Gratitude. Gave her another application of Gibberelin, same as before. What can I do to increase the rate of cellular respiration? We are adding more reactants, like glucose. Photosynthetic efficiency is the fraction of light energy converted into chemical energy during photosynthesis in green plants and algae. The simplified chemical reaction can describe photosynthesis 6 H2O + 6 CO2 + energy → C6H12O6 + 6 O2 where C6H12O6 is glucose (which is subsequently transformed into other sugars, starches, cellulose, lignin, and so forth). The value of the photosynthetic efficiency is dependent on how light energy is defined – it depends on whether we count only the light that is absorbed, and on what kind of light is used (see Photosynthetically active radiation). It takes eight (or perhaps ten or more) photons to use one molecule of CO2. The Gibbs free energy for converting a mole of CO2 to glucose is 114 kcal, whereas eight moles of photons of wavelength 600 nm contains 381 kcal, giving a nominal efficiency of 30%. However, photosynthesis can occur with light up to wavelength 720 nm so long as there is also light at wavelengths below 680 nm to keep Photosystem II operating (see Chlorophyll). Using longer wavelengths means less light energy is needed for the same number of photons and therefore for the same amount of photosynthesis. For actual sunlight, where only 45% of the light is in the photosynthetically active wavelength range, the theoretical maximum efficiency of solar energy conversion is approximately 11%. In actuality, however, plants do not absorb all incoming sunlight (due to reflection, respiration requirements of photosynthesis, and the need for optimal solar radiation levels) and do not convert all harvested energy into biomass, which results in a maximum overall photosynthetic efficiency of 3 to 6% of total solar radiation. If photosynthesis is inefficient, excess light energy must be dissipated to avoid damaging the photosynthetic apparatus. Energy can be dissipated as heat (non-photochemical quenching), or emitted as chlorophyll fluorescence. Starting with the solar spectrum falling on a leaf, 47% lost due to photons outside the 400–700 nm active range (chlorophyll uses photons between 400 and 700 nm, extracting the energy of one 700 nm photon from each one) 30% of the in-band photons are lost due to incomplete absorption or photons hitting components other than chloroplasts 24% of the absorbed photon energy is lost due to degrading short wavelength photons to the 700 nm energy level 68% of the used energy is lost in conversion into d-glucose 35–45% of the glucose is consumed by the leaf in the processes of dark and photorespiration Stated another way: 100% sunlight → non-bioavailable photons waste is 47%, leaving 53% (in the 400–700 nm range) → 30% of photons are lost due to incomplete absorption, leaving 37% (absorbed photon energy) → 24% is lost due to wavelength-mismatch degradation to 700 nm energy, leaving 28.2% (sunlight energy collected by chlorophyll) → 68% is lost in conversion of ATP and NADPH to d-glucose, leaving 9% (collected as sugar) → 35–40% of sugar is recycled/consumed by the leaf in dark and photo-respiration, leaving 5.4% net leaf efficiency. Far-red In efforts to increase photosynthetic efficiency, researchers have proposed extending the spectrum of light that is available for photosynthesis. One approach involves incorporating pigments like chlorophyll d and f, which are capable of absorbing far-red light, into the photosynthetic machinery of higher plants. Naturally present in certain cyanobacteria, these chlorophylls enable photosynthesis with far-red light that standard chlorophylls a and b cannot utilize. By adapting these pigments for use in higher plants, it is hoped that plants can be engineered to utilize a wider range of the light spectrum, potentially leading to increased growth rates and biomass production. Green Green light is considered the least efficient wavelength in the visible spectrum for photosynthesis and presents an opportunity for increased utilization. Chlorophyll c is a pigment found in marine algae with blue-green absorption and could be used to expand absorption in the green wavelengths in plants. Expression of the dinoflagellate CHLOROPHYLL C SYNTHASE gene in the plant Nicotiana benthamiana resulted in the heterologous production of chlorophyll c. This was the first successful introduction of a foreign chlorophyll molecule into a higher plant and is the first step towards bioengineering plants for improved photosynthetic performance across a variety of lighting conditions. Photosynthesis by day, Cellular respiration by night. Co2 doesn't change the parameters of the environment that are suitable for the plant. Co2 increases the efficiency with which the plant captures carbon from the air and mixes with water using stored energy from photosyynthesis into carbo(sugar)hydrates(water). Max energy a plant can convert in any one cycle is 40 mole per day at 400 ppm. 60 mole per day at 12-1800 ppm. Notice that light intensity, carbon dioxide concentration, and temperature are the three main factors that impact photosynthesis. Greater light intensity leads to higher photosynthesis rates, as does increased carbon dioxide concentration. Temperature is also directly linked to the rate of respiration Q10 Temperature coefficient. This is a key factor affecting photosynthesis. Low CO2 affects the Calvin Cycle. If CO2 levels are low, rubisco cannot convert RuBP to GP in step one of the Calvin Cycle. This leads to the accumulation of RuBP and an overall slowing of the Calvin Cycle, which results in a fall in the production of TP/GALP. CO2 is not needed at night so turn it off. Nights should be focused on respiration and dealing with excess moisture spat into the air all night long, keeping ambient canopy RH 40-45%. This keeps a constant negative pressure overnight. Oxygen is what a plant needs at night, only oxygen diffuses into the leaves and only carbon dioxide diffuses out. Vpd is just a measure of temperature and humidity. The drier the air the more space it has to spit more moisture out. As soon as those lights go out she is just spitting moisture. All the energy the plant collects during the day must be processed overnight. Grow tents at night reaching upward of 65%RH or thereabouts things start to drift from optimal. If the plant only converts a percent of all the energy it gathered during the day and doesn't process it all that night, the plant keeps a surplus which will detract from the next day's DLI. I was surprised, stunned even at how much more water she needed to maintain the intense daytime cooling. Daytime priority is keeping temps under 86 and hitting a DLI of 40-60moles, supplement CO2. Nighttime is about maxing out the rate of respiration and getting rid of water ASAP. To make use of all the energy stored in the stems the plant needs to convert a lot of the stored energy to sugars then the plant mixes them with nutrients to make more complex cells, more nutrients, and more water until there is no energy left stored in those stems. If we don't optimize night cycle, like everything else with cannabis plants, the entire production of the plant as a whole will bottleneck at the place in the line that is least efficient. At night If you can stick to 40-45%RH, you should keep semi-optimal turgor pressure, negative pressure, and humidity for quick removal of water vapor generated under the stomata. Keeping 40-45 % should mean keeping temps around 73-83 and keeping your VPD in the "green" for most of the flowering period. I kinda think of it like PH, in that 6.5 is not the best for every nutrient but it's about balance across the spectrum of variables. VPD is similar. Becomes very hard to micro-manage if you focus on too many controllers its hard to keep everything perfect always. You can't keep it perfect 100%, all the time, well you can but the electrical cost of doing so very quickly changes your mind as electrical components sensors start fighting each other and cycling 24/7. I made the decision to pack everything the plant will ever need and then some into the soil, letting the plant dictate its own feeding schedule based on the demand the environment places on it.