited in the first installment of this story: Water Gardener’s International, Vol.3, No.4, November 2008.

[II] Calonje M, Martín-Bravo S, Dobeš C, Gong W, Jordon-Thaden I, Kiefer C, Kiefer M, Paule J, Schmickl R, Koch MA (2009) Non-coding nuclear DNA markers in phylogenetic reconstruction. Plant Systematics and Evolution 282: 257–280.

[III] Löhne, C., Yoo, M.-J., Borsch, T., Wiersema, J. H., Wilde, V., Bell, C. D., Barthlott, W., Soltis, D. E. & Soltis, P. S. (2008): Biogeography of Nymphaeales: Extant patterns and historical events. Taxon 57 (4): 1123-1146.

[IV] For an example of how and where this argument is made, see:
C. Löhne & W. Berendsohn, “Priorities for the development of a European taxonomic information system”, a presentation delivered to the EPBRS forum [European Platform for Biodiversity Research Strategy], Pruhonice 19-22 May 2009. [http://www.epbrs.org/PDF/Löhne_Berendsohn.pdf]

And one example of how taxonomy gets occasionally patched:
Löhne, C., Wiersema, J. H. & Borsch, T. (2009): The unusual Ondinea, actually just another Australian water-lily of Nymphaea subg. Anecphya (Nymphaeaceae). Willdenowia 39(1): 55-58.
[http://www.ingentaconnect.com/content/bgbm/will/2009/00000039/00000001/art00005]

[V] Some cases of ornamental plants spread into the wild from initial use as garden plants are known – the Roman garden roses and some types of Middle-Eastern crocus are such examples. To date, I am not aware of any such story for an ornamental water plant in Europe. The use of N. lotus as such when the population near Oradea has been documented, first, remains to be clarified. Records of the local administration predate this, but have not been searched for this article.

[VI] Citing an e-mail comment to the article.

     

Nymphaea lotus up north, naturally

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