Plant Cuticle or: where the algae attaches. Research review paper

[Tom Barr]

http://www.plantstress.com/Articles/up_general_files/Stress and cuticular wax.pdf

Of note, CO2 and the % of CO2 used for cutin production.
Seems like this material can be sloughed off as diatoms and other algae grow on this non living EW layer. This may explain the long term lack of algae on some longer lived leaves, as well as microinvertebrate herbivores and large algae herbiviores.

Most aquatic weeds simple drop or aloow the leaves to get covered with algae epiphytes and grow faster and new fresh leaves instead of sticking around a fighting the problem. We prune the nice fresh tips and toss the old alage covered lower older sections.

So CO2 it's stability might be a key factor in the algae free state of many plants.
Mostly via good growth/trimming but perhaps via the cutin itself.

A poor/weak, cutin layer might make a good place for a spore to recruit and grow without getting sloughed off. Same for fungal attack on plant leaves etc.

Anubias and many other susceptible algae prone plants have cutin layers, whereas things like Egeria are lacking significant cutin. One might slough off, whereas one species might just outgrow the algae.

Regards,
Tom Barr

 

[Biollante]

Holy Decarbonylation Pathways, Batman...

Hi Tom,

Too cool!

Times like this when I wish I had a coherent central nervous system... Opposable thumbs would be nice as well.

Thanks,
Biollante

 

[borman]

Thanks Tom, very informative paper work..
so once again it confirm lead role of CO2...

Regards
Larry

 

[Tom Barr]

Well a bit like your skin that sloughs off the dead skin on the top and the new living skin under neath replaces it.
At the whole plant level, leaves simply drop and are replaced by new runners/new growth at the tip of meristem.
Why bother replacing it if it's easier to simple grow a new leaf that's closer to the surface/light/CO2?

You can have several mechanisms to avoid algae, herbivores at the micro scale are yet another not noticed by aquarist
Current knocking it off, lower light tolerances etc.

Regards,
Tom Barr

 

[Philosophos]

Thanks Tom, I've been looking for good details/confirmation that ephiphytic wax sloughs and regrow in a way meaningful to algae. This paper gives some very nice details on the process; as usual it's over my head in places but that encourages me to learn a little more.

I'm wondering how far cuticles are reduced on submerged marophytes though, and how much that impacts EW production.

I know allelopathy is a swear word around here, but phenol concentrations within the waxes also comes to mind. I'm going to have to get my hands on these two papers someday:
http://www.jstor.org/pss/3547551
http://www3.interscience.wiley.com/journal/112657971/abstract?CRETRY=1&SRETRY=0

 

[Tom Barr]

Well, allelopathic compounds imbedded in the cutin layer, now that makes more sense as far as reduced algae recruitment.

Adding AC would not have any effect on them there.
Nor would they get washed away.
They'd have to be stuck on a healthy leaf, but be released on a not so healthy leaf and thereby alloow algae recruitment to occur.

That I could speculate. The other?
No, I see little evidence.

Some plants also seem to get algae and others do not near as much, this would explain it in the chemical context.
But you'd need a plant that does not product this compound and have it localized at the EW layer.
A molecular approach using a knock out mutant and 35s promoter+ a GFP to the protein that deposits this would be a potential way to see and verify.
Got 200K$?

Regards,
Tom Barr

 

[Crispino Ramos]

I want to share what I read about plant cuticle (link) - http://en.wikipedia.org/wiki/Plant_cuticle

 

[Philosophos]

If the EW degrades on unhealthy leaves then there would simply be no way to retain a meaningful concentration of AC's. Being that phenols are based on carbonic acid, it'd follow that production for it would crash with carbon deficiency just as cuticle formation would. You probably realize this, but I figure it doesn't hurt to narrate along for those who don't spend time reading about this stuff in detail.

The last time I brought this up you said it was unlikely that so many species of algae would be harmed by a handful of compounds. I still don't know enough about phenols to respond to this outside of speculating a little about oxidization, but phenol toxicity would be something I'm trying to find better information on.

As usual though, money thwarts the whole thing being tested well enough to make a meaningful statement that would change the hobby. I'll get back to you about this in 20 years or so?

 

[Tom Barr]

As far as imbedded protection from pathogens or epiphytes, I'd say this is much more likely than chemicals just released out into the water column.........to only be washed away....... and much easier to change and alter as conditions change.
I'm not saying it's right or wrong...........

So the methods of detection need to reconsidered greatly.

Aslo, there is certainly selectivity in plants that are much more prone to algae epiphytes than others.
This may be related to their ability to acquire and sequester carbon as CO2 in a mixed community.
Some plants will still grow pretty well and not get any algae, others will very quickly in the same tank.

So it might be a two part issue occuring, both CO2 uptake/competition for CO2 and some ability differences with prevention of epiphytes from the EW layer.
There are holes in this EW layer BTW, it's got weak spots and that's where most of these things attach.

I'd suggest there's more weak spots on a CO2 limited plant that a non limited plant.

Regards,
Tom Barr