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Myrmecodia lamii - pollination


Andreas Wistuba

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I always wondered why a ceistogamous flower should have means to prevent self-pollination. In Myrmecodia lamii the stigma in some flowers is arranged above the anthers and thus does not allow for self pollination. In others it's the other way round (=heterostyly).

BUT, the flowers never open!

 

This does not seem to make sense at all...?!

 

I think it has not been observed before. I saw one way how natural pollination works:

 

Ants remove the upper part of the flower and are absolutely crazy for the nectar inside. The plant nicely protects the nectar from any hungry anymals except for "her own" ant helpers! 

 

I think this explains, why many of the so called cleistogamous Myrmecodias never set seed in cultivation: They simply are not cleistogamous at all but simply lack their natural pollinator.

 

 

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Andreas:

 

Thank you for clarifying that Myrmecodia lamii is heterostylous since this is not evident in Huxley & Jebb probably due to the very small number of flowers available for examination by the authors (two).

 

Over the past month I have dissected >50 flowers of several heterostylous Myrmecodia taxa (tuberosa 'lanceolata', erinacea, sp. cf. alata and the sp. that we have here as both "Manokwari, Irian Jaya" and my "Goose" which are, IMO, the same taxon) as well as a number of cleistogamous taxa such as platytyrea var. antoinii, tuberosa 'papuana', etc. For those unfamiliar with the internals of these flowers, the most reliably self-pollinating forms have the stigma lobes located in the upper parts of the corolla at the same level as the anthers and in contact with them at anthesis, while the heterostylous taxa generally have the stigmas located well above or below the anthers (occasionally at the same level in some taxa). My previous multiple attempts in 2014 at manually pollinating one of the heterostylous plants mentioned above ("Goose") all failed. I now believe that this lack of success may have to do with deficient pollination technique and I am now revisiting this experiment on all of the taxa mentioned above on a systematic basis two or three times weekly in order to try and generate seed from these plants. The question remains whether these plants are self infertile, or whether two plants possessing flowers of the same -styly can be successfully crossed. I expect to resolve these questions by mid-2016.

 

From my recent experience readers attempting to pollinate the heterostylous taxa should be aware that they have a very, very narrow window of opportunity to harvest dry, viable pollen and match with receptive stigmas (generally evincing lobes extended like a starfish, not closed at tips). Obviously, having large, profusely-flowering plants at hand is a plus. Brevistyle flowers generally will leave the stigma attached to the plant when pulled for pollen harvest, while longistyle flowers will generally emerge intact if pulled carefully.

 

I have attached an image of a M. sp. cf. alata showing a receptive stigma (located halfway up image in center, alongside closed flower) following the removal of the upper two-thirds of the corolla to facilitate manual pollination. A partially dissected flower is visible on the stem to the lower left.

 

Cheers,

 

J

 

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Camilla Huxley-Lambrick's doctoral thesis may be found here, but note that it is copyright. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.347001

    If too busy to read the entire article,  I suggest searching for the word "heterostyly" which will take one to subjects pertinent to this thread.  Note that the pollen in heterostyle flowers is morphologically variable. 

Something I have read in the literature gave me an impression that hydnophytinae heterostylus flowers had measures to control self fertilisation OTHER than the flowers obvious stigma/anther differences, but I have been unable to locate the notes.  M. erinacea another subject that is pertinent also has a few mentions.  Of course, much has changed since this study was done.

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Derrick:

It is worth noting that - unlike the cleistogamous taxa - it appears that stigmas are not obviously receptive in synch with pollen production in the heterostylous forms I'm currently working with. Thus, one cannot self a single flower and expect successful pollination and subsequent fruit production. I also suspect that there may be less obvious genetic barriers to self pollination in play as well, but the mechanical and phenological obstacles to self pollination in these taxa are quite formidable in their own right.

I wonder whether any of the longer term growers in the EU or Asia have successfuly hand pollinated any of the heterostylous hydnophytines? I believe that they have not been in cultivation long enough in the US for anyone other than Frank to have tried.

J

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Hello Andreas,

 

Many thanks for sharing your in situ observation, which could really us us in the understanding of these enigmous species. Especially with M. lamii, which is particularly annoying for growers who try to obtain seeds ;) !

 

If these myrmecodomic plants are also myrmecochoric, the interactions between plant and insects are closer than previously supposed.

 

All the best,

 

Aurélien

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Andreas:

 

Last year I wrote that Myrmecodia beccarii appeared to set fruit about 60 days after pollination. That was apparently incorrect. From more careful observations made over the past year, I would say the time range in members of the genus that I grow here ranges from ~100 days to ~180 days, so is much more in line with Frank's estimates of "three to six months". As you know, fruit is generally visible in the alveoli very shortly before it ripens, unlike the case in Hydnophytum, where nearly full sized green fruit can take ages to ripen in some species.

 

J

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Coincidentally, there was a nearly fully-emerged Myrmecodia lamii flower available for partial dissection when I went to the greenhouse yesterday afternoon. Note that this is on a seedling plant in a 15 cm basket, but  corolla dimensions and general description as per Huxley & Jebb. What I found very interesting is that the closed flower showed no evidence of having dark anthers. When blue or bluish anthers are the case, these are normally visible through the corolla walls in other taxa. Flower substance thick and rather brittle, corolla lobes fused.

 

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Upon removal of the apical portion of the corolla, I was quite surprised to see how dark the anthers are. Stigma is sited well above the anthers, presumably a longistyle flower if this species is indeed heterostylous. Corolla four-lobed, not receptive in this image. Would expect lobes to extend over next 48 hrs.

 

 

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Cheers,

 

J

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Fantastic Jay!  That is what, a two year old plant?   Fantastic job growing that, just great!  I had no idea flowers could happen so early on this species.  You have a marvelous growing system set up for yourself.   Thanks for sharing all of this with us.

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Hi, Andreas.

 

The "dirty" grow mix I am using now has nutricote six month formula 13-13-13 + micros in addition to encapsulated gypsum and a small amount of processed dolomite blended in to compensate for the mineral free water in this area. I do not supplemental feed plants in this coco fiber mix on a regular basis, but when I do it is with Maxsea 16-16-16 at 5 cc x 3.80 lt, i.e. at concentration suitable for epiphytic orchids.

 

Because of the ongoing California drought, I am concerned that the superb water quality that we still have in this area will deteriorate markedly in 2016. I have been gradually moving many of my plants out of pure New Zealand sphagnum in preparation of this event and into a substrate that will hold up well for many years with water of much worse quality than we have now.

 

As we have discussed in the past, I feed my hydnophytines at higher frequencies and at higher doses than most growers can because I water copiously every couple of days with municipal water with ~30-40 ppm TDS and have near optimal growing conditions for both lowlanders and cloud forest forms. The resultant leaching necessitates higher rates of fertilization than most hobbyists would be successful with, but does boost growth rates way past those witnessed in Guatemala. I drench feed hydnophytine seedlings in sphagnum weekly as soon as the cotyledons are free of the seed case, at the rate mentioned above for orchids. Seedlings are watered at two-three day intervals with RO/distilled and fertilized on third pass, so more or less every seven or eight days.

 

Thanks again for your incredible generosity over the past years. It would be marvelous if we could start producing Myrmecodia lamii in the EU and the US on a regular basis.

 

Kind regards,

 

J

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Another interesting snippet from the Huxley-Lambrick thesis. "The pollen is of considerable interest because it shows great variation between and within genera and species."  This of course raises some interesting questions especially in regard to current taxa delimitations. Bring on the phylogenetic studies!

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Bonjour

 

 
very interesting discussions

 

Can you tell us more about the story of anthers of color? on M.lamii ?

M.brassi has blue anther

 

may be an interesting docu on the heterostyly :

 

Morphs differ in the length of the stamens and styles. In addition, they often differ in size and the number of grains of pollen products and sometimes by the structure of the exine, the color of pollen, the presence or absence of starch in the pollen, the structure of stigmatic papillae and size of the corolla The two plants have distyliques morphs and tristyliques plants have three. These are more rare; we only find them in some Lythraceae (eg. Lythrum salicaria), Oxalidaceae (Oxalis pes-caprae) and Pontederiaceae (eg. Eichhornia paniculata) and two other families where their presence has not been confirmed: the Connaraceae and Linaceae Among distyliques plants are found many species of Primula, the Flax grown and other species of the genus Linum and many species Cryptantha.

In distyliques species, flowers (and thus, by abuse of language, plants) are either brévistyle kind ("thrum" in English) with shorter styles stamens (see figure) or longistyle kind (" pine "in English) with longer styles stamens.

In tristyliques species, the flowers of each morph are characterized by three levels, two of which are occupied by the anthers and the third by a stigma. Styled flowers therefore have a long style and medium and short stamens. Mésostyles The flowers have a medium length style and long and short stamens short-styled flowers have a short style and medium length and long stamens.

In most cases, the different morphs of heterostylous species are mutually compatible (called legitimate crossings), while the pollination of plants of the same morph pollination and self-incompatible (called illegitimate crossings) For example, in the case of distyliques species, the pollen produced by the long stamens is compatible with long styles and pollen produced by the short stamens is compatible with the short styles. The population is divided into two consistent groups.

 

 

have you a docu on the myrmecodia /hydnophytum  cleistogamy ?

 

jeff

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From reading this article below, It appears that there are occasions when the usual self incompatibility in at least some heterostylous species no longer works. However, this raises the question of how many seedling will need to be grown to reproductive size to find perhaps very rare self-fertile specimens.

http://www.yorku.ca/shore/Shore%20%26%20Barrett%201986%20Can%20J%20Genet%20cytol.pdf

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