In
botany, a light curve shows the
photosynthetic
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in c ...
response of leaf tissue or algal communities to varying light intensities. The shape of the curve illustrates the principle of
limiting factors; in low light levels, the rate of photosynthesis is limited by the concentration of
chlorophyll
Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to a ...
and the efficiency of the
light-dependent reactions, but in higher light levels it is limited by the efficiency of
RuBisCo and the availability of
carbon dioxide. The point on the curve where these two differing slopes meet is called the light saturation point and is where the light-dependent reactions are producing more
ATP
ATP may refer to:
Companies and organizations
* Association of Tennis Professionals, men's professional tennis governing body
* American Technical Publishers, employee-owned publishing company
* ', a Danish pension
* Armenia Tree Project, non ...
and
NADPH
Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require NAD ...
than can be utilized by the
light-independent reactions. Since photosynthesis is also limited by ambient carbon dioxide levels, light curves are often repeated at several different constant carbon dioxide concentrations.
References
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Photosynthesis