Plant growth question

1792 Views 14 Replies 6 Participants Last post by Zapins, Jan 9, 2009

mex2tx

Discussion Starter · Jan 2, 2009

During my experiment,Being new to aquatic plants, i thought that if i cut parts of them it
will damage them.Now,I know this is false.

I was dealing with anacharis.

Now my question is:
If aquatic plants(anacharis,to be exact) are measured will it make a difference to its average plant growth compared to other anacharis plants?

For example,
I started 6 plants,unfortunately with different start heights because of the reason i just noted.
They were: 18.4 cm,20.1cm,18.6cm,20.1cm,19.3cm,and 18.6cm.

They ended up with:
19.6cm,19.7cm,14.7cm,24.7cm,23.9cm,and 21cm.

So, obviously i couldn't form a conclusion or analysis based on that because others had a higher start height. I decided to do it on average plant growth between measuring periods,i.e day1 to day3, day5 to day7 so it would be fair.

With that in mind ,would higher heights affect its plant growth?
Would a 20 cm plant have a higher avg. plant growth than a 18 cm plant?

This is really crucial to my project and any help would be appreciated, if you need more information
please ask.

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cbwmn

· #2 · Jan 2, 2009

Mex2
What are you trying to achieve?
I don't understand your experiment.
I have a 46G w/2 WPG cfl, and EI ferts. DIY CO2.
I have Ludwigia Repens, Hygrophilia Polysperma “Sunset” and Limnophilia Sessifolia
that grow 2 – 4 inches in a week.
When I had Anacharas it grew at about the same pace or maybe even faster.
I have to trim and replant stems often.
What are you water parameters & lighting levels?

Charles

davemonkey

· #3 · Jan 2, 2009

I'm not clear what you are looking for, but here is my take on it:

In general, a taller plant will grow faster than a shorter plant of the same species because it will be closer to the light source. The taller the plant gets, the faster it grows. (Of coarse, that's if teh light source is at the top and there are enough nutrients there to support the growth. )

If you are measuring the difference between uncut plants and cut plants, you could cut all you r current plants in half. Make the "bottoms" all the same hight by cutting them evenly across the top. Then, make all the "tops" even by cutting them evenly across the bottom.

That way, you have a group of all bottoms that are equal, and a group of all tops that are equal. And the tops and bottoms are also equal to each other in height. Plant them all at the same depth and let them grow.

My opinion is that you will find the tops growing faster, but as single stems. The bottoms will grow slower, but will have more than 1 growing point (form a bush, so to speak) .

-Dave

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mex2tx

Discussion Starter · #4 · Jan 2, 2009

My purpose is another thing that has its own thread somewhere else in this forum....

It is will pharmaceuticals affect plant growth? I have finished , but before i form a conclusion i need to know if the heights of the taller plants affected its avg. plant growth from a day to day basis.Because i started them off at different heights.

So since saying that the pharmaceuticals had and effect on plants ABC because they did not grow to the height of plants DEF would be inaccurate since they started off at different heights. So i will base it on average plant growth from a day to day basis.

davemonkey

· #5 · Jan 2, 2009

Oh, sweet! I remember that thread! I look forward to seeing your results.

-Dave

HeyPK

· #6 · Jan 2, 2009

Instead of measuring the length increase, which is a very poor measurement of growth, you should measure weight gain. Wet weight can be measured by swinging off or blotting off attached water. I have done that by putting the plant in the middle of about a three foot strip of cheese cloth, folding it back and swinging it around. You can start with a number of small plants, get their wet weights, or, better, their aggregate wet weight, growing them under the experimental or control conditions, and then getting their wet weights again.

Dry weights are even better measurements of growth than wet weights, but you can't get the dry weights of starter plants because then they are dead and you can't start them. You could get a large bunch of starter plants, divide them in half, get the wet weights of each half, plant one half and dry out the other half and then calculate the dry weight of the planted half by assuming that the fraction you multiply the the wet weight to get the dry weight would be the same in both halves.

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mex2tx

Discussion Starter · #7 · Jan 3, 2009

HeyPK said:
Instead of measuring the length increase, which is a very poor measurement of growth, you should measure weight gain. Wet weight can be measured by swinging off or blotting off attached water. I have done that by putting the plant in the middle of about a three foot strip of cheese cloth, folding it back and swinging it around. You can start with a number of small plants, get their wet weights, or, better, their aggregate wet weight, growing them under the experimental or control conditions, and then getting their wet weights again.

Dry weights are even better measurements of growth than wet weights, but you can't get the dry weights of starter plants because then they are dead and you can't start them. You could get a large bunch of starter plants, divide them in half, get the wet weights of each half, plant one half and dry out the other half and then calculate the dry weight of the planted half by assuming that the fraction you multiply the the wet weight to get the dry weight would be the same in both halves.

Although i like the idea, its too late to be swinging them over at me.
The experiment was done about 2 months ago and is due in 14-15 days.
I had a thread that , months ago, you could have suggested this, but i need to start on my conclusion. Thanks, though . Much appreciation...

mex2tx

Discussion Starter · #8 · Jan 3, 2009

12

davemonkey said:
Oh, sweet! I remember that thread! I look forward to seeing your results.

-Dave

I think i posted pictures, but ill post them again.
Tank 1(how it looked when i added pharmaceuticals

After a couple of days

Although they had a shorter avg. plant growth, they were the first ones to sprout

TANK 2:

BOTH

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HeyPK

· #9 · Jan 3, 2009

It looks like a lot of the plant died in the tank with added pharmaceuticals. The plants are definitely healthier in tank 2. I would subtract the dead growth from the orighnal lengths. The fact that the sprouts grew in tank 1 may be due to the pharmaceuticals being destroyed by bacteria after a while, and thus, the parts of the plant not originally killed were able to grow.

davemonkey

· #10 · Jan 4, 2009

HeyPK said:
It looks like a lot of the plant died in the tank with added pharmaceuticals. The plants are definitely healthier in tank 2. I would subtract the dead growth from the orighnal lengths. The fact that the sprouts grew in tank 1 may be due to the pharmaceuticals being destroyed by bacteria after a while, and thus, the parts of the plant not originally killed were able to grow.

Ditto. The chemicals definitely had a huge negative effect on Tank 1.

-dave

mex2tx

Discussion Starter · #11 · Jan 6, 2009

davemonkey said:
I'm not clear what you are looking for, but here is my take on it:

In general, a taller plant will grow faster than a shorter plant of the same species because it will be closer to the light source. The taller the plant gets, the faster it grows. (Of coarse, that's if teh light source is at the top and there are enough nutrients there to support the growth. )

If you are measuring the difference between uncut plants and cut plants, you could cut all you r current plants in half. Make the "bottoms" all the same hight by cutting them evenly across the top. Then, make all the "tops" even by cutting them evenly across the bottom.

That way, you have a group of all bottoms that are equal, and a group of all tops that are equal. And the tops and bottoms are also equal to each other in height. Plant them all at the same depth and let them grow.

My opinion is that you will find the tops growing faster, but as single stems. The bottoms will grow slower, but will have more than 1 growing point (form a bush, so to speak) .

-Dave

Dave, you are great and you will probably end up a part of my project. Although you will be referred to as " a source from Aquatic Plant Central". I'm too lethargic to type up exact numbers. But would you agree,in general, that if a 7 inch tank, had 3 plants(that bent because of their limitations) with 7.25,7.5, and 7.65(inches) as their heights they would have the same chance of growing as high as they can in that situation because they are all close enough to a light source that is 8.5 inches high?

Anyone can answer this. But remember it is a generality. I don't want a response contradicting about a specificity such as "no, because one is taller" I know one is taller , so it might have a better chance. Or "it depends on how wide the plant is." Assume they are all the same width.Its just Anacharis. but remember they are all taller than the tank , so they dont " stand up straight" they bend.
Therefore, they all have the same chance,as they are all receiving the same amount of light. Right?

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mex2tx

Discussion Starter · #12 · Jan 6, 2009

HeyPK said:
It looks like a lot of the plant died in the tank with added pharmaceuticals. The plants are definitely healthier in tank 2. I would subtract the dead growth from the orighnal lengths. The fact that the sprouts grew in tank 1 may be due to the pharmaceuticals being destroyed by bacteria after a while, and thus, the parts of the plant not originally killed were able to grow.

Could you clarify on that?
I'm not sure i understood.

I put in medicine every 3 days so I'm not sure if bacteria can work that fast.:laser:

Bert H

· #13 · Jan 6, 2009

mex2tx said:
Could you clarify on that?
I'm not sure i understood.

I put in medicine every 3 days so I'm not sure if bacteria can work that fast.:laser:

Bacterial doubling times are measured in hours, so, yes, bacterial effects would definitely be felt in that time frame.

mex2tx

Discussion Starter · #14 · Jan 9, 2009

Bert H said:
Bacterial doubling times are measured in hours, so, yes, bacterial effects would definitely be felt in that time frame.

Interesting, we haven't really touched on that subject..

Zapins

· #15 · Jan 9, 2009

Some bacterial doubling times are measured in minutes (roughly 30 minutes).

They multiply very quickly!

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