Hygo Polysperma Leaves drooping

[scottward]

I have a 72" x 18" x 20" tank. Currently I am running 3 rows of T8 lighting, 2 Eheim 2217 canisters, CO2 via AM1000 and dedicated pump (Ocean Runner).

Dosing is as follows:

Sat/Mon/Wed - 1 tsp Potassium Nitrate + 1 tsp Mono-Potasisum Phosphate
Sun/Tue/Thu - 30mls Rexolin APN trace + 30mls EDTA iron

I can provide more details about the traces/iron mix if necessary.

CO2 comes on at 1pm and goes off at 10pm.
Lights come on at 2pm and goes off at 11pm.

What I've noticed is that my Hygro Polysperma leaves start to droop quite a lot mid-morning (say around 11am ish). There is no CO2 or lights on at this time.

Attached is a photo showing the drooping.

Several hours into the photoperiod, the leaves straighten out and look normal again, and by the end of the photo period, the leaves look perfectly normal.

What causes this?

Scott.

 

[scottward]

Please help!

 

[Tom Barr]

Sounds like some Nyctinasty. I have not kept it due to being a weed.

 

[scottward]

Thanks Tom!

I wonder why it is occurring mid morning in my setup?

Googling nyctinasty shows that it is a plant response at the onset of darkness - it's hardly the onset of darkness around 11am and there is a reasonable amount of ambient light in the room at that time.

I don't like how the leaves are all limp for the first part of the photoperiod.

How can I fix this short of getting different plants?

Ambient room light changes?

 

[scottward]

Hmmmm. I have a theory about this and would be very interested in others thoughts.....

My planted tank is located on the same side of the house where the sun rises in the morning....

What this means is that the ambient lighting in the morning gradually increases from dawn through to about 11am ish, then, as the sun moves over the house and to the other side, the ambient lighting in the room starts to drop a bit.

I wonder if this drop in ambient light as a result of the sun's movement is somehow tricking the plant into thinking that it's about to get dark and hence they are folding their leaves downwards in preparation??

When I look into the tank very early in the morning, the leaves are folded upwards slightly, not downward. This is after the tank has been in pitch black darkness all night.

I believe that nyctinasty is about a plant preparing for *impending* darkness, which is not the same as what a plant would do if it were to suddenly become dark? So I wonder if the plant leaves droop down because they "have more notice" so to speak...?

This is really weird.

I've spoken to gurus on other forums and they concur with Tom that it is some kind of nyctinastic movement.....

It's weird though that nobody else has asked this question before, only me, so there must either be something very unique about my setup or that others give up and get new plants instead of persisting to ask why.

Bio - any thoughts mate?

Scott.

 

[Tom Barr]

My red ludwigia in the 120 does this sometimes, particularly after a trim.

 

[scottward]

My red ludwigia in the 120 does this sometimes, particularly after a trim.

Ok.

I'm not doing any trimming in my tank when this occurs.

I have to do some more reading, but aren't there some kind of little water filled sacks/hinges at each leaf/stem junction? Can trimming/nyctinasty have something in common with this region of the plant?

Scott.

 

[scottward]

I really hate this nyctinasty! The hygro is otherwise growing really well.

Half of me wants to rip it out half of me wants to leave it.

Tom mentioned his ludigia does this after a trim.

I'm wracking my brain trying to figure out how I can fix it...

 

[scottward]

Hmmm. Any experts on turgor pressure ?

 

[scottward]

Come on gurus......

Plasmolysis ??? Is this what is happening to my plants?

 

[dutchy]

First check at what time in the morning the leaves are still in normal position during the lights off period. Then increase the photoperiod accordingly, so turn the lights on earlier. That should do it.

 

[scottward]

Hey dutchy.

Yeah, I thought of doing that. My lights currently come on at 2pm and go off at 11pm.

The wilting starts around about 11am. Possibly if I shuffle my light period ahead I could have the lights go on at around 11am, and then off at 8pm, so the same photoperiod, but the problem then is that the lights are on during the day more when I am not home (and obviously on for less time when I am home). I could extent the photo period a bit, but I'm worried that might cause some issues itself....

I'm really starting to wonder whether this is really nyctinasty...

Tom mentioned he sees this kind of thing in some of his plants after a trim....

I wonder if there is something wrong with the water in my tank or in the tissues of the plants that is causing this...

I've been reading that plant leaves can droop if there is insufficient water being pumped into the cells, and also when there is too much water being pumped into the plant cells (whereby the leaves become "heavy" and this can cause them to droop - but this might only apply to emersed growth)...

It's all to do with salt balances etc (I think).

Could it be because I dose too little/too much of something in particular? I dose Full EI for my size tank, so I strongly doubt it would be P or N, K seems unlikely also (I don't dose this independantly).

Mg? Ca? Cu?

I think it is going to take me a while to work this one out...

Only the new growth at the top seems affected, lower leaves don't droop....

If it were nyctinasty - surely every single leaf would droop?????

Scott.

 

[scottward]

Check out this: http://en.wikipedia.org/wiki/Pulvinus

I wonder if I have a K issue? I dose 1 tsp Potassium Nitrate and 1 tsp Potassium Mono Phosphate 3x per week (into 100g). This should provide plenty of Potassium also - correct?

Flipping this around the other way, is it possible that I have too much K and this is messing with the Pulvinus in some way?

Clutching at straws a bit I know...my tank is looking really good apart from this stupid issue with the Hygro leaves. There must be something extremely unique about my tank, as everybody else reports leaves folding up, not down. Leaves folded up probably look ok, leaves folded down looks horrible!!!!!

Help!!!!!!!!!!!!!!!

Scott.

 

[mike]

Sat/Mon/Wed - 1 tsp Potassium Nitrate + 1 tsp Mono-Potasisum Phosphate.

That's a lot of Phosphate from KH2PO4!

According to my calculations you are adding about 30ppm per week. 1/8th of a tsp would be enough.

Mike

 

[scottward]

For a 100 gallon tank, standard EI is 1/2 tsp of K2HPO4, I doubled it some time ago as I think it was helping with some GSA.

I think 1/8 tsp would be nowhere near enough???

Nevertheless, is it possible I may be dosing too much K as a result?

I know Tom experimented with high levels of K in the past, but perhaps not with this particular plant which is the only one drooping its leaves...

Dutchy, can you tell me more about your observations? Same plant, same symptoms?

If you google this, you won't find very much at all, just leaves that fold up....not droop down!

Scott.

 

[dutchy]

Same symptoms, different plants, like Ludwigia and P. erectus. You might see that an hour before lights on the leaves are still straight. Then adjust lights accordingly. You can see the difference the next day already.

This is NOT a nutrient problem.

 

[scottward]

Thanks Dutchy.

I'll have to put my lights on a good 3 hours earlier, and CO2 of course. It's looking like I don't have any choice...could toss this species of plant.

What I really don't get is why isn't this issue more common? If I google it I find my own posts on this site!!

...and why does Toms ludigia do this after a trim, nothing to do with nyctinasty...?

I can't connect the dots.

 

[dutchy]

Maybe it IS nyctinasty, and the lack of light is forcing the plant to move it's leaves further downwards trying to get some light. I noticed that it happens when ambient light is incresing while lights are still off.

A lot of plants adjust their leaf postition according to the light available. You can also see this in Bolbitis heudelotti. In low light the leaves grow almost horizontal, while in high light they can be standing up at a 45 degree angle.

At the time it happened in my tank all the leaves were already "open", even though lights were off, just because of ambient light. You might be able to cure it by preventing ambient light coming in. In my case the ambient light was only 12 micromols of PAR.

Every plant has different needs, so not all plants will show the same behaviour.

Anyway advancing the photoperiod cures it.

 

[Asmack Arabia]

i would like to comment on this because i had the same experience before with my hygrophila plant. and from what i observed, it has something to do with the photoperiod of the plants. it seems the hygrophila can distinguish the natural day and night time it is in. starting the artificial light much later during the day, say 11 am, causes stress on the plant which makes it droop its leaves. but starting the artificial light closer to the natural daytime seems to cure this problem.

 

[scottward]

Thanks guys, I will adjust my photoperiod.

Can I go from 2pm lights on - 11pm lights off to 11am lights on - 11pm lights off in one go, or do you think I should add more gradually? I can't see any problem provided I bring the Co2 on time ahead accordingly.

I don't want to have the lights switch off at 8pm though, I wouldn't then see much of my tank when I get home from work!

Unfortunately there is nothing I can do about the ambient room lighting during the morning.

Thanks guys, appreciate the help this one has been driving me nuts.