Linear Relationships between Photosynthetic Rate and Photochemical Energy Expressed by PAR ×Fv/Fm

摘要

Photosynthetic rate ( style="font-family:Verdana;">P _{style="font-family:Verdana;">n} style="font-family:Verdana;">) of plants is simultaneously affected by photosynthetically active radiation ( style="font-family:Verdana;">PAR style="font-family:Verdana;">) and maximum yield of primary photochemistry ( style="font-family:Verdana;">F _{style="font-family:Verdana;">v} style="font-family:Verdana;">/ style="font-family:Verdana;">F _{style="font-family:Verdana;">m} style="font-family:Verdana;">). In order to explore the quantitative relationship between style="font-family:Verdana;">P _{style="font-family:Verdana;">n} style="font-family:Verdana;">, style="font-family:Verdana;">PAR style="font-family:Verdana;"> and style="font-family:Verdana;">F _{style="font-family:Verdana;">v} style="font-family:Verdana;">/ style="font-family:Verdana;">F _{style="font-family:Verdana;">m} style="font-family:Verdana;">, 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 style="font-family:Verdana;">P _{style="font-family:Verdana;">n} style="font-family:Verdana;"> had no significant correlation with that of style="font-family:Verdana;">F _{style="font-family:Verdana;">v} style="font-family:Verdana;">/ style="font-family:Verdana;">F _{style="font-family:Verdana;">m} style="font-family:Verdana;">. Mean diurnal values of style="font-family:Verdana;">P _{style="font-family:Verdana;">n} style="font-family:Verdana;"> were linearly correlated with those of style="font-family:Verdana;">F _{style="font-family:Verdana;">v} style="font-family:Verdana;">/ style="font-family:Verdana;">F _{style="font-family:Verdana;">m} style="font-family:Verdana;"> among the different irrigation treatments of alfalfa ( style="font-family:Verdana;">p style="font-family:Verdana;"> < 0.05), but this linear correlation was not observed among the different species. There was a positive relationship between style="font-family:Verdana;">P _{style="font-family:Verdana;">n} style="font-family:Verdana;"> and style="font-family:Verdana;">F _{style="font-family:Verdana;">v} style="font-family:Verdana;">/ style="font-family:Verdana;">F _{style="font-family:Verdana;">m} style="font-family:Verdana;"> only at midday (12:00 and 14:00) ( style="font-family:Verdana;">p style="font-family:Verdana;"> < 0.01). A significant linear relationship was observed between the diurnal variation of style="font-family:Verdana;">P _{style="font-family:Verdana;">n} style="font-family:Verdana;"> and style="font-family:Verdana;">PAR style="font-family:Verdana;"> × style="font-family:Verdana;">F _{style="font-family:Verdana;">v} style="font-family:Verdana;">/ style="font-family:Verdana;">F _{style="font-family:Verdana;">m} style="font-family:Verdana;"> ( style="font-family:Verdana;