Plant Respiration

[arvin555]

I am posting this question here because I came upon the original info from waterplant keeping... not sure if terrestrial plants are the same, here it goes.

1. I read before that when there is light/daylight we inject CO2 in aquarium with water plants so they can use the CO2 for photosythesis. The take CO2 and expell O2.

And that at night you don't need to add CO2 because in fact the plants use up O2 at night and that they grow at night.

1a. Wonder if this is the same with Terrestrial plants?

2. I just read a book called ABC's of nature (1984). And what it said was interesting..... it said that all plants take in O2 just like other living things, and produce CO2, but the CO2 gets used for Photosythesis during the day time. At night because there is no Photosynthesis, then CO2 is released.

My question is:

Which one is correct?
1st one or 2nd one?

Because if the 2nd one is true, then plants can suffucate if we put them in a bag filled with CO2 only?

Reason I ask is CP related actually. I have some Sarracenia that suffer from scale insects, I plan to put them in a plastic bag and fill that with CO2 hoping that after maybe 4 hours of pure CO2 gas, they will all die (the insects).

TTFN
Arvin

[shawnintland]

Hi Arvin,

Good question! I DO know that I have read a thread about using Co2 to kill off parasitic bugs and the people discussing it said it worked great. They were talking about terrariums and/or setting plants inside a terrarium to do the job. I also think they were using chunks of dry ice as the co2 producer. Wish I could remember the link but...

[arvin555]

Thanks Shawn, I remember that Lim mentioned this to someone, maybe even suggested it to you or another member to rid of pests. I am almost sure that it will work specially if it is done for more than 4 hours.

However what got me curious is the book I recently read that said that plants actually use O2 and explell Co2 just like all other living things... etc. etc. very new to me!

TTFN
Arvin

[strath76]

Hi Arvin. Plants use CO2 during the day, and expell O2. This is reversed at night. Many years ago in hospitals they would remove flowers from hospital rooms at night as they thought the CO2 may have adverse effects on patients.

In actual affect the amount used and produced, especially in plants the size of CP's, is very small. Here in Australia CO2 is used in the fruit industry to protect crops that have been harvested from pests (mainly larger pests such as mice and rats).

The majority of plants synthesize 'food' in the same manor using the same pathway. These are called C3 plants. Some plants have adapted a slighlty different pathway that has some advantages over teh C3 pathway and these are C4 plants. An example of a C4 plant is Sugar Cane. Whilst the system is different they still rely on the same compounds. If you are really interested in this then check out C3 and C4 plants and also a thing called the Calvin Cycle.

[Robert]

Originally Posted by arvin555

Because if the 2nd one is true, then plants can suffucate if we put them in a bag filled with CO2 only?


TTFN
Arvin

Hi Arvin, putting plants into a concealed plastic bag we are creating a micro climate. The air inside always contained water,02,C02 and others.It becomes a cycle using CO2 during day and produce O2 and vice versa. Unless pure 02 or pure C02 was pumped into, depriving them of one vital living component, they will wither and die.

[Khoas]

The 02 don't come from the Carbon Dioxide but from the water brought up via the roots. The actual Carbon is used to make sugars. An interesting things is if you increase the CO2 around the plant it will increase the growth rates as well as kill any animals.
Israel has done experiments with 10% CO2 in a sealed greenhouse and the results were very impressive.

[poweramps]

C3 plants will respond to increase in ambient CO2 during daytime. This prevents to a certain degree photo-respiration especially if under conditions where stomata are partially closed (Ribulose bisphosphate + O2 = phosphoglycolate instead of RuBP + CO2 = phosphoglycerate). This is a common practice for some crops grown in greenhouses. C4 plants are adapted to high heat and will not benefit much from increase in CO2 since they incorporate CO2 via another pathway and they create their own CO2 rich environment in the photosynthetic cell. CAM plants fix CO2 at night, and close their stomata during daytime.

If we consider all living things with mitochondria, then they do do aerobic respiration, ie there is a need to produce ATP with O2 as the final electron acceptor. Just that in plants, the output O2 is more than enough to support the respiration.

[arvin555]

Thanks guys, I am a bit lost with the technical aspect, though some I understood a bit.

I would like to point out that I am not really asking if my plant will die if put in 100% CO2 environment for 4 hours, I think that answer basically is no... Right?

I was just wondering if it is true that plants (or some plants) do need to inspire O2 during the day, which means they do use O2 as well.... unless what Khoas said can be taken as a general rule that O2 is really needed but is taken from the water that is absorbed.

The post is really to update my (most) general concept of plants, that they take in CO2 and expell O2. Would it still be accurate? At least the CO2 intake is higher than the O2 intake and that the O2 expired will be higher in concetrantion than what was inspired or absorbed?

Still scratching my head, but will search for C3 and C4 later.

TTFN
Arvin

[arvin555]

Just came from googling, and basic info I got is that plants are aerobic and therefore inspire O2 and expire CO2... however this respiration is not really enough to fulfill the needs of the plant to produce or process food/energy... and therefore need more CO2, and a by product of the process is O2.

I hope this is correct, over simplified as it is.

TTFN
Arvin