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The pineapple is an example of a CAM plant.. Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions [1] that allows a plant to photosynthesize during the day, but only exchange gases at night.
Transpiration is the movement of water through a plant and out of its leaves and other aerial parts into the atmosphere. This movement is driven by solar energy. [4] In the tallest trees, such as Sequoia sempervirens, the water rises well over 100 metres from root-tip to canopy leaves. Such trees also exploit evaporation to keep the surface cool.
CAM plants, such as cacti and succulent plants, also use the enzyme PEP carboxylase to capture carbon dioxide, but only at night. Crassulacean acid metabolism allows plants to conduct most of their gas exchange in the cooler night-time air, sequestering carbon in 4-carbon sugars which can be released to the photosynthesizing cells during the day.
At night, transpiration usually does not occur, because most plants have their stomata closed. When there is a high soil moisture level, water will enter plant roots, because the water potential of the roots is lower than in the soil solution. The water will accumulate in the plant, creating a slight root pressure.
Root pressure provides a force, which pushes water up the stem, but it is not enough to account for the movement of water to leaves at the top of the tallest trees. The maximum root pressure measured in some plants can raise water only to 6.87 meters, and the tallest trees are over 100 meters tall.
The oxidation of water is catalyzed in photosystem II by a redox-active structure that contains four manganese ions and a calcium ion; this oxygen-evolving complex binds two water molecules and contains the four oxidizing equivalents that are used to drive the water-oxidizing reaction (Kok's S-state diagrams).
Rolling boil of water in an electric kettle. Boiling or ebullition is the rapid phase transition from liquid to gas or vapour; the reverse of boiling is condensation.Boiling occurs when a liquid is heated to its boiling point, so that the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmosphere.
Calvin–Benson cycle. C 3 carbon fixation is the most common of three metabolic pathways for carbon fixation in photosynthesis, the other two being C 4 and CAM.This process converts carbon dioxide and ribulose bisphosphate (RuBP, a 5-carbon sugar) into two molecules of 3-phosphoglycerate through the following reaction: