Photorespiration

[SheffJoe]

Photorespiration

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Post by SheffJoe » Wed May 16, 2012 11:14 am

When plants are in hot environments they'll close stomata to prevent water loss. This closing of stomata leads to low levels of CO2 which leads to photorespiration. But where is the oxygen coming from for photorespiration? In my textbook it says that it is coming from photolysis during the light-dependent stage of photosynthesis. However, surely if the stomata are closed, transpiration stops and so the level of water in the plant decreases????

[JackBean]

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Post by JackBean » Wed May 16, 2012 11:24 am

First, to my knowledge, oxygen is produced during photosynthesis. Second, water is mainly transported from roots and evaporated through stomata. Thus closing stomata does not reduce intake of water.

[EmperorSunshine]

Re:

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Post by EmperorSunshine » Wed May 23, 2012 4:23 am

Second, water is mainly transported from roots and evaporated through stomata. Thus closing stomata does not reduce intake of water.

Pedantry: I thought the evaporation of water through the stomata creates suction which is one of the several mechanisms that draw water upwards into the leaves (the other mechanisms being capillary action and osmotic pressure). So closing the stomata DOES reduce the intake of water.

[JackBean]

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Post by JackBean » Wed May 23, 2012 1:17 pm

So, if the amount of water decreases, does it function in other way so it does not take the water from roots?