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Pearling and nutrient deficiencies - possible?

JoshP12

JoshP12

Member
Joined
8 Dec 2019
Messages
1,056
Location
Canada
Hi all,

I was just wondering what would happen in the following scenario:

1) You have a tank (co2 injected, dosing etc)
2) You have excellent growth, and your plants develop beautiful pearls all throughout the photo period.
3) You cease dosing a nutrient entirely (pick your favorite) and you magically suck all of that nutrient OUT of the tank. Suppose its nitrogen and you remove all of it and do not let any get dosed the next day even from decay, bacteria, whatever.

My question: Will the plants pearl?

In other words, is pearling an indicator that your dosing regime is providing the appropriate nutrients for a particularly plant at that particular distance from the light at that particular point in the tank? ** .... of course good growth without pearling is possible - but in this circumstance what would happen.

Cheers,
Josh
 
This experiment is somewhat easy to do in a bare bottom tank, epiphytic plants with virtually no substrate. DO IT!
 
Thanks for the link, @ceg4048.

You mention this: In turn, the photosynthetic rate depends on many factors such as light intensity, CO2 availability, nutrient availability, temperature and overall plant health.

I guess it leads to the crux of my question. Can we prevent this by limiting a nutrient?

What order does this "stuff" happen?

1) Photosynthesis gives energy via CO2 + light + Calvin cycle ... what nutrient (or lack of) BLOCKS photosynthesis from happening (certainly light, co2, but ... what about zinc?)?

2) The energy is used to then make tissues and at this point, I would think we need the macros and the sugar formed from photosynthesis.

Is 2 always happening? I think it is - since I see the plants grow during the day.

Of course 1 happens during the photoperiod.

With all that, however, in a system with ONLY high CO2 and light (enough), we should be able to force pearling (in the absence of nutrients) as it is merely a product of oxygen evolution ... which is formed via photosynthesis.

.... if we can't, then pearling is not a good indicator of dosing regime. The only indicator would be healthy plant growth.

Please weigh in!

Cheers,
Josh
 
After some looking into photosynthesis, I have learned this:

Photosynthesis is broken into the

1) light dependent reactions:

... consist of Photosystem 2 (PS2) and Photosystem 1 (PS1) where PS2 sole responsibility is to absorb light and generate ATP (which requires a phosphate group) and NADPH - during this process, an electron is excited in chlorophyll (found in Thylakoid -which actually change orientation depending on light availability) and liberate it into the electron transport chain, moving it around to trigger several processes. That electron is replaced via < photolysis > which does not use CO2. As a result, pearling is merely an indicator that chlorophyll antennae are absorbing photons of light, exciting and donating chlorophyll electrons to the ETC, and photolysis is occuring to replace those electrons.

As a result, I think we will have the following:

Given a healthy leaf, high light and filter off = pearling regardless of anything


To test this, we should acknowledge * and ** and to do so, I am going to leave the plant out for a day or two and see if it continues to pearl. Nonetheless, it will die as the light independent reactions won't be able to keep up at some point.

*The photo below is a leaf from a weed (weighed down by rocks) in my backyard in a cup of "aged", equilibrated (with air), and dechlorinated tap water. It is pearling and certainly does not have aquatic tissue - i.e. cannot sequester CO2 or other nutrients as effectively as our submerged plants from the water column (however, it may have some CO2 stored within its leaf? and certainly has nutrients in its vacuole**).


1595603228254.png

2) light independent reactions:
Calvin cycle where we generate sugar with CO2, ADP and NADP+ are regenerated.

Not much details in this post - will compile my thoughts all together at some point.

Josh
 
Day 2:

I attached a photo.

I should have used distilled water and there are lots
Of issues with this - but let’s see if it stops pearling.

With my new thoughts on phosphate, I am wondering if phosphate + light actually control pearling.

This leaf still has lots of stores food, so let’s see what happens in a week or so when it runs out.
 

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Day 3: was overcast today (see my experiment sucks 😛) but it is still pearling. And it is deteriorating.It has also become thinner. But still pearling. Now I think the Day 1 leaf is not the same leaf (I think my dish got tipped and the leaf was exposed to air again, so I ditched it). So call this the real day 2.

1595810175811.png
 
rebel said:
What sort of plant is this?
Click to expand...

I just found it in my backyard. It was off of a weed. I chose it so that it would struggle submersed - it doesn't have the ability (yet) to pull nutrients from the water column. So I dunked it under water and watched it pearl (only on the use of stored nutrients - assuming that it can't yet pull enough) ... obviously it can pull some - that's where I said I should have used distilled water.

@dw1305 would know way better.

1595858452559.png

Josh
 
With the entirety of < this thread > and embracing the cyclic nature of plant growth pearling is a sign that there is healthy chlorophyll. This means that pearling on new growth is definitely a great sign! Aside from a visual inspection of new growth to tell us if it is healthy - pearling is another visual cue for us. The presence of those oxygen bubbles means that all of the necessary nutrients required to perform photolysis + create chlorophyll were present.

No, don't chase pearling.

But I think if new growth is pearling, we can be rest assured that we are doing something right (that doesn't mean that no pearling means we are doing it wrong)!

Cheers,
Josh

P.S. I am not sure if we cam jam photolysis in healthy growth; however, I think that if we start with a healthy plant and blast it with light and starve it of all nutrients in the water column, it will pearl until it dies.
 
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