POWERING PHOTOSYNTHESIS
Seedlings and young plants require a lower light intensity than more
mature crops.
Most plants respond well to CO2 levels in the 3001,500 ppm range. Below 200 ppm, CO2 begins to limit
plant growth, but if levels creep above 2,000 ppm, CO2
becomes toxic to many plants and 5,000 ppm is the
threshold for human safety. There is much debate over
the level of enrichment that will give the highest rate
of photosynthesis under different growing conditions.
Plants will use more CO2 under warm, high-light
conditions than under duller, cooler conditions, and
enrichment levels can be adjusted to account for this.
Most plants respond
well to CO2 levels in the
300-1,500 ppm range.”
Light and Humidity
So now we know that light levels,
light quality and CO2 levels affect
the rate of photosynthesis and a
number of other plant processes.
The effects of humidity are a little
more indirect. Low humidity (high
vapor-pressure deficit) can cause large
volumes of water carried in the transpiration stream to be
lost from the leaf surface to the air and force the plant to
shut down its stomata to prevent desiccation.
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Maximum Yield USA | December 2015