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Interesting question during the oral exam about CO2 and reactive oxygen species(ROS)

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  • Interesting question during the oral exam about CO2 and reactive oxygen species(ROS)

    I had an interesting query: what would occur to a submersed aquatic weed if there was a sudden decline in CO2 under high light/non limiting nutrients?

    What would happen in the Light reactions?
    There would be a back up of NADPH, ATP and lots and lots of high energy electrons, which can over load the light reactions causign the formation of reactive oxygen radicals.

    These ROS's in turn destroy the very enzymes that are suppose to gather light energy and feed it into the light reactions to send to the dark reactions where the CO2 is fixed.

    By decoupling these light and dark reactions..........this causes a severe back up of incoming light energy => biochemical reactions begin to back up=> these expose the enzymes more and more to ROS's which attack and destroy the enzymes required for photosynthesis.

    http://www.biosensitivefutures.org.a...osynthesis.gif

    See the part that splits the water?
    See the electron carriers and the PQ- and PQ?
    There's a few others, but all these are overloaded with electrons.........they have to go somewhere, so a few start attacking the D1 enzyme that splits the water into O2 and e-.

    Plants can regulate this balance somewhat under optimal conditions, but if the temp goes way up, say 40C, or the CO2 is suddenly gone.........or some other stresses.........then this ROs effect occurs and can be intense.

    Since there is little CO2, there's little food for plants.
    Plants can adapt to some degree, but this takes time and sudden large CO2 changes seems to really cause a lot of issues within submersed plants that are simply not present with terrestrial species.

    We enrich the CO2 so this difference is even larger in many cases. Going up higher in CO2 seems okay, but not dropping or bobbing between high and low.

    I passed BTW(the exam).

    Regards,
    Tom Barr
    www.BarrReport.com

  • #2
    Never A Doubt

    Hi,

    Never a doubt. Congratulation on passing your exam!

    Nice diagram, thank you.

    Without pretending I understood this, I think this is central to understanding the condition we observe when we get CO2 bouncing around or make sudden changes in lighting.

    I suspect it is at least analogous (though different mechanisms) to other large changes we make to the systems (aquariums) that weaken the system and provide nutrients (encouragement) for algal growth.

    Biollante
    The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

    Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.
    • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
    • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
    • When in doubt "don't."

    Comment


    • #3
      Another way to think about, while a bit extreme........it's like removing the lightning rod from the house and having it get struck.

      Instead of sending the electrons where they are suppose to go(the ground), the energy rips through the house destroying things on it's way.

      At the cellular level, this is sort of what happens if there's a sudden back up in the energy.
      Plants have some protection systems, but these are/can be overloaded.

      Regards,
      Tom Barr
      www.BarrReport.com

      Comment


      • #4
        So, you think there's a market for plant sun-block lotion?
        "Do, then talk about it.
        No do? No talk!!" - Tom Barr

        Comment


        • #5
          Is this a problem when bobbing between concentrations of nutrients/CO2 at levels that could be considered non-limiting amounts? For example, bobbing between 30ppm and 40ppm of CO2 would be better then bobbing between 15ppm and 25ppm. Of course, stability would seam to be the best solution overall.

          "I want to take you higher"
          :encouragement: Roll You're Own: Greater Washington Aquatic Plant Association
          Mixed with a sound of water's murmuring
          a sensitive plant in a garden growing.

          Comment


          • #6
            Could it be that these enzymes are evacuated by the plant cells and picked up by algae spores?
            :encouragement: Roll You're Own: Greater Washington Aquatic Plant Association
            Mixed with a sound of water's murmuring
            a sensitive plant in a garden growing.

            Comment


            • #7
              Originally posted by Tug View Post
              Is this a problem when bobbing between concentrations of nutrients/CO2 at levels that could be considered non-limiting amounts? For example, bobbing between 30ppm and 40ppm of CO2 would be better then bobbing between 15ppm and 25ppm. Of course, stability would seam to be the best solution overall.

              "I want to take you higher"
              I doubt there's much issue if there's a non limiting level, non limiting is by it's very definition, non limiting to growth.
              Problems arise when folks assume they have non limiting CO2, when they very well may not.
              Hell, that gets me time to time, even the top scapers in the world will get nails on this one time to time.

              Less observant folks?
              Very likely.
              DIY?
              Same thing, maybe worse.


              Regards,
              Tom Barr
              www.BarrReport.com

              Comment


              • #8
                Originally posted by Tug View Post
                Could it be that these enzymes are evacuated by the plant cells and picked up by algae spores?
                No, proteases chop them up or the cell dies and the enzmyes are already destoyed leak up. Bacteria attack, then perhaps the basic N groups can be used.
                There might be a signalthat leakign stressed plants give off, or perhaps the sudden change itself is a factor in algae.

                But.......as far as plants..........this is what occurs, algae tend to do well at higher light.

                If there's enough growth, algae will roast themselves with O2, 200-300% etc.......toxic O2 levels.

                Regards,
                Tom Barr
                www.BarrReport.com

                Comment


                • #9
                  Periphyton Bloom?

                  Originally posted by Tom Barr View Post
                  Another way to think about, while a bit extreme........it's like removing the lightning rod from the house and having it get struck.

                  Instead of sending the electrons where they are suppose to go(the ground), the energy rips through the house destroying things on it's way.

                  At the cellular level, this is sort of what happens if there's a sudden back up in the energy.
                  Plants have some protection systems, but these are/can be overloaded.

                  Regards,
                  Tom Barr
                  Hi,

                  It would seem that this is an invitation to Periphyton bloom (if that is the right word). The complex little community out of balance would likely favor one group in that community over others, specifically I am thinking of the cyanobacteria component. But really whoever can most efficiently channel the energy and consume the nutrients (waste produced).

                  Biollante
                  The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

                  Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.
                  • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
                  • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
                  • When in doubt "don't."

                  Comment


                  • #10
                    This thread and that chart are going right into my bookmarks. This is another one of those things we should all know at least the basics of, but most don't.

                    It's incredible how many people give up on plants without taking account that the ones they buy from the store are high light/tons of compressed CO2 and they're sending them off into CO2 limiting environments. I've had it happen with my own plants that I've given to others.
                    - Dan

                    Comment


                    • #11
                      They each have their down side. More can go wrong with yeast for less observant folks. On the other hand yeast will give you only so much CO2. A less observant person (someone who works for a living) could very easily gas their fish with pressurized systems.

                      With a yeast reactor most of my focus is on keeping the fermentation from sticking, improving the water flow and adjusting the lighting. Now that I'm close to providing non limiting levels of CO2 I do see some pearling after a water change. I can conjecture that I am close to providing the right amount of CO2, keeping the enzymes from being destroyed completely, but just short of the mark due to flow issues I have yet to address.

                      Originally posted by Tom Barr
                      Less observant folks?
                      Very likely.
                      DIY?
                      Same thing, maybe worse.
                      Last edited by Tug; 05-19-2010, 02:30 PM. Reason: What I ment to say...
                      :encouragement: Roll You're Own: Greater Washington Aquatic Plant Association
                      Mixed with a sound of water's murmuring
                      a sensitive plant in a garden growing.

                      Comment


                      • #12
                        Roasted algae on an open fire, Batman! Toxic O2 levels? Is this some kind of a trick answer?
                        Originally posted by Tom Barr
                        If there's enough growth, algae will roast themselves with O2, 200-300% etc.......toxic O2 levels.
                        :encouragement: Roll You're Own: Greater Washington Aquatic Plant Association
                        Mixed with a sound of water's murmuring
                        a sensitive plant in a garden growing.

                        Comment


                        • #13
                          Vitamin C Anyone?

                          Hi,

                          The reactive oxygen species (ROS) that started this discussion really is no different from folks using hydrogen peroxide to kill cyanobacyeria. For that matter, other attempts to raise ORP values to improve water quality. I do not know if the term “free radicals” apply, but it seems that is what we are fighting.

                          People take vitamin C for the “antioxidant” to fight damage of ROS, deal with those “free radicals.”.

                          I believe, not sure, that when people talk about “cellular signaling” ROS is the method. I think “signaling” is mainly redox or oxidative signaling.

                          It seems odd that when adding sodium percarbonate to the water column, the first thing we see is a significant reduction (scary) in ORP value. To a lesser intellect as me, this seems counter-intuitive.

                          Biollante
                          The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

                          Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.
                          • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
                          • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
                          • When in doubt "don't."

                          Comment


                          • #14
                            Originally posted by Tug View Post
                            Roasted algae on an open fire, Batman! Toxic O2 levels? Is this some kind of a trick answer?
                            Under high growth conditions, algae will over produce O2.
                            Plants are less likely to do this. They tend to be limited by CO2, and floating plant leaves are immune.

                            Regards,
                            Tom Barr
                            www.BarrReport.com

                            Comment


                            • #15
                              Cool!

                              Hi,

                              So this condition of limited CO2 in aquatic plants is rather equivalent to Achim Trebst’s work showing that impeding the electron flow through electron transport chain of photosynthetic apparatus is a source of real problems for green plants generally.

                              That Hoffman, et al in 2005 built on to demonstrate Arabidopsis thaliana, Mouse-ear cress, that heat and water deficiency causing closure of the stomata which in turn triggers lower CO2 in the leaf therefore less photosynthetic production that leads to “indirect” damage caused by the production of free radicals, reactive oxygen species (ROS).

                              Of course, in aquatic plants the CO2 deficiency is not caused by stomata closure but by lack of available dissolved CO2, which is why floating plants are not affected. It also answers one of my questions about signaling.

                              I may not be very smart but this is cool, that was an interesting question, even if it took a while for me to catch on, thanks.

                              Biollante
                              The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

                              Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.
                              • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
                              • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
                              • When in doubt "don't."

                              Comment

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