And here’s the link
.
This EDIT on 16th Jan 2025, is part of an experiment to see if an edit of a 28 day forum post resets the date. (Lavateraguy and me, with help for Ispot HQ are just being inquisitive about the process)
I was rather surprised to see a new family of plants mentioned, but the article does say revealed rather than found. When I tracked it down I understood the subtlety of the word choice - based on earlier studies a new family has been defined for a previously (long) known genus. See this paper in Kew Bulletin. Botanists could just move some genera from Burmanniaceae to Dioscoreaceae, rather than add 4 families to the APG IV complement.
Thanks for the link which has been a fascinating read.
It is a pleasant surprise these days to read that morphological characters are still important and featuring in articles. The comment* about ‘contaminant plastid sequences’ in mycoheterotrophs is interesting.
Afrothismiaceae is not a group I have read about before, (though I know of a UK mycoheterotroph, Monotropa hypopitys, & ispot has observations).
Morphological support for separating Afrothismia from the rest of Thismiaceae has depended on the flowers, root tubers, ovary placenta, fruits, seeds, stamens & a dorsal bract.
Fig. 4, Afrothismia baerae, showing habit, makes it clear why such plants may easily be missed.
*However, the molecular-based analyses used for these classifications included contaminant plastid sequences (Lam et al. 2016), a common issue when using polymerase chain reaction (PCR) amplification to recover plastid DNA sequence data from mycoheterotrophic taxa."
The future: locations lost due to agricultural clearance and the low density where the plants do occur, suggests that extinction is probable for many.
Molecular phylogenies of parasitic plants, especially holoparasites and obligate mycoheterotrophs, has had problems.
There’s a general pattern of relaxed selection and increased rates of drift in parasites, which causes issues in inferring phylogenies (long branch artefacts, etc.). With achlorophyllous plants many plastid genes are until relaxed selection. If the gene has been lost, or has diverged so far that it doesn’t match the primer, there’s a increased chance that the same gene from a contaminant be amplified instead.
A different issue with parasitic plants is that the intimate (at an intracellular level) connection with the host facilitates horizontal transfer of genes, with the result that the parasite appears related to the host rather than to its actual relatives (or hangs around in limbo because of conflicting signals).
Contamination doesn’t only occur with parasites. Extensive horizontal transfer (including genes from mosses) was reported with Amborella. I believe that current consensus is that was contamination instead.
I seem to recall that Amborella was an issue in dim distant past when we were looking at phylogeny of flowering plants
https://onlinelibrary.wiley.com/doi/10.1111/j.1558-5646.1999.tb05367.x
The current consensus is that Amborella is the sister group to all living plants. The cladogram in your citation lines up quite well with modern opinion for more recent splits, but the topology at the base of the tree is quite different. However this might just be a matter of placement of the root - the paper doesn’t seem to explain how the rooted the tree (at least root (in the right context) and outgroup aren’t found by a text search)
That is a sentence that 99% of the population (including me) would have difficulty understanding!
The RSPB has sent an end-of-year cheery message about the great work that they are doing. It includes a note that Turtle Dove numbers have risen by 25% (not sure from what base) in Western Europe. They don’t give figures for the UK as such but they say that rewilding is helping. TDs used to be quite common round my previous home (about 5 miles from where I am now) but I don’t think they have been seen there for a couple of decades. It would be great news if they really did make a come-back.
JoC introduced the term mycoheterotroph into the conversation and I think that is the most difficult word in sentence.
A mycoheterotroph is a plant that is parasitic on fungal mycorrhizae, obtaining energy and organic compounds from its hosts. This contrasts with most plants which are photoautotrophs, obtaining energy from light and fixing carbon from atmospheric or aqueous carbon dioxide. Mycoheterotrophs used to be called saprophytes, as it was thought that they directly exploited decaying organic matter in the soil; but it was subsequently found that fungi were the saprotrophs, and the plants were parasitic on the fungi. Many plants have symbiotic relationships with fungi; this is a preadaptation to mycoheterotrophy.
An obligate mycoheterotroph is one that lacks chlorophyll, and is therefore completely dependent on its fungal host. (This may well be implicit in most uses of the term.)
I wouldn’t be greatly surprised if the word was used in other contexts, such as bacterial pathogens of fungi, but the use for plants at the least dominates.
Other plants parasitise plants. These are divided into holoparasites (such as dodders), which lack chlorophyll and hemiparasites (such as toothworts), which retain chlorophyll, and are only partially dependent on their hosts.
Thanks for the explanation - where do plants that ‘eat’ animals fit into the picture? E.g. Venus Flytrap?
As I presume you know they are referred to as carnivorous plants.
Organisms depend on several inputs. The usual ones involved in defining the various -troph categories are energy and and carbon sources, but organisms also need nitrogen (and very few organisms can fix it directly), phosphorus, sulfur and trace elements. Non-carnivorous plants either obtain fixed nitrogen from the environment, or by symbiosis with nitrogen-fixing bacteria. Carnivorous plants live in nutrient poor environments and supplement their nitrogen (etc.?) intake by breaking down animal tissue. As they obtain their energy from light and fix carbon by photosynthesis they would be considered photoautotrophs like the majority of plants.
My knowledge of biochemistry is rather superficial, and I can’t give an authoritative description of in which form nitrogen enters the metabolic network in each case.
Thanks for the answer! The biological world is endlessly complicated and intriguing.
There’s probably an iSpotter who could tell us
But if not it can be filed under “ A clever bit of biochemistry’.
A little more digging and I find that plants in general take up nitrate from the soil, and convert it to ammonia/ammonium using nitrate reductase and nitrite reductase. (Nitrate reductase was the key search term.) The Wikipedia page on amino acid synthesis has glutamic acid being formed by a reaction between alpha-ketoglutarate and ammonium. Most other amino acid synthesis involves transfer of the amino group from glutamic acid to another amino acid or a precursor.
The use of ammonium salts as fertilisers implies that ammonia/ammonium is alternative external source of fixed nitrogen. The nitrogenases of nitrogen-fixing bacteria reduce nitrogen to ammonia, so I infer that legumes, etc., partially substitute ammonia/ammonium for nitrate.
And I’d speculate that carnivorous plants import nitrogen directly as amino acids, produced from their prey using proteases.
And serendipidously # linking to our other discussion,
A carnivorous sundew plant prefers protein over chitin as a source of nitrogen from its traps.
Andrej Pavlovič, Miroslav Krausko,Lubomír Adamec. 2016.
#Chambers: ORIGIN: Serendip , a former name for Sri Lanka. Horace Walpole coined the word (1754) from the title of the fairy tale ‘The Three Princes of Serendip’, whose heroes ‘were always making discoveries, by accidents and sagacity, of things they were not in quest of’.
Interesting, I have visited Lubomir and have some pictures of his huge colllection of aqutic plants, not sure if I have put any on ispot though. serendipidously
Serendipitous indeed. I’ve not seen one flowering.
Stace says » the shape of the 4-armed bladder hairs ( quadrifids’)& the distribution of the glands on the inside of the corolla-spur are of diagnostic importance. At least 5-10 quadrifids should be examined and therange noted. ».
.
Is Ludomir the ‘expert’ you mention in the post? Did the expert show you these? Or maybe it was so labelled.
.
Here’s his page. Lubomír Adamec
And there’s a picture of his botanic garden pool.
Duplicate hopefully removed,
Yes he was the expert. He did show lots of the plants himself although I also wandered round the collection on my own to some extent and looked at labels. We also went into the ‘wild’ and looked for some of the plants in nature.
Sounds like a grand trip to Cz.
So now I’m wondering why there are different quadrifids; what do they do, & do they all work as effectively as each other;and then about other aspects of these Carnivorous plants.
Utricularia.
This article has videos of Utricularia traps catching prey. I found them compelling to watch, just in case one managed to escape; no spoilers.
https://www.nature.com/articles/s41598-017-01954-3
Most of the literature focuses on animals as prey, so I was surprised to read that it’s not just animal prey, but that lots of phytoplankton are found in bladders examined in this article.
In this study, they investigated the occurrence of algae inside the traps of four species of bladderwort. They observed that algae of 45 genera form up to 80% of the total prey; algae were found frequently in traps without animal prey. The majority are coccal and trichal algae of the families Desmidiaceae and Zygnemataceae.
It’s going to be an interesting Christmas Eve.