Show us those cool leaves

[helixturnhelix]

Hi Charlie,

Any promising seedlings that are in propagation mode that have the multi-lobed leaves?  These are becoming my new favorites Also how do they vary from CV to CV?  Pinot Noir looks similar to a fig leaf whereas african princess has very deeply lobed pointy leaves.  It looks as though the foliage in the pic you posted of that CCacao x Night Runner seedling is even different yet!

[Charlie]

I agree about the cool leaves, Chris. I find them quite interesting and they do create a different look to the plants that is nice even when they are not blooming. You described the differences between them well. The leaves can be almost solid with small indentations that create 2 separate areas, or they can look a lot like Maple leaves with more pronounced indentations, or they can have such extreme indentations that the leaves appear to have fingers or just about anything in between these types is also possible.

There are a lot of new seedlings that have kept these unusual leaves up to first flower. Normally, we expect them to revert to normal hibiscus leaves by first flower but in some cases the change can come after first flower. I forget which one it was, but I recently saw a flower on a seedling bush that showed the unusual leaves on the lower 4/5 of the plant but normal leaves on the top 1/5. That tells me that the plants propagated from cuttings of that seedling plant will have normal leaves.

My best guess at this time is that the original 4 varieties that we had last year that kept the unusual leaf forms will increase to at least 12 varieties available this year that also show the cool leaf forms. I won't know for sure which ones until I see the cutting grown plants.

Charlie

[helixturnhelix]

Thats great Charlie!  I would love to see some pics of these new varieties if you got them.  Adding interest to a non blooming plant by having interesting foliage is really great.  These new seedlings you have are really interesting.  I think it would be cool to start crossing these varieties to one another and see what variation we get in the offspring.  I have a feeling that this is a dominant trait and both Key Lime Pie, CCacao are both heterozygous.  That you only need one gene copy to have the multi-lobed leaves.  If this is indeed true then crossing CCacao to one of its multilobed offspring should yeild almost all multilobed.  It is more likely more complex than this, but it would be easy to determine based on the offspring from crosses like those.  Perhaps you already have some in the works? 

[Pachrian]

Chris, here's a pic of my Arabian Princess (CCacao x Moon Madness). I love those leaves. Good thing too because they are pretty big

[Charlie]

Hmmm, very interesting. I think I have some CCacao x Pinot Noir seeds which would qualify. Not sure if they are planted yet. Despite the record number of seedlings growing I'm about 1000 seeds behind in planting. Bumper crop this year as I decided it was time to concentrate on hybridizing again, this time using all good rooters and good bushes to see what would come of it.

Anyway, I think there is a good chance you are right about this, since more or less half the offspring of CCacao show this trait, at least in the beginning.

Charlie

[Charlie]

Very nice, Uli. I think you will like the flowers, too. There are a lot of subtle shades of color in them, hard to capture in photos. Fairly large and well formed, too.

Charlie

[Pachrian]

I can't wait...but I fear I have to. Borers on this one too

[Charlie]

Chris, here are 3 of the new ones with unusual leaves. Note that one of them is Saffron x Black Dragon, no CCacao in its heritage. I would expect this one to revert to normal leaves before first bloom but it hasn't so we shall see. I am getting first bloom in less than a year so it may be that leaf reversion is related to plant maturity and first bloom can come before or after the leaves revert. Nonetheless, it is interesting and I am holding out some hope for this one to keep these very indented leaves.

Charlie

[Charlie]

Uli, I am wondering if this type of moth has been visiting all your plants. I don't know for a fact but I don't see how they can consume tissues inside the stem without taking in plant sap. I suppose they could have a way of drilling that does not involve eating but then what would the larvae find to eat inside the stem? If they do consume plant sap then a systemic like Bayer Tree and Shrub or Safari should kill these creatures. If you have either one I suggest treating all your hibiscus with it (Safari preferred).

Charlie

[Pachrian]

Charlie, I will go shopping once I cut open the AP leaf and take pics of the findings (see the other thread)

This moth is definitely going too far

[helixturnhelix]

Great looking AP, too bad its having caterpillar issues.

Charlie, that BD x S seedling is really really cool.  I like everything about it, the leaves, the flower and the fact that it is not a CCacao offspring.  I really hope that it keeps those leaves because they are really cool.  Hopefully the wood will be mature enough soon to root!  I also like the other two because they look alot like maple leaves.  This is exactly why polyploid plants are so cool to hybridize with, because of the amount of variation you can experience with each seedling.

 I am going to have to do some research on leaf development, but if I am remembering correctly the shape of leaves are determined by very precise apoptotic (cell death) signals that tell certain cells to die or live.  This gives the leaf its shape, but I really need to see which genes are responsible for these signals.  Chances are that they have been worked out in arabidopsis, which is the plant most genetic manipulation is carried out in and usually the mechanism is conserved across plant species.  Alas to the books! 

[helixturnhelix]

Ah ha!  I found a paper that determined the likely genes involved in leaf serrations.  There is so much scientific jargon in the paper, but what is cool is the staining pics they have.  Where they stain for expression of a specific gene and you can see where it is localized in developing leaves and how it relates to what the mature leaf looks like.  What is crazy to me is the second picture which shows varying amounts of NAM1/CUC3 expression and how the top most picture looks similar to what we are seeing in the hibiscus leaves.  Where this gene is turned off, there are smooth leaves (normal hibiscus) but when it is expressed at a medium level (the middle pic) its leaves look alot like those of Pinot Noir.  Finally looking at the high expression you see really indented and serrated leaves, which look alot like that CCacao x Nightrunner seedling.  I was really shocked that the pics of the mutant arabidopsis looks just like the seedlings!  So it looks like in these select few seedlings this NAM1/CUC3 gene that is normally turned off, is getting turned on.     

You can find the paper here.
http://www.sciencemag.org/cgi/content/full/322/5909/1835

and the figure I am talking about is attached.

[Charlie]

Chris, that is really fascinating.

Would you say that the gene that is normally turned off is a later development in the evolution of plants? I am looking for a rationale to call the most deeply serrated leaves "primitive", a remark that has floated around the hibiscus community for many years. It didn't make sense in terms of the types of leaves that the ancestral species of hibiscus show but perhaps it makes some kind of sense in the evolution of leaves in general.

It's kind of confusing knowing how to think of this in terms of hibiscus hybridizing. Might a mutation or flaw in the genes of Key Lime Pie caused it to lose this gene or deactivate it so that that cultivar shows a type of leaf not seen even in the original hibiscus species that are ancestral to our hybrids? These leaves are commonly seen in young hibiscus seedlings though, so what does that mean? That this gene is not expressed until maturity in some hybrids?

Interesting, in any case! I feel a newsletter article starting to develop here 

Charlie

[helixturnhelix]

Hi Charlie,

I would say that certain genes are turned on an off depending on how an organism adapts over time.  I think that calling these serrated leaves primitive is not too far from the truth.  It seems to me that these genes were no longer needed and turned off creating leaves without serrations.  This might have been to increase the surface area to capture more light, or as a product of the species moving from temperate to more tropical environments.  (hardy hibiscus all have serrated leaves)  But even if these genes are not active, they are still in the genome of the plant.  When those genes are suddenly turned on (mutation), the leaves become serrated.  Take for example fruit flies they normally have two wings, but when a certain dormant gene is turned on via genetic manipulation or mutation these flies suddenly have four wings.  This seems to be the primitive wing type (think dragonfly) and when the flies became more evolved this gene was no longer needed since two wings was more evolutionarily favorable.  

This is probably the case in hibiscus as well.  It is hard to say because it seems as though many genes are involved in leaf development.  I do have an idea as to why these leaves change before flowering.  According to some reading I was doing it seems as though the regulation of genes that control leaf and flower development are very close.  I am thinking that the que to produce flowers some how turns off this gene for serrated leaves and produces the non-serrated types.  Now evolutionarily it might be advantageous for juvenile plants to have different leaf types in order to adapt to many different environments (depending on where their seed germinates)  However, once its time to flower the plant doesn't have a reason to continue to have this gene on (for one reason or another) and turns it off.  Flowering is really the plants terminal goal, so once it is able to reproduce it might turn off unnecessary genes like this one for serrated leaves.  In some individuals this leaf type might have helped them survive in a specific location and therefore will stay on even after flowering.  

This is of course all speculative, but I like the way it fits together      

[Charlie]

Chris, somewhere you asked to see the leaves of one of the Fascinating Foliage varieties - Wakanisha topic I think. Since I found photos of more varieties than Wakanisha, below are photos of 3 of these varieties - Wakanisha, Raindrop, and an unnamed seedling. These are young plants growing in 6 inch pots after being rooted from wood cut from the original seedling.

Charlie