Why do some wistuba Heli never seem to go beyond junvenile stage?

[fly-catchers]

Why do some wistuba Heli never seem to go beyond juvenile stage?

I have been growing Heli from Wistuba since 1997 but have found some clones (for me at least) never progress well. My hispida never did and got smaller. Yet another clone from elsewhere moved to adult growth quickly. My 10 year plus elongata is tiny and just produces endless offshoots which I eventually split off. But none go beyond the tiny juvenile stage. The same with my neblinae x hispida. And a recently purchased parva which had two adult pitchers but had reverted back to small juvenile growth prior to sending to me is continuing this trend of just producing offshoots and not getting bigger.
Andreas best plants came from the 2004 period where stage 3 as well as stage 2 was often offered and they continued to produce strong adult growth. Now stage 3 plants are rarely offered and they just basal like mad! Something in the chemicals used for the TC perhaps?

Any suggestions as to kick start any adult growth? I use Trichoderma atroviride and once established Maxsea.

cheers

bill

 

[mikewilder]

Hello Bill,

I and several other growers have observed similar problems with perpetual juveniles, especially H. elongata. I hypothesized that the cytokinins used for multiplication might have caused DNA methylation changes that would cause the plants to stay small and multiply for years ex vitro. I think this account is a plausible explanation, but that doesn't make it true.

If this were the explanation, since auxins can be antagonistic to cytokinins, I hypothesized that applying an auxin solution ex vitro might undo the methylation changes and allow the plant to get on with it and make adult leaves. After admittedly very limited testing along these lines, I and another grower did not see any improvement after applying an auxin solution ex vitro. However many more auxins, at different doses, could be tried. So these ideas are debatable at best, I do not know how to "fix" the problem.

I also multiply my own plants in vitro, using cytokinins, and I have not observed this perpetual juvenile behavior so far. This is true even for genotypes that had been in multiplication for 5 years or more. So if the mechanism I have described is in play, it must be very much dependant upon the taxon and the specific amounts and/or ratios of the specific hormones used.

I mentioned my hypotheses to Andreas W some time ago. He agreed elongata was a bear, but said he had observed clumps of juveniles in habitat. He believes the extended clumping time of juveniles is a natural phenomenon unrelated to in vitro multiplication. I don't really have specific evidence that could contradict this idea.

The more I discussed this matter with him and other growers, the more I became interested in the fundamental question: how does a normal Heliamphora seedling "know" to start producing adult leaves? In a general way we know that organogenesis can be manipulated with hormones. But I think it remains mysterious why, after x number of years, a plant stops producing juvenile leaves and starts producing adult. I don't really know much about plant physiology, there may be relevant info in the literature. If we had a model for how the plant normally switches to adult leaves, potentially we could manipulate it. The general problem I face is that I no longer have access to good journals, generally when I find a promising looking paper abstract I'm not able to actually get the paper. YMMV.

 

[killerplantsguy]

I read this with much interest. I've been growing a H. elongata for about seven years and have never seen adult pitchers.
It's been frustrating, but misery loves company...
Cheers.
Paul

 

[BigBella]

I have also experienced that same same phenomena with H. elongata -- mine, after more than six years, but not with any other species; and I have not witnessed that condition with any of my plants in micropropagation either. I have noticed, though, that some species of mature Heliamphora, if stressed -- especially by higher nighttime temperatures -- will revert to the production of juvenile leaves for a period of time . . .

 

[fly-catchers]

Thanks for the interesting thread response Mike. Its good to hear my elongata is not alone!!
So far my most vigorous Heli have come from another German who sells usually only seed grown plants or divisions from his own seed grown mother plants. I noticed that some early Sarracenia I also got from Andreas in 1997 which I guess where also TC had the same over production of basals and just produced tiny pitchers. But many years on are now growing like all my other Sarracenia with good strong pitchers.