Linear Relationships between Photosynthetic Rate and Photochemical Energy Expressed by PAR ×Fv/Fm ()
ABSTRACT
Photosynthetic rate (Pn) of plants is simultaneously affected by
photosynthetically active radiation (PAR)
and maximum yield of primary photochemistry (Fv/Fm).
In order to explore the quantitative relationship between Pn, PAR and Fv/Fm, those parameters were simultaneously measured for
different plant species (maize, sunflower, daylily and alfalfa), growth stages
and irrigation treatments. Results indicated that the diurnal variation of Pn had no significant
correlation with that of Fv/Fm. Mean diurnal values of Pn were linearly correlated
with those of Fv/Fm among the different
irrigation treatments of alfalfa (p <
0.05), but this linear correlation was not observed among the different
species. There was a positive relationship between Pn and Fv/Fm only at midday (12:00 and
14:00) (p < 0.01). A significant
linear relationship was observed between the diurnal variation of Pn and PAR × Fv/Fm (p < 0.05), this law was suitable for the different species, and
the different growth stages and the different irrigation treatments of the same
species. This study confirms that Pn is significantly related to the photochemical energy (PAR × Fv/Fm), the light energy
directly used in photochemical reactions of plants.
Share and Cite:
Sun, D. and Wang, Q. (2018) Linear Relationships between Photosynthetic Rate and Photochemical Energy Expressed by
PAR ×
Fv/Fm.
American Journal of Plant Sciences,
9, 125-138. doi:
10.4236/ajps.2018.92011.