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#1
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| I came across the following quote, > and many plants are Is this true? Can anyone site a source for this information? I know most plants consume CO2 in the day and O2 at night, but the above statement seems counter intuitive. TIA -- You can lead a horse to water, but you can't hold his head under 'til the bubbles stop. - |
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#2
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| In article <caj1i.81$[Only registered users see links. ]>, Buddy <why.wood.yew@bother> wrote: I suspect this is somebody's folk etymology for the term "nightshade". Actually, they consume O2 all the time, but with light, they can photosynthesize, consuming CO2 and producing sugars and oxygen. As to actual growth, i.e. producing more and larger cells, they do that all the time, as long as they have enough light, water, heat, nutrients, etc, except when dormant, of course. |
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#3
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| [Only registered users see links. ] so bravely stated: Thanks for the reply. Remembering a bit from high school, aren't we talking about ATP/ADP - photosynthesis vs. respiration? Or are photosynthesis and respiration concurrent and not separated by night and day. TIA -- You can lead a horse to water, but you can't hold his head under 'til the bubbles stop. - |
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#4
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| > Remembering a bit from high school, aren't we talking about ATP/ADP - photosynthesis and respiration can simultaneously occur - there are certain plants that have specific adaptations (usually due to heat, dessication, light, etc.) that either spatially (C4) or temporally (CAM plants, which I think is causing the confusion here) separate the influx of CO2 and the process of converting it to sugar. remember that all living things respire, and so the sugars that plants produce through photosynthesis that don't go to their structure (cellulose, lignin, etc.) or shared with symbiotes (mycorrhizal fungi, etc.) are burned for energy. total generalizations: photosynthesis takes water and CO2; using the energy from light converts them to sugar and O2 (waste). (aerobic) respiration takes sugar and O2; within the organism they get converted to ATP and CO2 (waste). |
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#5
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| It depends how you define plant growth. If you define growth as an increase in plant dry weight, then the answer is probably no because a gain in dry weight occurs mainly in the light for photosynthetic plants, except possibly CAM plants. However, if you define growth as an increase in size, then many plants may also grow at night because growth requires water pressure (turgor) to expand cells. During the day, plants often have lower turgor because of their rapid transpiration rate (Munns et al. 2000). Munns et al. (2000) also note that internal hormonal controls can override plant water status effects on leaf elongation depending on the time scale. Huber and Hanson (1992) found that leaf expansion occurred mainly at night for a wild-type tobacco. However, a starchless mutant tobacco expanded its leaves mainly during the day. David R. Hershey References Plant Growth Challenge [Only registered users see links. ] Huber, S.C. and Hanson, K.R. 1992. Carbon Partitioning and Growth of a Starchless Mutant of Nicotiana sylvestris. Plant Physiology 99(4): 1449-1454. [Only registered users see links. ] Munns, R. et al. 2000. Water relations and leaf expansion: Importance of time scale. Journal of Experimental Botany 51: 1495-1504. [Only registered users see links. ] Buddy wrote: |
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#6
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| carrie norin so bravely stated: Thanks for taking the time to answer my question, Carrie. -- You can lead a horse to water, but you can't hold his head under 'til the bubbles stop. - |
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#7
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| grow , night , plants |
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