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Post by agustinfranco on Jul 27, 2007 22:12:31 GMT
Hi Dave:
I was reading your posts with those of Ron's and i started to imagine a population of tentaculatas trying to hybridize with those of hamatas. I guess we may not see much of that since whatever took place to make these two species, happened already and a newly created species such as hamata would not hybridize with something sharing a large number of the genes it already has! As to the altitude distribution of tentaculatas and hamatas, looks like tentaculatas are more adaptable to a wider range of geographical locations which puts it in similar status as mirabilis: weeds!. Another reason to believe tentaculata gave rise to hamata and not the other way around.
Gus
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Post by phissionkorps on Jul 28, 2007 0:08:33 GMT
Interesting question. I think I would have to assume it is geographic isolation at this point, as I see no genetic reasoning behind this train of though. What I mean by that, is that in the genus (for the most part at least), we do not see postzygotic mechanisms halting "free" hybridization. In other words, pretty much everything can breed with everything else, resulting in viable seed and (usually) offspring capable of reproduction. I think there should be some sort of standard established as to when something ceases to be a hybrid and is called a species. The unforuntate thing is, at least with the current understanding of nep genetics, this is going to be impossible. How many generations are needed? Does a hybrid remain a hybrid all the way until F50 or further, or could it become a species at F8 if the proper environmental factors are there to "push" it? Things only get more confusing when you consider the different ploidy levels that Nepenthes currently exist at, and their ancestral ploidy levels. Maybe "proto hamata" was only 4x? (Here's the paper for all others reading: www.botanik.biologie.uni-muenchen.de/botsyst/karyol.html)You know I have like 48205 different genetic theories about neps (I should write these all down someday lol), but I hypothesized another last night. I think in Nepenthes hybrids, what is controlling their expression towards looking more like the mother or father, etc, is some type of amino acid derivative or steroidal hormone (but I learn strongly towards steroidal). I believe that gene expression in Neps is very much under hormonal control, and one of my current experiments will eventually prove or disprove that to some extent [hormonal control of flower sex]. We're going to have to wait about 4 years to see if I'm right though...
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Clint
Full Member
Posts: 808
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Post by Clint on Jul 28, 2007 1:12:29 GMT
Watch out, the last thing we need is N. hamata with roid rage.
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Post by phissionkorps on Jul 28, 2007 1:40:46 GMT
Hilariously enough, bodybuilders use Conjugated (-)3,4-divanillyl-tetrahydrofuran among other things for muscle/strength gain.
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Post by agustinfranco on Jul 29, 2007 8:03:48 GMT
Hi all:
Regarding the ability of plants to hybridize in nature, no doubt about this being a constant process, but the point I was making is that with tentaculata and hamata, even though there may be a small percentage of hybrid seed between the two from time to time, these will not germinate in the wild since the exchange of genetic material between the two is minimal, for reasons stated above. repeated gene sequences in the progeny is not evolutionarily efficient, unless speciation is again taking place (but not for a hybrid between these two, unless other events such as mutation which may help speciation)
Gus
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Post by phissionkorps on Jul 29, 2007 19:18:08 GMT
Why not? Unless I am somehow misunderstanding that, that is horribly incorrect.
This has absolutely nothing to do with germination rate. The only reason excahnge would be minimal is because they are pretty much the same exact plant. We rarely if ever see postzygotic barriers in Nepenthes.
There's no evidence whatsoever that sequences would be repeated (more than likely they wouldn't). Are you talking about things like satellite sequences? Because those don't do anything anyway, so their presence/absence wouldn't matter. That's like saying offspring wouldn't be viable becuase 1 base pair in one of their introns is going to be different. Regarding changes not being evolutionarily efficient, quite the contrary. Hybridization leads to speciation in Nepenthes. Obviously hybrids are efficient/favored by natural selection (hello hybrid vigor), or they wouldn't occur, or at the very least wouldn't be so prevalent.
Again, in Nepenthes hybridization eventually = speciation. Mutation barely helps speciation, unless we are considering a riduculously long time span, in which case it may help, but probably not. Mutations are for the most part detrimental, or point mutations, which if you remember basic genetics, usually do absolutely nothing.
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Post by agustinfranco on Jul 29, 2007 21:18:31 GMT
Hi Phissionkorps:
If you have not been in the wild, it's pretty clear that only highly competitive seed of any species occupying a habitat or a well established so called hybrid will only germinate. Now you take the same seed put in it TC and you get hybrids not found in nature ie, inermis X bongso or even i dare to say burbidgeae X edwardsiana.
As for the rest of the previous statements Ron, you and I are on the same boat there isn't either evidence for what you state or what i state, so in order to continue discussing, we'll have to look at each point with proof, otherwise we can't continue. agree?
Gus
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Post by Michael Catalani on Jul 29, 2007 22:02:20 GMT
If you have not been in the wild, it's pretty clear that only highly competitive seed of any species occupying a habitat or a well established so called hybrid will only germinate. Now you take the same seed put in it TC and you get hybrids not found in nature ie, inermis X bongso or even i dare to say burbidgeae X edwardsiana.Gus Are you referring just to the Nepenthes genus, or to plant species in general? This certainly isn't the case with a genus such as Sarracenia. In Sarracenia, the odds a hybrid cross occuring in the wild is determined by the following: 1. Proximity of the two species (are they close enough that a pollinator can make the cross) 2. Time of Flower (The flowers of one species must have viable pollen, and the flower of another species must have a receptive stigma.) 3. Flower Height (I have found that taller flowers have a better chance of being pollinated by their own species, whereas shorter flowers have a greater chance of being crossed by the pollen of a taller flower. This could be because flying Sarracenia pollinators have a better chance of encountering a taller flower first, then make their way to the shorter flowers.) A hybrid of S. leucophylla x S. psittacina would therefore be quite rare in the wild. Although they grow in close proximity to each other (ie: amongst each other), their peak flowering times are different by more than a month, which means that S. leucophylla has no viable pollen production when S. psittacina flowers are receptive, and vice- versa. But they do occur, because there's always the chance of an S. leucophylla thats a late bloomer, or an S. psittacina that gets a head start on flowering. If a cross in the wild is made, I have not detected that they have any problems in germination. Their long term viability, however, depends on a suitable growing environment. Sarracenia hybrids often need an environment that is in-between that of the two parents. In the case of the naturally occuring hybrids of S. flava and S. leucophylla, a suitable habitat around their parents is no problem. Both S. flava and S. leucophylla have very similar habitats. Because they also flower at about the same time, this can lead to hybrid swarms where their habitats meet. Now, take the hybrid of S. alata and S. leucophylla. S. alata inhabits areas that are drier than S. leucophylla, although they can grow together in the same bog. S. leucophylla will grow in the lowest and wettest areas (ie: along and in the stream banks), and S. alata will grow in the drier areas up above. Hybrids are quite common, but are more or less restricted to the transitional areas between the two different habitats. There could, therefore, be the case of where S. alata x S. leucophylla hybrids were created, but the hybrids couldn't be viable over the long term (or be very restricted) because of the lack of intermediate habitat at a certain location. Now, I havent seen Nepenthes in the wild, so I couldnt say whether or not they behave the same as Sarracenia. But there could be numerous reasons why two different Nepenthes species dont appear to produce viable hybrids in the wild. The first would be flower timing. The second could be an intermediate habitat suitable for the hybrid if the two parent environments are quite different. I have a very hard time believing that hybrid seed of Nepenthes has any more of a difficult time germinating than the parents, though.
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Post by phissionkorps on Jul 30, 2007 0:00:34 GMT
All nep seed has more or less the same exact chance of germinating. In fact, from all the seed I've sown and grown out, hybrid seed actually has a better chance of survival and grows much faster. The only caveat to this is if a lowland x lowand or lowland x intermediate cross landed on the peak of Mt. Kinabalu. This however, is not going to happen. A hamata x tentaculata cross will have the same exact chances of germinating (and subsequently maturing) at least between 1400 and 2500m (hamata's range). Tentaculata and hamata inhabit the same type of habitat, and tentaculata's range encompasses hamata's. Now, obviously a 700m tentaculata won't hybridize with a 2500m hamata, but hybridization will definitely occur. Since the plants have the same habitat and the same range, and can be found growing less than 100m apart,the hybrids will also favor the same exact conditions that both of the parents do.
Germination rate in the wild is about 2%, regardless of species blah blah blah. If it was so hard for hybrid seed to take hold, why are there so many large stable populations of kuchingensis? Why are these populations taking hold in the same exact conditions of the parents? You said neither of us have proof...but my points clearly do. Look at the natural hybrids....bauensis, kuchingensis, anything that grows around alata x alata, etc.
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Post by Dave Evans on Jul 30, 2007 4:51:34 GMT
Hello Gus , I think either I do not understand what you are saying, or you do not understand something important about Nepenthes breeding patterns... While it is true some possible hybrids are very rare, or they have not been recorded, this does not mean they do not exist and there are therefore impossible because the seeds will not germinate. This is true of some plants, but it is unknown in Nepenthes or Sarracenia. What does seem to be occurring is that some species have stronger barriers which interfere with interbreeding in the first place, like when the species flower. Another barrier can be location. For example: N. burbidgeae and N. edwardsiana do not grow very close to each other, in the future that could change and the hybrid would become more likely. All knowledge we have collected so far indicates all Nepenthes species can make viable hybrid seed with all other Nepenthes. Non-viable hybrid seed is so far unknown in Nepenthes. There is something else I do not understand, it almost sounded like you indicate the hybrid seed "knows" it should not germinate because it knows it will not be helpful??? Did I understand that? I really don't believe the seed can think... Hi Phissionkorps: If you have not been in the wild, it's pretty clear that only highly competitive seed of any species occupying a habitat or a well established so called hybrid will only germinate. Now you take the same seed put in it TC and you get hybrids not found in nature ie, inermis X bongso or even i dare to say burbidgeae X edwardsiana. Gus
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Post by agustinfranco on Jul 30, 2007 10:34:55 GMT
Hi all:
Perhaps it's the lack of availability of data to prove the points stated. technically one can cross almost any two different species and you'll get hybrids, but in the wild the situation is different because there is competition for space, soil, prey, etc. So because one can cross two species in captivity does not necessarily mean immediate reproducibility of such cross and survival in the wild. Seed creation and viability is one thing, fitness to survive in the wild is another.
In other words, Hookeriana may prevail over a ampullaria X thorelli or rafflesiana X thorelli because it's used to grow and thrive in its specific habitat. Again it's not a 100% proven theory because of promiscous imported species taking over pristine environments (exception to this theory). If that's the case the situation changes altogether, but in general i would not expect any manmade hybrid to outgrow and outperform a well-established species or hybrid naturally found.
Gus
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Post by ddionysius on Feb 18, 2008 7:45:55 GMT
my tenta
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Post by Sockhom on Feb 18, 2008 22:49:42 GMT
Hi . Nice plant ddionysos. What a strange tentaculata. It almost looks like a cross with N. hamata . François.
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Post by rsivertsen on Feb 18, 2008 23:06:56 GMT
As I've mentioned in an earlier post, N. hamatus is really just another form of N. tentaculata! -- just as N. emeyie (N. infundibulaformis), is really just another form of N. maxima.
Peristomes and unusual upper pitcher forms alone do NOT justify a seperate specieces in my opinion! Both N. rafflesiana and N. mirabilis have several other ununusal forms that would also qualify as seperate species!
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Clint
Full Member
Posts: 808
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Post by Clint on Feb 19, 2008 1:22:25 GMT
But the peristome is SO extreme. N. rafflesiana and N. mirabilis can't boast a peristome that deviates so much. Even N. mirabilis var. Echinostoma's peristome isn't so defined.
But if it was as defined as N. hamata's, I'd say it deserved to be elevated to species status as well. Especially since two of the native Australian plants have been, as well as N. Sp. viking (well, it will probably be) which are all very similar to N. mirabilis.
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