In C 3 plants, photorespiration, and the Mehler reaction, are thought to be a principal cause . ( Flexas 2000)
22.
This is energetically costly as the plant has to use energy to turn the products of photorespiration back into a form that can react with.
23.
C4 carbon fixation evolved to circumvent photorespiration, but can occur only in certain plants native to very warm or tropical climates corn, for example.
24.
In the study of plants photorespiration, the labeling of atmosphere by oxygen-18 allows us to measure the oxygen uptake by the photorespiration pathway.
25.
In the study of plants photorespiration, the labeling of atmosphere by oxygen-18 allows us to measure the oxygen uptake by the photorespiration pathway.
26.
This means that often plants may be starved of carbon dioxide as the enzyme that fixes, RuBisCo, also fixes oxygen in the process of photorespiration.
27.
Under these conditions, photorespiration does occur in C 4 plants, but at a much reduced level compared with C 3 plants in the same conditions.
28.
Photorespiration turns RuBP into 3-PGA and 2-phosphoglycolate, a 2-carbon molecule that can be converted via glycolate and glyoxalate to glycine.
29.
Although photorespiration is greatly reduced in C 4 species, it is still an essential pathway-mutants without functioning 2-phosphoglycolate metabolism cannot grow in normal conditions.
30.
This ability to avoid photorespiration makes these plants more hardy than other plants in dry and hot environments, wherein stomata are closed and internal carbon dioxide levels are low.
