Stomatal opening and closingPlants exchange gases through their stomata-CO2 in for Calvin cycle and Rubisco-O2 byproduct of photosynthesis out-Need to open stomata to spongy mesophyll to exchange air in spongy mesophyll-BUT, tradeoff – lose water through stomata as we have seen-How does a plant decide whether to open stomata Role of blue light in opening stomata-blue light wavelengths are one of the peaks of absorbance for chlorophyll-so plants want to do photosynthesis when they sense blue light-stomata are flanked by guard cells guard cells open and close stomata by turgor changing shape of cells (Fig.
For photosynthesis to occur, plants need: · Light energy from the sun · Chlorophyll to absorb light energy · Carbon dioxide from the atmosphere and from respiration in plant cells · Water which is absorbed by the roots and transported to the leaves by the xylem tubes....
In the process of photosynthesis, the plant will chemically convert that gas into sugar, which the plant can use to fuel cellular processes, grow, and reproduce.
The Nucleus Guard cells are specialized cells located in the leaf epidermis of plants Guard cells belong to the Kingdom Plantae What Kingdom Does This Cell Belong To?
38.25)-at the sourcesugars are loaded into sieve tubes at sources (such as in a leaf doing lots of photosynthesis) (phloem loading)so right at that point in the tube, there is high concentration of solute (sugar)so water potential is low compared to surrounding tissue and xylem (because solute potential is high (and by convention solute potentials are always negative, so water potential is low)so water moves from xylem into phloem tubethis increases turgor pressure (pressure potential)lots of water, no where to goso the sugar-rich fluid is pushed through the tubes-at the sinksugars are unloaded into sink cells (phloem unloading)as sugars are unloaded, solute potential of the phloem gets less negative and finally this is less concentrated than fluid in xylemso water potential of fluid is higher than in xylemso water flows into the xylem from the phloem-water potential of phloem at the source is high, at the sink it is low How does phloem loading happen?-Some plants do this entirely through symplast using plasmodesmata (Fig.
When the stomata are shut (guard cells lack water), there is no space for gasses to move in and out of the leaf, limiting the rate of photosynthesis (as CO