Effect of plastic film mulching on photosynthetic and fluorescence characteristics of corn leaf under different fertilization schemes at jointing stage

Plastic film mulching (PFM) and different fertilization schemes were conducted in corn fields in the black soil region of Northeast China at jointing stage and the effect on the physiological characteristics of photosynthesis and chlorophyll analyzed. The results reveal the following: PFM significantly increases photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and water use efficiency (WUE). It has no effect on intercellular CO₂ concentration (Ci) and stomatal limitation (Ls). PFM has a stronger effect on photosynthetic parameters of corn treated with only nitrogen or phosphorus than those treated with other fertilizer types. PFM significantly increases Fm value, Fv/Fm and Fv/Fo ratios of corn treated with P and PK fertilizer. However, PFM significantly decreases Fmvalue, and Fv/Fm and Fv/Fo ratios of corn treated with NPK fertilizers.